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1
Cassinath, Zen. "Development of twin screw Rheo extrusion technology." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7608.
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Twin Screw Rheo Extrusion (TSRE) is a novel semisolid extrusion process developed at BCAST for producing simple profiles such as rods and wires of light alloys directly from melts with refined microstructures and improved mechanical properties. The process represents a shortened manufacturing route with great savings in investment, energy consumption and operation space. Research was carried out to investigate the feasibility of processing magnesium and aluminium alloys, to obtain the operations for the optimized microstructures and mechanical properties of the final product and to understand the mechanisms governing the evolution of microstructures. Experiments were conducted using an AZ91D magnesium alloy and several aluminium alloys on two specially made twin screw rheo extrusion machines and a range of conditions were tested. Results showed that the TSRE process was feasible for the AZ91D magnesium alloy and aluminium alloys, although modifications were required for processing aluminium alloys as the twin screw material used was found to react with aluminium. Analysis revealed that the extruded samples of both alloys had a uniform fine microstructure in both transversel and longitudinal directions and liquid segregation was limited, due to the application of intensive shearing during slurry making and extrusion. Low extrusion temperature was found to refine the structure and suppress the formation of the eutectic. The eutectic was easily dissolved upon heat treatment resulting in reasonable mechanical properties. Numerical analysis on thermal management was carried out and the results showed that a steady state thermal profile with a temperature gradient between the slurry feeding point and extrusion die could be established, promoting nucleation and preventing the formed solid particles from extensive growth during extrusion, which was confirmed by microstructural observations.
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Edi-Soetaredjo, Felycia. "Numerical simulation of twin-screw extrusion of starch based material /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18502.pdf.
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Winstone, Gemma. "Production of catalyst supports by twin screw extrusion of pastes." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/5706/.
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The production of ceramic catalyst supports is commonly performed by the extrusion of a paste. The rheological properties of the paste as it passes through the extruder have a strong influence on the extrudate properties such as porosity and strength, which in turn affect the catalytic performance of the final product. An assessment of the effect of acid type and strength and powder type on the rheological properties of concentrated boehmite slurries has been made. In particular, evidence of gel formation is looked for, and the surface chemistry is examined using zeta potential measurements. Further understanding of the observed rheological changes is obtained by performing nuclear magnetic resonance studies and cryogenic microscopy. The effect of powder properties and acid type and strength on the saturation states of a formulation has been examined using mixer torque rheometry. The prediction of saturation states from bulk density measurements is discussed. The predictive capability of the mixer torque rheometer with regards extrusion formulations is investigated. The effect of acid type and strength on successful extrusion formulations and extrudate properties is discussed.
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Lewis, Todd M. "Carbon Nanotube Composites Prepared by Ultrasonically Assisted Twin Screw Extrusion." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405330978.
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Xu, Suxuan. "Fibrous soy protein meat analog from low moisture twin-screw extrusion." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6035.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 16, 2008) Includes bibliographical references.
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Rongzhi, Huang. "MULTILAYER CO-EXTRUSION AND TWIN-SCREW COMPOUNDING OF POLYMERIC ELASTOMER SYSTEMS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1404864078.
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Stasiek, Andrzej. "Badania procesu współbieżnego dwuślimakowego wytłaczania modyfikowanego polipropylenu przy zmiennej geometrii ślimaków." Rozprawa doktorska, Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy, 2015. http://dlibra.utp.edu.pl/Content/886.
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Celem pracy było badanie i opis wybranych cech konstrukcyjnych ślimaków wytłaczarki dwuślimakowej współbieżnej oraz parametrów technologicznych procesu na właściwości kompozytów PP/talk wytworzonych w tym procesie
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Strandberg, Marcus. "Determination and implementation of polymer parameters into simulations of the twin-screw extrusion process." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-27184.
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This thesis was conducted in cooperation with a Swedish company that develops and manufactures plastic compounds. An increasing need for identifying material properties is seen within the industry in order to predict the outcome of the extrusion process by using simulations. The purpose of this study was to expand a material database with the results obtained through various measurements of the material parameters in order to enable simulations. The numerical descriptions would be analyzed and validated in relation to the obtained results and conducted methods to enable implementation of the material data into the industry. In order to fulfill the purpose, scientific methods was applied by chosen literature studies, research approaches and experimental research. Machine tests were conducted to collect relevant output data that was compared with the results obtained during the simulation process where the experimentally determined material parameters were applied in a material database. Typical injection molding qualities of PET, POM, PC/ABS, SAN and PA66 has been investigated by conducting measurement methods described by standards of the melt flow rate, specific heats, viscosity, crystallinity and melt- and glass transition temperatures. With exception of the viscosity, the material parameters are considered to have high external validity and high reliability and can be implemented into the industry. The bulk- and melt density was determined by adapted methods that need further investigations. The external validity is reduced until these methods and measurements have been validated. The determined material parameters proved to be able to generate reliable simulation results that indicate of how the extrusion process will turn out based on the output values investigated. The data obtained through machine tests was compared with the results that were achieved through simulations and deviated at most 10.9% from the actual outcomes. The viscosity is considered to be the main factor that affects the differences of the output data between the machine tests and the simulation results.
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Ng, Thian Hong. "Twin screw extrusion pre-treatment of wheat straw for biofuel and lignin biorefinery applications." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7417.
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Pre-treatment of wheat straw(lignocellulosic) biomass is a crucial step as it has direct impact on the subsequent yield of enzymatic saccharification and alcohol fermentation processes in the production of biofuel. Twin screw extrusion is a highly feasible pretreatment method and has been received great interest in the recent year pre-treatment studies. Twin screw extrusion is a continuous process, where the biomass feedstock can be subjected to a combination of simultaneous physical, thermal and chemical treatments. Steam explosion is a batch process and is the most commonly used method for lignocellulosic pre-treatment. In the initial stage of this study, the yield of glucose obtained from enzymatic saccharification for both methods (extrusion and steam explosion) were compared to identify the most effective pre-treatment approach. Effectiveness of the conventional steam explosion pre-treatment was used as benchmark for the directions of development of effective extrusion fractionation for wheat straw. In subsequent study, the impact of physical operating parameters (moisture, barrel temperature, compaction, screw speed and size reduction before extrusion) over twin screw extrusion with and without NaOH were studied. Low temperature (50°C) and increased moisture extrusion were preferred extrusion conditions. Yield of glucose can be improved by addition of NaOH (0.04g / g straw) and barrel temperature profile optimisation. Post extrusion washing was recommended. Findings from FTIR and TGA help to understand the chemical and structural changes took place in the pre-treatment and can be correlated with the glucose yield at the end of enzymatic hydrolysis. Characterisation analysis was extended to FT-NIR, morphology, crystallinity and specific surface area analysis to analyse the structural changes of lignocellulose biomass in extrusion pre-treatment and correlation with glucose yield. Chemometric analysis was used to statistically process large amounts of spectral data. The PCA scores plots showed good cluster segregation of the samples and were thus able to distinguish the effects of different pre-treatment conditions. The PLS regression models for both FTIR and FT-NIR showed good statistical regression and predictive ability correlated to the glucose yield. For the lignin ultilisation study, crude lignin was recovered from black liquor and fractionated with solvents. Lignin and the fractions were characterised with solvent solubility, SEC, UV, FTIR, 1H and 13C NMR and evaluated for the antioxidant activity with AAI ranged from 0.3 to 2.4. Reason for the low performance was proposed and experiment was extended to the intended application performance screening. Lignin application study was further extended to assess the feasibility of using lignin as an antioxidant in carboxylated acrilonitrile-butadiene rubber, XNBR glove. Evaluation involved physical observation, mechanical properties and thermal analysis – DSC-OIT after incorporation of lignin into XNBR glove. Lignin antioxidant performance was compared with current chemical antioxidant in used in industry. A part from antioxidant behaviour, lignin was also found can enhance the softness of XNBR film after accelerated heat aging.
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Likhar, Lokesh. "The production of a lyotropic liquid crystal coated powder precursor through twin screw extrusion." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6352.
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The twin screw extrusion technique has been explored to produce lyotropic liquid crystal coated powder precursor by exploiting Pluronic F127 thermoreversible gelation property to get powder precursor without granular aggregates or with less compacted granular aggregates. The highly soluble chlorpheniramine maleate loaded in Pluronic F127 solution coated MCC particles prepared through twin screw extrusion was examined to produce the cubic phase (gel) for the development of controlled release formulation and for coating of very fine particles which cannot be achieved by traditional bead coaters. Controlled release formulations are beneficial in reducing the frequency of administration of highly soluble drugs having short half life and also to address the problem of polypharmacy in old age patients by reduction of dosage frequency. An unusual refrigerated temperature (5 C) profile for twin screw extrusion was selected based on the complex viscoelastic flow behaviour of Pluronic F127 solution which was found to be highly temperature sensitive. The Pluronic F127 solution was found to be Newtonian in flow and less viscoelastic at low temperature, such that low temperature (5¿C) conditions were found to be suitable for mixing and coating the MCC particles to avoid compacted aggregates. At higher temperatures (35-40¿C) Pluronic F127 solution exhibited shear thinning and prominent viscoelasticity, properties which were exploited to force CPM containing Pluronic F127 solution to stick over the MCC surface. This was achieved by elevating the temperature of the last zone of the extrusion barrel. It was found that to avoid compacted aggregates the MCC must be five times the weight of the Pluronic F127 solution and processed at a screw speed of 400 RPM or above at refrigerated temperature. Processing was not found to be smooth at ambient temperature with frictional heat and high torque generation due to significant compaction of coated particles which can be attributed to the elastic behaviour of Pluronic F127 solution at temperatures between ambient to typical body temperature. PLM images confirmed the cubic phase formation (gel) by Pluronic F127 coating which was found to be thick with maximum Pluronic F127 concentration (25%). SEM images showed smoothing of surface topography, and stretching and elongation of MCC fibres after extrusion which is indicative of coating through extrusion processing. Plastic deformation was observed for the lower Pluronic F127 concentration and higher MCC proportions. There was a significant decrease in work done for cohesion by the powder flow analyser observed in the batches with more aggregates compared with batches with least aggregates. A regression analysis study on factorial design batches was conducted to investigate the significant independent variables and their impact on dependent variables for example % torque, geometric mean diameter and work done for cohesion, and to quantitatively evaluate them. From the regression analysis data it was found that the coefficient of determination for all three dependent variables was in the range of 55-62%. The pharmaceutical performance of the prepared coated LLC precursor through twin screw extrusion in terms of controlled release was found to be very disappointing. Almost 100% chlorpheniramine maleate was released within 10-15mins, defined as providing burst release. The MDSC method was developed within this work to detect Pluronic F127 solution cubic phase formation. The MDSC method was developed to consider sample size, effect of heating and cooling, sample heat capacity, and the parameters for highest sensitivity which can be followed by sample accurately without the phase lag to produce accurate repeatable results.
11
Elsey, Justin Rae. "Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders." University of Sydney. Department of Chemical Engineering, 2003. http://hdl.handle.net/2123/687.
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Co-rotating twin-screw extruders are unique and versatile machines that are used widely in the plastics and food processing industries. Due to the large number of operating variables and design parameters available for manipulation and the complex interactions between them, it cannot be claimed that these extruders are currently being optimally utilised. The most significant improvement to the field of twin-screw extrusion would be through the provision of a generally applicable dynamic process model that is both computationally inexpensive and accurate. This would enable product design, process optimisation and process controller design to be performed cheaply and more thoroughly on a computer than can currently be achieved through experimental trials. This thesis is divided into three parts: dynamic modelling, measurement and control. The first part outlines the development of a dynamic model of the extrusion process which satisfies the above mentioned criteria. The dynamic model predicts quasi-3D spatial profiles of the degree of fill, pressure, temperature, specific mechanical energy input and concentrations of inert and reacting species in the extruder. The individual material transport models which constitute the dynamic model are examined closely for their accuracy and computational efficiency by comparing candidate models amongst themselves and against full 3D finite volume flow models. Several new modelling approaches are proposed in the course of this investigation. The dynamic model achieves a high degree of simplicity and flexibility by assuming a slight compressibility in the process material, allowing the pressure to be calculated directly from the degree of over-fill in each model element using an equation of state. Comparison of the model predictions with dynamic temperature, pressure and residence time distribution data from an extrusion cooking process indicates a good predictive capability. The model can perform dynamic step-change calculations for typical screw configurations in approximately 30 seconds on a 600 MHz Pentium 3 personal computer. The second part of this thesis relates to the measurement of product quality attributes of extruded materials. A digital image processing technique for measuring the bubble size distribution in extruded foams from cross sectional images is presented. It is recognised that this is an important product quality attribute, though difficult to measure accurately with existing techniques. The present technique is demonstrated on several different products. A simulation study of the formation mechanism of polymer foams is also performed. The measurement of product quality attributes such as bulk density and hardness in a manner suitable for automatic control is also addressed. This is achieved through the development of an acoustic sensor for inferring product attributes using the sounds emanating from the product as it leaves the extruder. This method is found to have good prediction ability on unseen data. The third and final part of this thesis relates to the automatic control of product quality attributes using multivariable model predictive controllers based on both direct and indirect control strategies. In the given case study, indirect control strategies, which seek to regulate the product quality attributes through the control of secondary process indicators such as temperature and pressure, are found to cause greater deviations in product quality than taking no corrective control action at all. Conversely, direct control strategies are shown to give tight control over the product quality attributes, provided that appropriate product quality sensors or inferential estimation techniques are available.
12
Elsey, Justin Rae. "Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders." Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/687.
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Co-rotating twin-screw extruders are unique and versatile machines that are used widely in the plastics and food processing industries. Due to the large number of operating variables and design parameters available for manipulation and the complex interactions between them, it cannot be claimed that these extruders are currently being optimally utilised. The most significant improvement to the field of twin-screw extrusion would be through the provision of a generally applicable dynamic process model that is both computationally inexpensive and accurate. This would enable product design, process optimisation and process controller design to be performed cheaply and more thoroughly on a computer than can currently be achieved through experimental trials. This thesis is divided into three parts: dynamic modelling, measurement and control. The first part outlines the development of a dynamic model of the extrusion process which satisfies the above mentioned criteria. The dynamic model predicts quasi-3D spatial profiles of the degree of fill, pressure, temperature, specific mechanical energy input and concentrations of inert and reacting species in the extruder. The individual material transport models which constitute the dynamic model are examined closely for their accuracy and computational efficiency by comparing candidate models amongst themselves and against full 3D finite volume flow models. Several new modelling approaches are proposed in the course of this investigation. The dynamic model achieves a high degree of simplicity and flexibility by assuming a slight compressibility in the process material, allowing the pressure to be calculated directly from the degree of over-fill in each model element using an equation of state. Comparison of the model predictions with dynamic temperature, pressure and residence time distribution data from an extrusion cooking process indicates a good predictive capability. The model can perform dynamic step-change calculations for typical screw configurations in approximately 30 seconds on a 600 MHz Pentium 3 personal computer. The second part of this thesis relates to the measurement of product quality attributes of extruded materials. A digital image processing technique for measuring the bubble size distribution in extruded foams from cross sectional images is presented. It is recognised that this is an important product quality attribute, though difficult to measure accurately with existing techniques. The present technique is demonstrated on several different products. A simulation study of the formation mechanism of polymer foams is also performed. The measurement of product quality attributes such as bulk density and hardness in a manner suitable for automatic control is also addressed. This is achieved through the development of an acoustic sensor for inferring product attributes using the sounds emanating from the product as it leaves the extruder. This method is found to have good prediction ability on unseen data. The third and final part of this thesis relates to the automatic control of product quality attributes using multivariable model predictive controllers based on both direct and indirect control strategies. In the given case study, indirect control strategies, which seek to regulate the product quality attributes through the control of secondary process indicators such as temperature and pressure, are found to cause greater deviations in product quality than taking no corrective control action at all. Conversely, direct control strategies are shown to give tight control over the product quality attributes, provided that appropriate product quality sensors or inferential estimation techniques are available.
13
Singh, D. P. "Flow and mixing studies in a co-rotating intermeshing twin screw extruder." Thesis, Brunel University, 1988. http://bura.brunel.ac.uk/handle/2438/5548.
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The basic understanding of mixing in the process of polymer melt extrusion by twin screw extruder is limited by their geometrical complexity and the interactions of the process parameters. Mixing and flow in a 100mm diameter, trapezoidal channeled, intermeshing co-rotating twin-screw extruder have been characterised by determination of residence time distribution (RTD) and of the paths taken by tracers added to the melt. The axial mixing and the effects of varius parameters on it were established by studying RTD using tracer techniques. As the tail of the distribution is of paramount importance, the reproducibility of the RTD curve was extensively studied. Radioactive NnO2 was used as a tracer and detected by gamma ray spectroscopy giving more reproducible results than added barytes estimated gravimetrically after ashing. Shock cooling of the extruder and sectioning of the solidified compound in the screw channels was used to-study the flow mechanism. The maximum throughput achieved, polymer melting mechanism, filled volume and axial mixing Are interrelated, and are dependent on the configuration and position of segmented mixing discs present in the screw profile. In the upstream position these act as melting discs and their efficiency is increased in a closed configuration. Initial melting is achieved over a remarkably short distance along the screw profile. The screw speed affects the axial mixing which is shown to be related to the net relative pressure change at the screw tips. A flow model is proposed such that the overall material flow taking place in an anticlockwise direction along the screw channel comprises two separate flow regimes. The upper regime rotates anti-clockwise and is made up of main and small tetrahedron flow and calender flow. The lower flow regime rotates clockwise and is made up of main and small side leakage flows and a portion of the main tetrahedron flows together with a central flow. The flow studies show conclusively that the melt from a particular site ahead of the intermeshing zone occupies a predestined site after passing through the intermeshing zone.
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Colas, Dorothée. "Etude de la bioraffinerie des plantes vertes : Application au fractionnement des protéines de luzerne par extrusion bi-vis et chromatographie hydrophobe." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0019/document.
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La luzerne est une plante fourragère, de la famille des Fabacées, largement cultivée en France du fait de sa richesse en protéines. Industriellement, cette plante est pressée, puis séchée sur tambour rotatif. L’étape de pressage conduit à l’obtention de grandes quantités de jus, lui aussi riche en protéines. L’objectif de cette thèse a été de développer un procédé de bioraffinerie de la luzerne, applicable aux autres plantes fourragères, permettant la valorisation des toutes les fractions de la plante. La première étape consiste en un fractionnement thermo-mécanique de la luzerne entière par extrusion bi-vis. Deux fractions sont obtenues : un résidu fibreux solide en partie déshydraté, pouvant être utilisé dans la filière agro-matériaux, et un filtrat vert, riche en protéines. L’extrusion bi-vis est une alternative intéressante aux procédés classiques de déshydratation, car l’étude de l’optimisation des paramètres d’extrusion a permis de montrer qu’il est possible de récupérer la grande majorité des protéines de la plante dans le filtrat. Ce filtrat subit par la suite une séparation liquide/solide par centrifugation, permettant la récupération d’un culot vert, dont on peut extraire la chlorophylle. Le jus clarifié est ultrafiltré, puis traité par chromatographie hydrophobe, avec l’huile de tournesol comme solvant extracteur, de manière à séparer différentes protéines. L’étude plus fondamentale de la fixation des protéines sur résine a permis de modéliser le fractionnement des protéines par interactions hydrophobesAlfalfa is a common Legume, cultivated as a forage crop, thanks to its high protein content. In the green crop industry, alfalfa is pressed and dried on a rotative cylinder. The pressing step leads to the production of large amounts of green juice, rich in proteins. The aim of this work was to develop a biorefinery process for alfalfa, which could be adapted to other green crops, allowing the valorization of each fraction. The first step is the whole plant thermo-mechanical fractionation in the twin-screw extruder. Two fractions are obtained: a solid fibrous residue, partly dehydrated which could be valorized as an agro-material, and a green filtrate, rich in proteins. Twin-screw extrusion is an interesting alternative to usual industrial dehydration processes. Indeed, the study of the extruder parameters optimization showed that most of the alfalfa proteins can be recovered in the filtrate. This green extract is then centrifuged, in order to separate the solid particles. Chlorophyll can be extracted from the centrifugation pellet. The clarified juice is treated by ultrafiltration, and lastly fractionated thanks to hydrophobic chromatography, with sunflower oil as the solvent, in order to separate the proteins. The more fundamental study of proteins fixation on resins allowed us to modelize proteins fractionation using hydrophobic interactions
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Gallant, Frederick Mitchell. "Continuously graded extruded polymer composites for energetic applications fabricated using twin-screw extrusion processing technology." College Park, Md. : University of Maryland, 2003. http://hdl.handle.net/1903/92.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2003.Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Castro, Gutierrez Natalia. "Incorporation and release of organic volatile compounds in a bio-based matrix by twin-screw extrusion." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/16006/1/Castro_Natalia.pdf.
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Nowadays, scientific and political communities are focused on ways to better preserve and manage the natural resources of our planet. In order to reduce consumption of fossil resources, and to develop more environmentally friendly industrial processes, the industry of flavors and fragrances became interested in developing new bio-based encapsulating materials. In the present work, maltodextrins have been chosen as main component of the matrix, and pea protein isolate and a modified starch were selected as compatibilizing additives. The incorporation of volatile odorant compounds and the elaboration of the new bio-based delivery systems were performed, all in one single step, by low temperature twin-screw extrusion. The physicochemical, thermal and morphological properties of these matrices were studied, as well as the encapsulation efficiency and the release profile of the active compounds. These investigations have led to a better understanding of the impact of the formulations and of the incorporation of the active compound on the process parameters. The interactions between the wall and the encapsulated materials were also analyzed. The characteristics of the new bio-based delivery systems and the established extrusion process conditions were found to be very promising to be employed in the field of perfumery.
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Rol, Fleur. "Prétraitements de la cellulose pour une nanofibrillation par extrusion." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI009.
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Ce projet vise à développer un nouveau procédé de fabrication de nanofibrilles de cellulose (NFC) à fort taux de matière sèche et en consommant peu d’énergie. L’extrusion bi-vis, technique industrielle, efficace énergétiquement et facilement adaptable fut ainsi utilisée pour produire des NFC à 20%. En diminuant considérablement la teneur en eau, cette nouvelle stratégie permet de diminuer le coût du transport, d’améliorer le stockage et d’élargir leur domaine d’application. Ce travail a consisté (i) à développer de nouveaux prétraitements chimiques des fibres de celluloses, respectueux de l’environnement pour faciliter la fibrillation de la cellulose et produire des NFC fonctionnelles de qualité, (ii) à optimiser les conditions d’extrusion ainsi que le profil de vis et (iii) à préparer des matériaux à partir de cette nouvelle matière. Quatre prétraitements chimiques ont été identifiés comme facilement industrialisables et ensuite optimisés. La nanofibrillation par extrusion a été ensuite simulée par un logiciel pour obtenir des conditions d’extrusion optimisées. La production de NFC de qualité à l’échelle semi-industrielle a été validée. Différentes applications ont été envisagées pour ces nouvelles NFC à fort taux de matière sècheThis project aims at developing a new process to produce high solid content cellulose nanofibrils (CNF) decreasing the energy consumption and preserving the high quality compared to classic processes. Twin screw extrusion (TSE), industrially well-known, energy efficient and highly adaptable technique, was optimized to produce CNF at 20 wt% solid content. By decreasing considerably the water content, this new strategy improves the transport cost, the storage and widening the field of application and formulation. The objectives were to (i) develop new green pretreatments of cellulose fibers to facilitate the fibrillation and produce high quality functionalized CNF, (ii) optimize TSE screw profile and conditions to produce CNF and (iii) prepare new materials made of this new type of CNF. Four chemical pretreatments of cellulose fibers have been identified as industrially feasible, leading to high quality functionalized CNF and were widely studied and optimized. The nanofibrillation by TSE was simulated using a simulation software and TSE conditions were then successfully optimized. This cost-effective approach was validated at semi-industrial scale. Finally, different new applications with this new grade of CNF were considered
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Fong, Lopez Monica. "Développement d'un procédé de dégradation enzymatique de la biomasse lignocellulosique mettant en œuvre des moyens thermo-mécano-chimiques." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0060.
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Le bioéthanol lignocellulosique est potentiellement une source durable de remplacement des combustibles fossiles. Cependant, pour atteindre une phase de commercialisation de cette technologie, des barrières techniques doivent être franchies au niveau de chaque étape de production : prétraitement, saccharification, fermentation et distillation. Un procédé de déconstruction de la biomasse comportant les étapes de prétraitement alcalin, neutralisation, filtration et imprégnation enzymatique dans un extrudeur bi-vis a été développé lors du projet BABETHANOL (2010-2013). L’optimisation de ce procédé est entreprise dans cette étude en utilisant comme matière végétale modèle, le coproduit de maïs doux (CMD). La première partie de cette étude traite sur la diminution du coût relié à l’emploi de produits chimiques lors des étapes de prétraitement alcalin et de neutralisation. Pour cela, plusieurs stratégies ont été étudiées : la modification de l’agent alcalin employé lors de l’étape de prétraitement (NaOH, KOH et Ca(OH)2) et la modification de la température et la concentration en alcalin lors des étapes de prétraitement. Les résultats obtenus montrent la possibilité de diminuer la charge en alcalin avec une augmentation de la température de prétraitement. L’optimisation du prétraitement alcalin a ainsi permis une diminution de la charge en soude et acide employés, ce qui s’est traduit par une diminution de 5 millions d’euros des coûts opératoires annuels du procédé. La deuxième partie de cette étude aborde l’optimisation des étapes d’imprégnation enzymatique en extrudeur bi-vis et d’hydrolyse enzymatique consécutives en réacteur. Premièrement, l’étude s’est focalisée sur l’étude de l’impact de la modification du ratio liquide/solide et de la charge enzymatique appliquées lors de cette étape de bioextrusion. Par la suite, l’implémentation des étapes consécutives de prétraitement – imprégnation enzymatique-saccharification/fermentation consécutives est traitée. De ce fait, une série d’essais ont été menés en couplant l’extrudeur bivis à un réacteur de 22L où la saccharification ou/et la fermentation ont été poursuivies. Au bilan, ces travaux présentent un procédé en continue adaptable à grande échelle, et avec un rendement à échelle laboratoire de 12,7 Kg d’éthanol pour 100Kg de coproduit de maïs doux secLignocellulosic bioethanol is a sustainable alternative to replace fossil fuels. However, technical barriers at each operational step (pretreatment, saccharification, fermentation and distillation) are part of the bottlenecks for its commercialization. A process counting with an alkaline pretreatment, neutralization, filtration and enzymatic impregnation within a twin screw extruder was set up during BABETHANOL project (2010-2013). The optimization of the process was undertaken in the present study with Sweet Corn Coproduct (SCC) as model raw biomass. In the first part of the study, the conditions of the alkaline pretreatment were evaluated in order to diminish the chemical load, thus reducing their economic cost. For this matter, different strategies were employed: the modification of the chemical agent (NaOH, KOH and Ca(OH)2), the temperature and alkali load of the pretreatment. The results indicate that sodium hydroxide exhibits a higher efficiency and a lower cost than potassium hydroxide and calcium hydroxide. An increase of temperature can balance the reduction of chemical input, thus diminishing annual operating costs of the process by 5 million euros. In the second part of the study, the research focuses on the optimal conditions of enzymatic impregnation, also called bioextrusion. Firstly the study the impact of the liquid/solid ratio and the enzymatic load apply during bioextrusion on saccharification at high consistency was carried out. Furthermore, the evaluation of the conditions of the implementation of the consecutive pretreatment- bioextrusion-saccharification/fermentation was performed. For this matter, a series of essays were executed with the whole process set up at lab-scale, i.e. extruder coupled with a 22L reactor. At the outcome, the research work presents a continuous process with the possibility of scale-up that presents a yield of 12.7Kg of ethanol with 100Kg of dry sweet corn coproduct
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Liang, Tian. "Continuous Devulcanization of Ground Tire Rubber of Different Particle Sizes Using an Ultrasonic Twin-Screw Extruder." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366063285.
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Zhong, Jing. "Ultrasonically aided extrusion in preparation of polymer composites with carbon fillers." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460413630.
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Gamon, Guillaume. "Incorporation de fibres végétales dans des matrices thermoplastiques biosourcées et biodégradables par extrusion bi-vis pour la production de matériaux biocomposites moulés par injection." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0029.
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L’incorporation de fibres végétales, différentes par leur origine, leur nature chimique et leur forme, a été effectuée dans deux matrices thermoplastiques : le poly(acide lactique) et la farine de blé thermoplastifiée. Ces deux matrices biodégradables et biosourcées ont elles aussi des natures chimiques et des propriétés thermo-mécaniques différentes. Des incorporations de fibres jusqu’à 40 % en poids ont permis de modifier considérablement les propriétés de base des matrices et d’améliorer certaines de leurs faiblesses (stabilité thermique, manque de rigidité…). Les fibres de miscanthus ont été sélectionnées comme étant les plus performantes pour l’amélioration des propriétés des deux matrices. Les propriétés des matériaux composites ont été ajustées par un travail sur la formulation du mélange (ajout de plastifiants) et l’optimisation du procédé complet, jusqu’au moulage par injection. L’incorporation des fibres dans un mélange compatibilisé des deux matrices a également été testée et réalisée en une seule étape d’extrusion, comprenant la plastification de la farine, le mélange des polymères et la dispersion des fibresIncorporation of vegetal fibres, differing by their source, their chemical composition and their shape, have been performed by twin screw extrusion in two thermoplastic matrices: the poly(lactic acid) and the thermoplastified wheat flour. These two biobased and biodegradable matrices have also different chemical character and thermo-mechanical properties. Fibre incorporation up to 40 % in weight considerably modified both matrix properties and improved several weaknesses (thermal stability, lack of stiffness…). Miscanthus fibres have been selected as best improvers for properties of both matrices. Materials properties were adjusted with a formulating work (addition of plasticizers) and whole process optimization, until injection-molding. Fibre incorporation in a compatibilized blend of the two matrices was also tested and performed in a one step extrusion process, including flour thermoplasticization, polymer blending and fibre dispersion
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Mogni, Assad. "Fractionnement des complexes lignine-polysaccharides issus de différentes biomasses lignocellulosiques par extrusion bi-vis et séparation chromatographique." Thesis, Toulouse, INPT, 2015. http://www.theses.fr/2015INPT0099/document.
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L’objectif de ces travaux est de développer une nouvelle voie de valorisation de différents coproduits agricoles et forestiers. L’étude s’est focalisée sur l’étape de séparation entre les hémicelluloses et les lignines contenues dans des extraits aqueux obtenus par extrusion bi-vis. La technologie bi-vis du fait de sa modularité a été choisie pour évaluer différentes conditions d’extraction. Les essais ont été menés afin de mettre en évidence l’influence des effets mécanique, thermique et chimique sur l’extraction des hémicelluloses à partir des différentes matrices végétales étudiées. Les travaux ont été conduits soit en conditions hydrothermales, eau sous pression et haute température, soit en conditions faiblement alcalines pour extraire des molécules les plus natives possibles. Ceci a permis d’identifier les conditions d’extraction les plus favorables en fonction des caractéristiques de chacune des biomasses. Dans un second temps, les extraits obtenus, contenants des hémicelluloses et des composés phénoliques, ont été purifiés au moyen de méthode de fixation sur résines d’échange d’ions et d’adsorption. Les travaux se sont focalisés sur la compréhension des mécanismes de fixation des molécules avec des solutions modèles contenant un ou plusieurs solutés. La cinétique et les isothermes d’échanges ont été évaluées pour l’acide férulique, l’acide coumarique et la lignine. Les résultats ont ensuite été comparés à ceux obtenus avec les extraits alcalins. Cette étude a permis d’identifier les mécanismes d’échanges qui interviennent lors de la séparation des complexes lignine-polysaccharidesThe objective of this work is to validate a new way of valuing various agricultural and forestry coproducts. Study was devoted on the separation of lignin and hemicelluloses contained in extracts obtained by twin-screw extrusion. Twin-screw technology has been chosen to evaluate different extraction conditions. Trial conditions have been adopted in order to highlight the influence of mechanical, thermal and chemical effects on the extraction performances for various plant matrices. Efforts have been made to give priority to mild extraction conditions in the interest of preserving the integrity of the extracted polymers and limiting the environmental impact. Thus hydro-thermal extraction tests without chemical solvents were compared to more conventional alkaline extraction to evaluate their efficiency. This identified the most favorable extraction conditions according to the characteristics of each biomass. The extracts, with hemicelluloses and phenolic compounds, were purified with ion exchange and adsorption resins. Work focused on mechanisms fixations characterization with model solutions conditions containing one or several molecules. Kinetic and isotherm were determined for lignin, coumaric acid and ferulic acid. Then, results were compared to results obtained with the extracts. This study allowed to identify the mechanisms involved in the separation of the lignin-carbohydrates complex
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Agrawal, Akash. "Examining the Effectiveness of Different Mixing Elements in the Twin Screw Compounding of Liquid Crystal Polymer and Polypropylene." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1512742062745962.
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Gatt, Etienne. "Etude de la déconstruction de résidus agricoles lignocellulosiques par extrusion biocatalytique." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0006/document.
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L’extrusion biocatalytique, ou bioextrusion, est une technique d’extrusion réactive utilisant des enzymes comme catalyseurs. Cette technique est considérée en temps qu’étape intermédiaire, subséquente au prétraitement physico-chimique et précédente à l’hydrolyse enzymatique enréacteur fermé. L’utilisation de l’extrusion permet un procédé continu, facilement modulable et adaptable à des conditions de hautes consistances, de nombreuses biomasses et facilement transférable à l’échelle industrielle. Néanmoins, les données bibliographiques font ressortir la complexité des entrants et leurs interactions lors de la bioextrusion de biomasses lignocellulosiques. Les conclusions des bioextrusions de biomasses amidonnées soulignent l’importance de l’étude de l’influence de la concentration en substrat et en enzymes. Les résultats obtenus à partir de la bioextrusion des biomasses lignocellulosiques valident l’existence d’une activité enzymatique en extrudeuse malgré la contrainte thermomécanique et le temps de séjour limité. Lors de cette étape, l’hydrolyse de la fraction cellulosique est favorisée pour des milieux concentrés en substrat et en enzymes. Des modifications significatives des fractions cellulosiques cristallines et amorphes en surface, des réductions des tailles de particules, une dégradation visuelle des structures de la biomasse et l’augmentation de la sensibilité à la décomposition thermique, sont aussi observées sur la fraction solide. L’hydrolyse enzymatique des bioextrudats est prolongée en réacteur fermé. La bioextrusion permet des améliorations significatives des taux et vitesses de conversion des sucres sur le long terme, jusqu’à 48 h. Les gains observés sont relativement constants pour la paille de blé et augmentent avec le temps pour les écorces de bouleau et les résidus de maïs. Post-extrusion, la concentration en substrat influence négativement la conversion des sucres. Cependant, les plus-values de conversion du glucose lié à la bioextrusion de paille de blé sont principalement observables pour des concentrations en substrat et en enzymes élevées. À partir de 4 h, des baisses significatives de la conversion du xylose sont observées après bioextrusion. Les déstructurations de la fraction solide, déjà observées au cours la bioextrusion, se poursuivent en réacteur fermé. Les meilleurs résultats hydrolytiques aux niveaux des hautes charges en enzymes et en substrat sont associables aux bonnes conditions de mélanges caractéristiques des éléments bilobes. L’ensemble enzymatique est probablement réparti de façon plus homogène (mélange distributif) pour cibler plus de sites disponibles. De plus, le mélangé dispersif limite la proximité entre enzymes de même type et les gênes associées. Le procédé d’extrusion permet une agitation efficace, un bon transfert de masse et probablement un meilleur contact entre enzymes et substrat. Les moins bons résultats de conversion du xylose sont probablement à relier à des phénomènes d’adsorption non-spécifique, ou encore de désactivation des hémicellulases, provoqués par l’intensité des contraintes thermomécaniques et les résidus ligneux. Les bons résultats de déstructuration après bioextrusionsont associables à une action synergétique des contraintes mécanique et biochimique. Les analyses d’autofluorescence montrent l’évolution de la fraction ligneuse dans le processus de déconstruction de la fraction solide. Une production progressive de particules très fines,visiblement associée à la fraction ligneuse, est observée. Des complexes lignine-carbohydratessont aussi détectés dans la fraction liquide. Etant peu, voire pas hydrolysable par voie enzymatique, ces fractions hétéropolymériques sont un frein à la déconstruction. Si la déstructuration des lignines est probablement majoritairement liée au prétraitement alcalin, le procédé de bioextrusion provoque une diminution de la teneur en hétéropolymères de plus hautes masses moléculairesBiocatalytic extrusion, also named bioextrusion, is a reactive extrusion technique using enzymes as catalysts. Bioextrusion is considered as a link between the previous physico-chemical pretreatment (like alkaline extrusion) and the subsequent enzymatic hydrolysis in batch conditions. The extrusion allows a continuous, flexible and versatile process for high consistency media, easily transferable to the industrial level. However, complexity of both lignocellulosic biomass and lignocellulolytic enzymes and their interactions during the extrusion process are underlined by the literature. Numerous response surface methodology experiments with starchy biomass indicate that bioextrusion efficiency is mainly influenced by substrate and enzymes loading. Enzymatic activity during the bioextrusion process of lignocellulosic biomass is confirmed by the experiments despite the mechanical constraints and the limited residence time. During bioextrusion, best holocellulosic fraction hydrolysis results were obtained with high substrate and enzymes loadings. Significant modifications of the solid fraction like particule size reduction, visual deconstruction of the biomass structure, increased sensibility to thermal decomposition and the evolution of the surface exposure of crystalline and amorphous cellulose were observed. Enzymatic hydrolysis of the bioextrdates is prolonged in batch conditions. Clear improvements of speeds and rates of sugars conversion up to 48 h indicate a long term influence of the bioextrusion. Gain observed are steady for the pretreated wheat straw whereas it increases with time for corn residues and birch barks. Post-extrusion, a negative influence of the substrate loading is measured. However, best enhancements for the glucose conversion of pretreated wheat straw are detected for high substrate and enzymes loadings. From 4 to 48 h, significant losses in xylose conversion are measured with previous bioextrusion. Indicators of the solid fraction deconstruction, observed during the bioextrusion step, indicate a stronger biomass degradation after 48 h. Improvements of glucose conversion rates can be associated with good mixing conditions of the extruder, especially due to the use of kneading elements. Enzymes are probably more homogeneously distributed (distributive mixing) and can access more catalytic sites available. Moreover, dispersive mixing limits the enzyme jamming due to the biocatalysts concentration. Extrusion process permits an better agitation efficiency, good mass transfer conditions and probably a higher contact between substrate and enzymes. Lower xylose conversion results may be attributed to non-specific adsorptions or inactivation phenomena due to mechanical constraints and lignin residues. Good deconstruction results on the solid fraction may be associable with a synergetic action between mechanical and biochemical constraints. Autofluorescent signal analysis of the lignin fraction show its evolution during the deconstruction of the solid residue. During the hydrolysis, a progressive production of very small particles, appearing to be associated with the lignin fraction is observed. Lignin-carbohydrate complexes are also detected in the liquid fraction. These heteropolymeric complexes, difficult or even impossible for the enzymes to hydrolyze, are an obstacle to the biomass valorization. If lignin deconstruction is mainly due to the alkaline pretreatment, bioextrusion process seems to reduce the proportion of these heteropylymers with high molecular weights
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Brault, Julien. "Développement d'un procédé innovant de dégradation enzymatique des parois végétales pour la production de bioéthanol seconde génération." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0088.
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Les procédés de transformation de biomasse lignocellulosique en bioéthanol de seconde génération sont actuellement des sujets de recherche très répandus mais ne sont toujours pas compétitifs avec ceux de la première génération. Les facteurs clés limitants sont : l’efficacité et les coûts du prétraitement, les rendements de l’hydrolyse enzymatique, et la co-fermentation C5-C6. Un procédé continu de déconstruction de la matière végétale, compactant un prétraitement thermo-mécano-chimique utilisant un agent alcalin avec une introduction d’enzymes en extrusion bi-vis, appelé bioextrusion, est développé dans cette étude. Il permet de préparer la matière cellulosique à un haut taux de matière sèche (>20%), à une saccharification et une fermentation pouvant être simultanées (SSF). Le traitement continu peut extraire une grande part des hémicelluloses (jusqu’à 97%) et des lignines (>50%) et améliorer l’accessibilité de la cellulose tout en initiant sa dépolymérisation par des cocktails enzymatiques pendant la bioextrusion. Plusieurs matières premières (Résidu de maïs doux, Bagasse d’agave bleue, Résidu d’huilerie de palme, Paille d’orge, Résidu d’Eucalyptus, Sarments de vigne et Bagasse de canne à sucre) ont été caractérisées et leurs comportements vis-à-vis du procédé ont été comparés. L’évolution de la composition de ces matières à travers le procédé et leur hydrolysabilité ont été étudiées. Suite au traitement, une augmentation du rendement de saccharification dans un réacteur (24h de temps de réaction à 20% de consistance) a été obtenue pour ces matières (jusqu’à 85% des C6 théoriques et 70% des C5-C6 théoriques). Les rendements de fermentation non optimisés atteignent un maximum de 85% théorique des sucres C6 convertis, 65% théorique des C5-C6 convertis, et une concentration d’éthanol de 15g/100g extrudat sec. Le procédé de production d’éthanol dans son ensemble (avec addition de l’énergie de la valorisation des coproduits) atteint un ratio « énergie consommée/produite » de 0.5-0.6. Le nouveau procédé présente ainsi les avantages de minimiser la consommation d’énergie par l’application de faibles températures, de minimiser la consommation d’eau par l’utilisation de faibles ratios liquide/solide, de ne pas produire d’inhibiteurs de fermentation et d’être rapide, compact, continu et adaptable sur différentes biomassesLignocellulosic biomass transformation processes in order to produce second generation bioethanol are actually widely studied all around the world but still not yet competitive compare to the first generation. The limiting key factors of the different processes are: the pre-treatment efficiency and costs, the enzymatic hydrolysis yields, and the co-fermentation C5-C6. A continuous plant matter deconstruction process, compacting a thermo-mechanico-chemical pre-treatment using alkali solution with an enzymes injection in twin-screw extruder, called bioextrusion, is developed in this study. It allows preparing the cellulosic material at a high dry matter content (>20%), to a possible simultaneous saccharification and fermentation (SSF). This continuous treatment may extract a big part of hemicelluloses (until 97%) and lignin (>50%) and configures cellulose to a better accessibility and a start of its depolymerisation by enzymes cocktail during the bioextrusion. Several raw matters (Sweet Corn Cob and Spathe, Blue Agave Bagass, Oil Palm Empty Fruit Bunch, Barley Straw, Eucalyptus Residue, Grape Pruning Residue and Sugarcane Bagass) have been characterized and theirs behaviours toward to the process were compared. Evolutions of these matters compositions throughout the process and their hydrolysability have been studied. Further to the treatment, an improvement of the saccharification yields in reactor (24h reaction time at 20% consistency) has been obtained on these matters (until 85% of theoretical C6 and 70% of theoretical C5-C6). The not optimized fermentation yields reach a maximum of 85% of theoretical converted C6 sugars, 65% of theoretical converted C5-C6 sugars, and an ethanol concentration of 15g/100g dry matter extrudate. The whole ethanol production process (with addition of energy from the recovery of the by-products) is achieved with a “consumed/produced energy” ratio of 0.5-0.6. The new process presents the advantages to minimize the energy consumption by operating low temperatures, to minimize water consumption by working at low liquid/solid ratio, to not produce fermentation ‘s inhibitors and to be quick, compact, continuous and adaptable to different biomasses
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Bryson, Latoya G. "Monomer recovery from nylon carpets via reactive extrusion." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22618.
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Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2008.Committee Chair: Muzzy, John D.; Committee Member: Cook, Fred L.; Committee Member: Jones, Christopher W.; Committee Member: Mayor, J. Rhett; Committee Member: Realff, Matthew J.; Committee Member: Schork, F. Joseph.
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Wood, Clive John. "Investigation of a solvent-free continuous process to produce pharmaceutical co-crystals : understanding and developing solvent-free continuous cocrystallisation (SFCC) through study of co-crystal formation under the application of heat, model shear and twin screw extrusion, including development of a near infrared spectroscopy partial least squares quantification method." Thesis, University of Bradford, 2016. http://hdl.handle.net/10454/14580.
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This project utilised a novel solvent-free continuous cocrystallisation (SFCC) method to manufacture pharmaceutical co-crystals. The objectives were to optimize the process towards achieving high co-crystal yields and to understand the behaviour of co-crystals under different conditions. Particular attention was paid to the development of near infrared (NIR) spectroscopy as a process analytical technology (PAT). Twin screw, hot melt extrusion was the base technique of the SFCC process. Changing parameters such as temperature, screw speed and screw geometry was important for improving the co-crystal yield. The level of mixing and shear was directly influenced by the screw geometry, whilst the screw speed was an important parameter for controlling the residence time of the material during hot melt extrusion. Ibuprofen – nicotinamide 1:1 cocrystals and carbamazepine – nicotinamide 1:1 co-crystals were successfully manufactured using the SFCC method. Characterisation techniques were important for this project, and NIR spectroscopy proved to be a convenient, accurate analytical technique for identifying the formation of co-crystals along the extruder barrel. Separate thermal and model shear deformation studies were also carried out to determine the effect of temperature and shear on co-crystal formation for several different pharmaceutical co-crystal pairs. Finally, NIR spectroscopy was used to create two partial least squares regression models, for predicting the 1:1 co-crystal yield of ibuprofen – nicotinamide and carbamazepine – nicotinamide, when in a powder mixture with the respective pure API. It is believed that the prediction models created in this project can be used to facilitate future in-line PAT studies of pharmaceutical co-crystals during different manufacturing processes.
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Walker, Alasdair Michael. "Extrusion processing of chocolate crumb paste." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:1c54a2e6-a767-4fd3-8bf0-e2d250b7ac4a.
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This project considers the co-rotating twin screw extrusion of a confectionery paste comprising powdered proteins, sugars, water and fats. As is the case with many food industry products, this process has been developed experimentally with little quantitative understanding of how variations in processing conditions influence the formation of the extrudate. A variety of techniques have therefore been developed to characterise and quantify the dispersive mixing, distributive mixing and rheological flow properties of this complex, multiphase, viscoelastic, unstable material. These techniques have then been utilised in a pilot plant extruder study of the mechanics of mixing and paste formation during extrusion, considering the influence of both processing conditions and screw profile. The internal evolution of paste microstructure has been successfully tracked along the length of screw profile using dead-stop extractions of the screws. A rigorous off-line assessment of shear yield strength behaviour using cone penetrometry has shown the use of conventional off-line rheometers to be unviable due to rapid post extrusion hardening. This highlighted the need for an in-line rheological measurement technique for continuous extrusion analysis where the extruded material is severely time dependent and not extractable. In pursuit of this, a novel arrangement of bender elements is proposed and trialled, to rapidly characterise material parameters of viscoelastic pastes. A second technique looking to extend the application of shear wave interface reflection to multiphase pastes is also trialled. A novel analysis of thermogravimetric data (TGA) has generated a viable index of distributive mixing, suitable for use on complex multi-component materials where thermal decomposition temperatures of the components are not well defined. Quantitative image analysis of pastes using scanning electron microscopy (SEM), optical microscopy protein staining and a novel application of multiphoton microscopy (MPM) have been used to visualise paste microstructure and quantify dispersive mixing. From the pilot plant extruder study, the application of these techniques was successful in mapping the evolution of paste mixing and the resulting microstructure, as well as identifying key differences between pastes mixed by twin screw extrusion and batch mixing.
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Fu, Tingrui. "PP/clay nanocomposites : compounding and thin-wall injection moulding." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24655.
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This research investigates formulation, compounding and thin-wall injection moulding of Polypropylene/clay nanocomposites (PPCNs) prepared using conventional melt-state processes. An independent study on single screw extrusion dynamics using Design of Experiments (DoE) was performed first. Then the optimum formulation of PPCNs and compounding conditions were determined using this strategy. The outcomes from the DoE study were then applied to produce PPCN compounds for the subsequent study of thin-wall injection moulding, for which a novel four-cavity injection moulding system was designed using CAD software and a new moulding tool was constructed based upon this design. Subsequently, the effects of moulding conditions, nanoclay concentration and wall thickness on the injection moulded PPCN parts were investigated. Moreover, simulation of the injection moulding process was carried out to compare the predicted performance with that obtained in practice by measurement of real-time data using an in-cavity pressure sensor. For the selected materials, the optimum formulation is 4 wt% organoclay (DK4), 4 wt% compatibiliser (Polybond 3200, PPgMA) and 1.5 wt% co-intercalant (erucamide), as the maximum interlayer spacing of clay can be achieved in the selected experimental range. Furthermore, DoE investigations determined that a screw speed of 159 rpm and a feed rate of 5.4 kg/h are the optimum compounding conditions for the twin screw extruder used to obtain the highest tensile modulus and yield strength from the PPCN compounds. The optimised formulation of PPCNs and compounding conditions were adopted to manufacture PPCN materials for the study of thin-wall injection moulding. In the selected processing window, tensile modulus and yield strength increase significantly with decreasing injection speed, due to shear-induced orientation effects, exemplified by a significantly increased frozen layer thickness observed by optical microscopy (OM) and Moldflow® simulation. Furthermore, the TEM images indicate a strong orientation of clay particles in the flow direction, so the PPCN test pieces cut parallel to the flow direction have 36.4% higher tensile modulus and 13.6 % higher yield strength than those cut perpendicular to the flow direction, demonstrating the effects of shear induced orientation on the tensile properties of thin-wall injection moulded PPCN parts. In comparison to injection speed, mould temperature has very limited effects in the selected range investigated (25-55 °C), in this study. The changes in moulding conditions show no distinctive effects on PP crystallinity and intercalation behaviour of clay. Impact toughness of thin wall injection moulded PPCN parts is not significantly affected by either the changes in moulding conditions or clay concentration (1-5 %). The SEM images show no clear difference between the fracture surfaces of PPCN samples with different clay concentrations. TEM and XRD results suggest that higher intercalation but lower exfoliation is achieved in PPCN parts with higher clay content. The composites in the thin sections (at the end of flow) have 34 % higher tensile modulus and 11 % higher yield strength than in the thicker sections, although the thin sections show reduced d001 values. This is attributed to the significantly enhanced shear-induced particle/molecular orientation and more highly oriented frozen layer, according to TEM, OM and process simulation results. In terms of the reduced d001 values in the thin sections, it is proposed that the extreme shear conditions in the thin sections stretch the PP chains in the clay galleries to a much higher level, compaction of clay stacks occurs as less interspacing is needed to accommodate the stretched chains, but rapid cooling allows no time for the chains to relax and expand the galleries back. Overall, data obtained from both actual moulding and simulation indicate that injection speed is of utmost importance to the thin-wall injection moulding process, development of microstructure, and thus the resulting properties of the moulded PPCN parts, in the selected experimental ranges of this research.
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Fouilloux, Alessandro. "Formulations du glycérol pour l'amélioration et l'élargissement des propriétés de fonction du film de caséinate de sodium." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSES021.
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Dans un contexte de développement durable, le caséinate de sodium (forme neutralisée de la protéine du lait, la caséine) fait l'objet d'une transformation en un matériau thermoplastique par des procédés de plasturgie tels que l'extrusion. Les études menées depuis plus de vingt ans ont montré que le glycérol est un plastifiant incontournable pour cette matrice biodégradable et comestible.Dans ce manuscrit, des formulations du glycérol ont été menées avec succès. D'une part, l'addition de triéthanolamine et/ou d'hexamétaphosphate de sodium avec le glycérol permettent de modifier les propriétés du film (mécaniques, sorption en eau). D'autre part, la formulation du glycérol sous forme d'émulsions corps gras/glycérol permet de transporter des composés hydrophobes dans la matrice caséinate de sodium. Les corps gras sont ici l'huile de noisettes, stable thermiquement, et l'acide oléique. Grâce à une émulsion huile de noisettes/glycérol, il est possible de véhiculer un principe actif lipophile: l'huile essentielle d'amande amère, connue pour ses propriétés antimicrobiennes. De plus, une vectorisation de l'extrait de romarin, aux propriétés antioxydantes, est aussi rendue possible grâce à des microcapsules 100% naturelles.Ce manuscrit présente le potentiel et la capacité du film de caséinate de sodium à s'orienter vers le domaine du "smart packaging", lui permettant d'être utilisé dans de nombreux domaines tels que l'agroalimentaire ou la détergenceIn a context of sustainable development, sodium caseinate (neutralized form of milk protein, casein) is transformed into a thermoplastic material by plastic processing such as extrusion. Studies conducted for more than 20 years have shown that glycerol is an unavoidable plasticizer for this biodegradable and edible matrix.In this manuscript, formulations of glycerol have been successfully carried out. Firstly, addition of triethanolamine and/or sodium hexametaphosphate with glycerol allows a modification of the film properties (mechanical or water sensitive properties). On the other hand, formulation of glycerol as a lipid/ glycerol emulsion allows a transport of hydrophobic compounds in the sodium caseinate matrix. Studied lipids are hazelnut oil, thermally stable, and oleic acid. Thanks to a hazelnut oil/glycerol emulsion, it is possible to transport an active lipophilic ingredient: essential oil of bitter almond, known for its antimicrobian properties. Moreover, a vectorization of rosemary extract with antioxidant properties is possible with 100% natural microcapsules.This manuscript shows the ability fo sodium caseinate films to be oriented into "smart packaging", that can be used in many sectors such as food industry or detergency
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Chabrat, Elodie. "Développement de nouvelles formulations d'agromatériaux thermoplastiques par mélange en extrudeur bivis de céréales et de polymères issus de ressources renouvelables." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0036/document.
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Dans ce travail de thèse, nous nous sommes intéressés au mélange de la farine de blé et du poly(acide lactique). La farine de blé, qui est composée principalement d'amidon, a été thermoplastifiée en extrudeur bivis par l'effet conjugué de la chaleur et du cisaillement en présence de plastifiants. Le poly(acide lactique) est, quant à lui, le polyester biodégradable le plus répandu à l'heure actuelle. Le mélange de ces deux phases est thermodynamiquement immiscible et peu compatible, différents leviers sont testés afin d'améliorer la qualité du mélange. Une première partie de ce travail repose sur la recherche de conditions optimales pour la transformation et le mélange des matières premières. L'extrusion bivis est utilisée à la fois pour plastifier l'amidon et pour assurer un bon mélange entre les phases. Le profil de vis et les différents équipements sont donc choisis en conséquence. Différents paramètres classiques de l'extrusion bivis sont étudiés : le profil de vis, le profil de température, le taux de remplissage… L'étude de la formulation, notamment des plastifiants utilisés pour la plastification de l'amidon mais également l'utilisation de compatibilisants pour améliorer l'interface amidon/PLA est traitée en deuxième partie. L'acide citrique est testé à la fois comme plastifiant et comme compatibilisant. Ces investigations nous ont permis de mettre au point différents grades intéressants répondant à des applications industrielles distinctes : injectabilité, souplesse, rigidité…In this work, we have been interested in blending wheat flour and poly(lactic acid). Wheat flour, which is mainly constituted of starch, has been transformed with plasticizers in a twin-screw extruder with the effect of heat and shear. Poly(lactic acid) is the main biodegradable polyester in the world nowadays. These two phases are thermodynamically immiscible and not very compatible, different ways are tried to improve the blend quality. A first part of this work lies on the search of optimal conditions to transform and blend the raw materials. Twin-screw extrusion is used to pasticize starch and to ensure a good blending between the two phases. Screw design and different equipments have been chosen for this purpose. Classical twin-screw parameters have been studied: screw design, temperature profile, filling ratio… The study of the formulation, more particularly of plasticizers for starch plasticization but also of compatibilizers to improve starch/PLA interphase is tackled in a second part. Citric acid is tested as a plasticizer but also as a compatibilizer. These researches have allowed to develop interesting formulations for industrial applications: possibility of processing by injection-molding, flexibility, rigidity…
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Chabrat, Elodie. "Développement de nouvelles formulations d'agromatériaux thermoplastiques par mélange en extrudeur bivis de céréales et de polymères issus de ressources renouvelables." Electronic Thesis or Diss., Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0036.
Full textAbstract:
Dans ce travail de thèse, nous nous sommes intéressés au mélange de la farine de blé et du poly(acide lactique). La farine de blé, qui est composée principalement d'amidon, a été thermoplastifiée en extrudeur bivis par l'effet conjugué de la chaleur et du cisaillement en présence de plastifiants. Le poly(acide lactique) est, quant à lui, le polyester biodégradable le plus répandu à l'heure actuelle. Le mélange de ces deux phases est thermodynamiquement immiscible et peu compatible, différents leviers sont testés afin d'améliorer la qualité du mélange. Une première partie de ce travail repose sur la recherche de conditions optimales pour la transformation et le mélange des matières premières. L'extrusion bivis est utilisée à la fois pour plastifier l'amidon et pour assurer un bon mélange entre les phases. Le profil de vis et les différents équipements sont donc choisis en conséquence. Différents paramètres classiques de l'extrusion bivis sont étudiés : le profil de vis, le profil de température, le taux de remplissage… L'étude de la formulation, notamment des plastifiants utilisés pour la plastification de l'amidon mais également l'utilisation de compatibilisants pour améliorer l'interface amidon/PLA est traitée en deuxième partie. L'acide citrique est testé à la fois comme plastifiant et comme compatibilisant. Ces investigations nous ont permis de mettre au point différents grades intéressants répondant à des applications industrielles distinctes : injectabilité, souplesse, rigidité…In this work, we have been interested in blending wheat flour and poly(lactic acid). Wheat flour, which is mainly constituted of starch, has been transformed with plasticizers in a twin-screw extruder with the effect of heat and shear. Poly(lactic acid) is the main biodegradable polyester in the world nowadays. These two phases are thermodynamically immiscible and not very compatible, different ways are tried to improve the blend quality. A first part of this work lies on the search of optimal conditions to transform and blend the raw materials. Twin-screw extrusion is used to pasticize starch and to ensure a good blending between the two phases. Screw design and different equipments have been chosen for this purpose. Classical twin-screw parameters have been studied: screw design, temperature profile, filling ratio… The study of the formulation, more particularly of plasticizers for starch plasticization but also of compatibilizers to improve starch/PLA interphase is tackled in a second part. Citric acid is tested as a plasticizer but also as a compatibilizer. These researches have allowed to develop interesting formulations for industrial applications: possibility of processing by injection-molding, flexibility, rigidity…
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Uitterhaegen, Evelien. "Study of the integrated biorefinery of vegetable and essential oil in Apiaceae seeds." Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0045.
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Les fruits de coriandre ont été identifiés comme une source riche en huile végétale de haute qualité, à forte teneur en acide pétrosélinique et en huile essentielle. Un système d'extraction innovant a été conçu et développé en utilisant la technologie d'extrusion bi-vis. Il a permis l’obtention d'un produit nouveau, à savoir une huile végétale de coriandre aromatisée et à haute valeur ajoutée, d’un condensat présentant une concentration élevée en huile essentielle et d’un tourteau révélant une forte teneur en protéines. Le tourteau a montré son intérêt en tant que liant naturel pour la production de panneaux de fibres renouvelables issus de la paille de coriandre, un résidu de la culture de la plante, conduisant à des agromatériaux auto-liés et ayant un rapport performance/coût élevé. Les fibres de la paille de coriandre ont également présenté une bonne capacité de renforcement lorsqu’elles étaient utilisées comme charge naturelle dans des biocomposites thermoplastiques à base de polypropylène ou de biopolyéthylène, permettant le moulage par injection de matériaux peu couteux et aux propriétés mécaniques prometteuses. Ce travail présente ainsi une forte contribution à la mise en place d'une véritable bioraffinerie intégrée de la coriandre et à la démonstration de sa mise en oeuvre à une échelle industrielleCoriander fruits of French origin were identified as a rich source of a high-quality vegetable oil, with a high petroselinic acid content, and essential oil. An innovative extraction system was designed and developed using twin-screw extrusion technology and resulted in the recovery of a novel flavored coriander oil with high added value, as well as a hydrosol product with a high essential oil concentration and a press cake with an important protein fraction. The press cake was shown valuable as a natural binding agent for the production of renewable materials from coriander straw, a crop residue, and led to binderless boards with a high performance-cost ratio. Simultaneously, the coriander straw fibers displayed good reinforcing capacity as a natural filler in thermoplastic biocomposites from polypropylene or biopolyethylene, resulting in cost-effective materials with attractive properties. This work thus presents a strong contribution to the setup of a true integrated biorefinery for coriander fruits and its industrial implementation on a relevant production scale
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Renoux, Jennifer. "Elaboration par extrusion de mélanges de polymères et de nanocomposites biodégradables avec des protéines de soja isolées." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2018. http://www.theses.fr/2018MTLD0007.
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Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédicalVegetable isolated proteins are a renewable source of raw material, available in the large quantities. In spite of weak mechanical properties compared with the traditional polymers, they possess other important characteristics such as biodegradability, filmability and they are non-toxic. This study investigated the effect of processing type, compatibilization and addition of nanofillers on the properties of poly(butylene succinate-co-adipate)/plasticized isolated soy protein blends (PBSA/PISP). Initially, plasticizing and blending of soy protein with poly (butylene succinate-co-adipate) at various composition were carried out simultaneously in a single step extrusion. Then, the effect of adding poly(2-ethyl oxazoline) as compatibilizer has been studied. Addition of compatibilizer improves the interface and thermal properties of the blends. Besides, addition of halloysite nanotubes improves some mechanical and thermal properties. Finally, in the case of blend films prepared with equal PBSA/PISP composition (50/50), the compatibilizer increases the optical properties whereas addition of halloysite nanotubes improves the water vapour barrier properties and delay the degradation of blends as tested by soil buriel test. The overall results gives preliminary insights into potential usage of these films in packaging and possibly in biomedical sector
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Normand, Guillaume. "Nanocomposites à matrice polypropylène renforcée par argile lamellaire - Etude de la relation procédé-structure." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM053/document.
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Cette thèse porte sur la relation entre le procédé de préparation et la structure des nanocomposites polypropylène/argile. Les échantillons ont été préparés au mélangeur interne dans un premier temps. Des observations au microscope électronique à balayage, complétées par des analyses en diffraction des rayons X ainsi que des mesures rhéologiques ont permis de caractériser l’état de dispersion de l’argile à différentes échelles au sein du matériau. Nous avons comparé trois argiles organophiles et montré que la compatibilité chimique entre l’argile et la matrice est un facteur primordial afin d’obtenir une bonne dispersion : la Cloisite 20 et la Dellite 67G montrent de bons états de dispersion à toutes les échelles au contraire de la Cloisite 30B. Nous avons ensuite mis en évidence l’influence de la vitesse de rotation ainsi que du temps de mélange sur l’état de dispersion de l’argile. Le seuil de percolation de l’argile dans le polypropylène a été déterminé. Le lien entre état de dispersion et cristallinité du polypropylène a également été étudié.Les échantillons ont ensuite été préparés par extrusion bivis. L’influence de la vitesse de rotation sur l’état de dispersion de l’argile a été mise en évidence, tout autant que la dégradation de la matrice aux plus fortes vitesses. L’évolution de l’état de dispersion le long de la vis a montré que si l’intercalation était rapidement atteinte sur la vis, l’exfoliation progressait linéairement avant de saturer sur les dernières zones. L’utilisation d’une température de régulation plus faible ou d’une matrice plus visqueuse n’ont pas permis d’améliorer l’état de dispersion de l’argile ni d’éviter la dégradation de la matrice. Enfin, l’utilisation du logiciel Ludovic© a permis de mieux appréhender les phénomènes thermomécaniques mis en jeu lors de l’extrusion, mais également d’optimiser le procédéThis PhD focuses on the relationship between the preparation process and the structure of polypropylene/clay nanocomposites. First, the samples were prepared via an internal mixer. Scanning electron microscopy observations, completed by X-ray diffraction analysis and rheology measurements enabled us to characterize the clay dispersion state in the nanocomposite at different scales. Three organoclays were compared. It was shown that the chemical compatibility between the clay and the matrix was essential to ensure a good dispersion: Cloisite 20 and Dellite 67G showed good dispersion states at all scales, whereas Cloisite 30B did not. The influence of rotor speed and mixing time on the clay dispersion state was shown. The percolation threshold of the clay was determined. The link between dispersion state and crystallinity was also studied.The samples were then prepared via a twin-screw extruder. The influence of screw speed on the clay dispersion state was demonstrated, as well as the matrix degradation at high screw speed. The evolution of the dispersion state along the screw profile showed that intercalation was reached early in the screw profile, whereas exfoliation evolved linearly until the last mixing elements. A lower barrel temperature, as well as a more viscous matrix did not improve the clay dispersion state, and did not prevent the matrix degradation. Finally, the Ludovic© software allowed us to apprehend the thermomechanical phenomena involved during extrusion, but also to optimize the process
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Renoux, Jennifer. "Elaboration par extrusion de mélanges de polymères et de nanocomposites biodégradables avec des protéines de soja isolées." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2018. http://www.theses.fr/2018MTLD0007.
Full textAbstract:
Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédicalVegetable isolated proteins are a renewable source of raw material, available in the large quantities. In spite of weak mechanical properties compared with the traditional polymers, they possess other important characteristics such as biodegradability, filmability and they are non-toxic. This study investigated the effect of processing type, compatibilization and addition of nanofillers on the properties of poly(butylene succinate-co-adipate)/plasticized isolated soy protein blends (PBSA/PISP). Initially, plasticizing and blending of soy protein with poly (butylene succinate-co-adipate) at various composition were carried out simultaneously in a single step extrusion. Then, the effect of adding poly(2-ethyl oxazoline) as compatibilizer has been studied. Addition of compatibilizer improves the interface and thermal properties of the blends. Besides, addition of halloysite nanotubes improves some mechanical and thermal properties. Finally, in the case of blend films prepared with equal PBSA/PISP composition (50/50), the compatibilizer increases the optical properties whereas addition of halloysite nanotubes improves the water vapour barrier properties and delay the degradation of blends as tested by soil buriel test. The overall results gives preliminary insights into potential usage of these films in packaging and possibly in biomedical sector
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Ben, Said Anouar. "Purification de polyoléfines artificiellement polluées : études de l’extraction de composés modèles par CO2 supercritique en autoclave et en extrudeuse bi-vis." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES011.
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En raison de leurs excellentes propriétés, les polyoléfines telles que le polypropylène et le polyéthylène sont largement utilisées dans des applications d'emballage alimentaire. Cependant, tout au long de leur cycle de vie ou de la première utilisation, les polyoléfines peuvent être exposées à des milieux contaminés qui limitent leur recyclabilité en contact alimentaire. Par conséquence, le recyclage de polyoléfines au contact alimentaire nécessite des niveaux de décontamination rigoureux et donc une technologie de décontamination avancée. L’objectif de ce travail consiste dans un premier temps à étudier la faisabilité et la potentialité de l’extraction par CO2 supercritique en mode batch pour la purification de polyoléfines (extraction d’additifs et de contaminants modèles). On s’est plus particulièrement attaché à étudier l’effet des paramètres du procédé sur la cinétique de l’extraction ainsi que l’influence de l’extraction supercritique sur les comportements rhéologique et thermique des matériaux purifiés. Dans un deuxième temps, on s’est intéressé au développement d’un nouveau procédé continu d’extraction par couplage de l’extraction supercritique et l’extrusion bi-vis. Les résultats les plus importants ont montré la potentialité de l’extraction par CO2 supercritique en mode batch pour la purification de polyoléfines sans influencer significativement les propriétés de la matriceDue to their excellent properties, polyolefins such as polypropylene and polyethylene are widely used in food packaging applications to preserve and protect foodstuffs. However, throughout their lifecycle or first use, polyolefins can be exposed to contaminated media which limit their recyclability in food contact applications. Therefore, the recycling of polyolefins into direct food contact applications requires rigorous decontamination levels and thus effective and advanced recycling technology. The objective of this work is, at first hand, to study the feasibility and the potential of supercritical CO2 extraction in batch process for the purification of polyolefins (extraction of additives and model contaminants). In the whole, we investigated the effects of process parameters and contaminant structure on the extraction kinetic, and the influence of the supercritical CO2 extraction on the rheological and thermal behaviors of the purified materials. On the other hand, we aimed at the development of a novel continuous extraction process by coupling supercritical extraction technique and twin-screw extrusion. The most significant results showed the potential of supercritical CO2 extraction in batch mode for the purification of polyolefins without influence significantly the matrix properties
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Belyamani, Imane. "Développement d'un matériau thermoplastique biodégradable et hydrosoluble à base d'une protéine du lait." Phd thesis, Université Jean Monnet - Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-00702749.
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La biomasse représente l'une des principales alternatives à l'utilisation du pétrole dans la plasturgie. Grâce à leurs propriétés fonctionnelles, les caséinates sont une matière première prometteuse pour la fabrication de films plastiques pour des applications dans l'emballage biodégradable et hydrosoluble. La transformation du caséinate de sodium par les techniques habituellement utilisées dans la plasturgie a été démontrée. Des extrudats de caséinate plastifié au glycérol ont été obtenus au moyen d'une extrudeuse bi-vis corotative. La caractérisation physico-chimique du matériau obtenu a confirmé la thermostabilité de cette protéine et a montré la dépendance du comportement du matériau vis-à-vis de l'humidité ambiante. Pour une variation du taux d'Humidité Relative, de 40 à 90% et une augmentation de la concentration du glycérol, plastifiant hygroscopique, le matériau passe d'un état vitreux (rigide) à un état caoutchouteux (mou). Des films fins ont été ensuite réalisés, à partir des extrudats thermoplastiques, par extrusion gonflage. La perméabilité à la vapeur d'eau des films de caséinate de sodium a été étudiée et a montré que ces matériaux sont de mauvaises barrières à l'humidité. La deuxième partie a été consacré à l'étude de mélanges caséinate de sodium/caséinate de calcium d'un côté et caséinate de sodium/PBAT de l'autre. Le mélange des deux caséinates a permis d'augmenter la tenue mécanique du mélange, à partir de 50% de caséinate de calcium, et de retarder le transfert hydrique à travers le film. Dans le même sens, l'ajout du PBAT, a augmenté jusqu'à deux fois plus, le module d'Young des mélanges mais a baissé la résistance au transfert d'humidité du film à cause de l'incompatibilité des deux polymères.
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Gai, Jing-Gang. "Etudes théoriques et expérimentales de la processabilité du polyéthylène à ultra-haute masse molaire." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL039N/document.
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Aujourd’hui le développement de nouveaux matériaux polymères ayant de bonnes propriétés repose de plus en plus sur des procédés de mélange ou de compoundage de polymères au lieu de recourir à la synthèse de nouvelles molécules. L’action du mélange peut fortement influer sur la morphologie des matériaux polymères multi-constituants. Les extrudeuses bi-vis (TSE) sont souvent utilisées comme mélangeurs/réacteurs pour des procédés de mélange, de compoundage et d’extrusion réactive. Cependant, l’étude sur la qualité du mélange dans les TSE demeure un grand défi en raison de la complexité géométrique et du caractère transitoire de l’écoulement. Cette thèse a pour objet de développer un nouvel instrument en line pour mesurer en temps réel la distribution des temps de séjour (DTS) qui caractérise la performance du mélange axial et la capacité de convoyage de différents types d’éléments de vis basées sur l’analyse de l’écoulement transitoire et l’évaluation systématique de la théorie de mélange dans les TSE. Le mélange distributif des polymères fondus est caractérisé par la génération de l’aire des interfaces, un paramètre difficile à mesurer expérimentalement. Alors on fait appel à des simulations numériques de type CFDThe development of new materials with improved properties seems to rely nowadays more on blending and compounding than on the synthesis of chemically new polymers. Mixing may have a great effect on the morphology and structure of multi-component polymer materials. Twin-screw extruders (TSE) are widely used as mixers/reactors for blending, compounding, and reactive processing. This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) which characterizes the axial mixing and transport abilities of different screw elements based on the analysis of the transient flow pattern and systematic evaluation of mixing theory in TSE. Distributive mixing of polymer melts is characterized by the generation of interfacial area, which is experimentally much more difficult to measure. This 3D numerical simulation based on CFD is adopted
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Nascimento, Eduardo do. "ESTUDO DA DEGRADAÇÃO TERMOMECÂNICA E OXIDATIVA DA BLENDA POLIMÉRICA PEAD/PS." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2011. http://tede2.uepg.br/jspui/handle/prefix/1402.
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The degradation of polymer blends has been the subject of few scientific studies. Further studies are of great importance for understanding the degradation mechanisms in polymer blends. The degradation of the blend of HDPE / PS was studied as a function of their composition, processing temperature and number of processes. The material was extruded in a twin screw extruder co-rotacional interpenetrating at temperatures of 200, 240 and 280 ° C, reprocessed five times in the compositions of 25/75, 50/50 and 75/25 % (w.t) HDPE / PS, in addition to pure materials. An estimate of the distribution curve of molecular weight was made using data from parallel plate rheometry and degradation characteristics of the groups were analyzed by infrared spectroscopy with Fourier transformants. The results reveal two distinct regions of behavior in relation to the degradation of the blend. A domain with the mechanism of degradation of PS in which random chain scission occurs without the change in polydispersity, extending from pure PS to blend 50% HDPE / 50% PS. In this region the behavior is closer to the additivity of effects between the pure materials, tending to the field of mechanism of PS and greater balance between the mechanisms in that it increased the concentration of HDPE. It is inferred that this behavior go to about 40% of PS, where nearly co-continuity occurs between the phases. Another region is seen from the 75% HDPE blend. 25% PS to the pure HDPE, where the dominant mechanism is HDPE, with predominant chain branching and polydispersity increased at lower temperatures, in this case 200 ° C, and high rise of chain scission at higher temperatures, 280 ° C. In this region there is a synergistic effect towards the mechanism of HDPE, i.e. the addition of 25% of BP leads to a show very similar behavior to that of pure HDPE, distinguishing the effect of additivity. There is greater resistance to oxidation, synergistic effect, especially in the composition of 75% HDPE/PS 25% attributed to the dispersed morphology of the blends in this composition.
A degradação de blendas poliméricas tem sido alvo de poucos trabalhos científicos. Estudos mais aprofundados são de grande importância para o entendimento dos mecanismos de degradação em misturas de polímeros. A degradação da blenda PEAD/PS foi estudada em função da sua composição, temperatura de processamento e número de processamentos. O material foi extrudado numa extrusora dupla rosca corrotacional interpenetrantes nas temperaturas de 200, 240 e 280 °C, reprocessada cinco vezes nas composições de 25/75, 50/50 e 75/25 % (g/g) PEAD/PS, além dos materiais puros. Uma estimativa da curva de distribuição de massa molar foi feita através de dados de reometria de placas paralelas e os grupos característicos da degradação foram analisados por espectroscopia de infravermelho com transformada de Fourier. Os resultados revelam duas regiões de comportamentos distintos em relação à degradação da blenda. Uma com domínio do mecanismo de degradação do PS, no qual ocorre cisão aleatória das cadeias sem a variação da polidispersão, estendendo-se do PS puro até a blenda 50 % PEAD/ 50% PS. Nesta região o comportamento fica mais próximo à aditividade dos efeitos entre os materiais puros, tendendo para o domínio do mecanismo do PS e maior equilíbrio entre os mecanismos na medida em que é aumentada a concentração de PEAD. Infere-se que este comportamento siga até cerca de 40 % de PS, aproximadamente onde ocorre a cocontinuidade entre as fases. Outra região é vista a partir da blenda 75 % PEAD. 25 % PS até o PEAD puro, onde o mecanismo dominante é o do PEAD, apresentando preponderante ramificação de cadeia e aumento da polidispersão em menores temperaturas, neste caso 200 °C, e elevado aumento da cisão de cadeia em temperaturas maiores, 280 °C. Nesta região encontra-se um efeito sinérgico no sentido do mecanismo do PEAD, ou seja, a adição de 25 % de PS mostra conduz a um comportamento muito próximo ao de PEAD puro, distinguindo-se d efeito da aditividade. Há uma maior resistência à oxidação, efeito sinérgico, principalmente na composição 75 % PEAD. 25 % PS atribuído à morfologia dispersa da blenda nessa composição.
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Nguyen, Quang Hung. "Study on bioaccumulation and integrated biorefinery of vegetable oil and essential oil of Coriander (Coriandrum sativum L.)." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/16038/1/Nguyen_QH.pdf.
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Apiaceae could be defined as Aroma Tincto Oleo Crops (ATOC), e.g. plants containing both vegetable oil and essential oil. Applying agroreffinery concept to ATOC led to propose a sequential fractionation process coupling co-extraction of vegetal oil and essential oil to a valorization of by-product residues as biosourced active molecules and substrates for designing agromaterials. The aim of this thesis is to determine the biological and technological feasability of application of the ATOC-refinery concept to coriander (Coriandrum sativum L.) Chapter I reports a bibliographic state of the art study on extraction and characterisation of coriander vegetal oil and essential oil while chapter II describes materials and methods setting up during the thesis for sampling, extraction, analysis and data processing. Chapter III focus on the study of major various biological parameters influencing bioaccumulation of vegetal oil and essential oil in coriander (different plant varieties, different plant organs, different biological stages) and their impact on anti-oxidant activity of extracts obtained from extraction residues. In chapter IV, coriander fruits are processed by extrusion technology (mono screw and twin-screw extruder) in order to evaluate the feasability of mechanical pressing for extracting a flavored vegetal oil. Influence of operating parameters on vegetal oil extraction yields (nozzle diameter and nozzle/screw distance (single-screw extruder) or screw configuration, device’s filling coefficient and pressing temperature (twin-screw extruder)) is studied while the feasability of valorization of extraction cake as agromaterial (thermopressing) was stated.
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Banu, Ionut. "Modeling and optimization of tubular polymerization reactors." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00719401.
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The aim of this thesis is the investigation of modeling and optimization particularities of tubular polymerization reactors. The original work is divided in two sections, the first treating a modeling and optimization study of tubular reactors for methyl methacrylate polymerization in solution, and the second, an experimental and theoretical study of L-lactide reactive extrusion. In the first section, reactor simulations in similar operating conditions were performed in order to select a representative kinetic model among the published kinetic models for MMA solution polymerization. Two widely used numerical algorithms, one based on Pontryagin's Minimum Principle and the other a Genetic Algorithm, were compared for an average-complexity optimization problem. The results showed a superior robustness of the Genetic Algorithm for this category of problems. The second part of the thesis deals with the modeling and optimization of L-lactide reactive extrusion. A kinetic model is proposed and its parameters estimated using nonlinear estimation numerical procedures based on experimentally measured data. Reactive extrusion experiments were performed in representative operating conditions. The Llactide/ polylactide flow in the extruder was characterized by simulation using the commercial software LUDOVIC®. The simulated residence time distributions characteristics are used to model the reactive extrusion process of two approaches, an axial dispersion model and a compartment model, based on compartments whose characteristics are deduced from the simulations using LUDOVIC®. The modeling results are in good agreement with the measured data in the same operating conditions.
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Ji, Wei-Yun. "Développement d'un concept d'agent compatibilisant-traceur réactif visant à étudier l'évolution de la réaction interfaciale et de la morphologie de mélanges de polymères réactifs." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0247/document.
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Le mélange de polymères est une méthode répandue pour élaborer des matériaux polymères. Cependant, la plupart des polymères sont thermodynamiquement immiscibles entre eux, engendrant une séparation de phase des mélanges et une détérioration de leurs propriétés. Afin de palier ces problèmes, la méthode dite compatibilisation réactive est souvent employée. Elle est basée sur la formation in-situ de copolymères à bloc ou greffés par l’intermédiaire de réactions interfaciales entre polymères réactifs. Cette thèse a pour objet de développer un concept dit agent compatibilisant-traceur réactif qui permettra d’utiliser de faibles quantités d’agents compatibilisants réactifs pour évaluer leurs efficacités de compatibilisation directement sur des extrudeuses bi-vis industrielles, d’une part ; et de caractériser la performance du mélange d’une extrudeuse bi-vis en fonction des conditions opératoires et/ou du profil de vis employé. Ses principales contributions se résument ci-après. L’anthracène de 9-méthylaminométhyle (MAMA), une molécule fluorescente, est incorporée dans un copolymère statistique de styrène (St) et d’isocyanate de 3-isopropenyle-?, ?’-diméthylebenzène (TMI), noté PS-TMI, pour former un agent compatibilisant-traceur réactif, noté PS-TMI-MAMA. Ce dernier sert à la fois comme agent compatibilisant réactif grâce aux groupements isocyanate et traceur grâce aux groupements fluorescents. Il est utilisé pour les mélanges à base de polystyrène (PS) et de polyamide 6 (PA6) afin d’évaluer son efficacité de compatibilisation. Les mélanges PS/PA6 sont élaborés dans un mélangeur discontinu et une extrudeuse bi-vis, respectivement. Dans le cas du mélangeur discontinu, la quantité du copolymère greffé formé in-situ, noté PS-g-PA6-MAMA, augmente alors que le diamètre des domaines de la phase dispersée (DDD) diminue considérablement au début du mélange. Lorsque le mélange se poursuit, le nombre de greffons en PA6 du PS-g-PA6-MAMA augmente, engendrant une composition très asymétrique du PS-g-PA6-MAMA qui est thermodynamiquement instable aux interfaces. De ce fait, il peut être arraché des interfaces vers la phase PA6 et peut y former des micelles. Lorsqu’il est arraché des interfaces, il perdra son efficacité de compatibilisation et le DDD augmentera. L’action du mélange a un double effet sur le procédé de compatibilisation réactive. Il promeut la réaction interfaciale entre le PS-TMI-MAMA et le PA6, d’une part ; et aggrave l’arrachage du PS-g-PA6-MAMA de l’interface, d’autre part. L’utilisation de faibles quantités de l’agent compatibilisant-traceur réactif permet de mesurer les évolutions de la teneur en agent compatibilisant-traceur réactif, du DDD et de la teneur en agent compatibilisant-traceur réactif ayant réagi en fonction du temps de séjour dans une extrudeuse bi-vis. Pour une masse molaire donnée, l’efficacité de compatibilisation d’un agent compatibilisant-traceur réactif augmente avec l’augmentation de la teneur en TMI dans une certaine limite. Pour une teneur en TMI donnée, la réaction interfaciale est plus rapide avec la diminution de la masse molaire dans une certaine limite et le DDD devient plus petit en un temps plus court. L’influence du taux de remplissage de la vis est plus significative que celle du temps de séjour. Lorsque le taux de remplissage de la vis augmente, le taux de la réaction interfaciale augmente et le DDD diminue. Lorsque l’angle d’un élément de mélange augmente, les efficacités du mélange distributif et du mélange dispersif augmentent, ce qui se traduit par une augmentation de la quantité du PS-g-PA6-MAMA formée et une diminution du DDD par rapport à la même quantité de PS-g-PA6-MAMA produite. Lorsque la largeur d’un élément de mélange augmente, l’efficacité du mélange distributive augmente alors que celle du mélange dispersif demeure inchangée. La substitution d’éléments de mélange par des éléments inverses améliore l’efficacité du mélange distributif et celle du mélange dispersifPolymer blending is a common method to prepare high-performance polymer materials. However, most polymer pairs are thermodynamically immiscible, leading to phase separation and deterioration in material properties. To overcome such problems, the most common method is reactive compatibilization which is based on the in-situ formation of a graft or block copolymer by interfacial reaction between reactive polymers. This thesis aims at developing a concept of reactive compatibilizer-tracer which will allow using small amounts of reactive compatibilizers to evaluate their compatibilizing efficiency in industrial scale twin screw extruders, on the one hand; and to characterize the mixing performance of a twin screw extruder as a function of process conditions and/or screw profile. Its main contributions are summarized below. 9-(methylaminomethyl) anthracene (MAMA), a fluorescent molecule, is incorporated into a random copolymer of styrene (St) and 3-isopropenyl-?, ?’-dimethylbenzene isocyanate (TMI), denoted as PS-TMI, to form a reactive compatibilizer-tracer, denoted as PS- TMI-MAMA. The latter serves both as a reactive compatibilizer due to its isocyanate moieties and a tracer due to its fluorescent moieites. It is used for polystyrene (PS)/polyamide 6 (PA6) blends to evaluate its compatibilizing efficiency. Compatibilized PS/PA6 blends are processed in a batch mixer and in a twin screw extruder, respectively. In the case of the batch mixer, the amount of the in-situ formed graft copolymer denoted as PS-g-PA6-MAMA increases and the dispersed phase domain diameter (DDD) decreases drastically in the initial period of mixing. As the mixing further proceeds, the number of PA6 grafts of the PS-g-PA6-MAMA increases, resulting in a highly asymmetrical composition of the PS-g-PA6-MAMA which causes thermodynamic instablility at the interface. As a result, it could be pulled out of the interface to the PA6 phase and form micelles. Once it is pulled out of the interface, it will lose its compatibilizing efficiency and the dispersed phase domain diameter increases sharply. Mixing has a dual effect on the reactive compatibilization process. On the one hand, it promotes the interfacial reaction between the PS-TMI-MAMA and PA6. On the other hand, it aggravates the pull out of the resulting PS-g-PA6-MAMA from the interface. The use of small amounts of the reactive compatibilizer-tracer together with transient experiments for RTD allows assessing the evolutions of the reactive compatibilizer-tracer content (CC), the dispersed phase domain diameter (DDD), and the reacted reactive compatibilizer-tracer content (RCC) as a function of residence time in a twin-screw extruder. Based on the above results, the emulsification curve (DDD vs. CC), the RCC vs. CC curve and effective emulsification curve (DDD vs. RCC) are obtained. When the molar mass of the reactive compatibilizer-tracer is fixed, its compatibilizing efficiency increases with increasing TMI content within an appropriate range. When its TMI content is fixed, the interfacial reaction goes faster as the molar mass of the reactive compatibilizer-tracer decreases within a certain range, and the DDD becomes smaller in a shorter time. The effect of degree of fill fixed by the throughput Q/screw speed N ratio is more dominant than that of residence time. As the degree of fill increases, the interfacial reaction increases and the DDD decreases. As the angle of adjacent the kneading block increases, its distributive and dispersive mixing efficiencies increase, resulting in an increase in interfacial area generation and a decrease in DDD on the basis of the same amount of PS-g-PA6-MAMA. On the other hand, as the width of the kneading block increases, the distributive mixing efficiency increases and the dispersive mixing efficiency remains unchanged. Substitution of kneading blocks by reverse ones increase both the distributive and dispersive mixing efficiencies
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Fel, Elie. "Mise en oeuvre de mélanges de polyoléfines compatibilisées par ajout de copolymères ou à l'aide d'irradiation gamma : Caractérisation d'espèces réactives par Résonance Paramagnétique Electronique (RPE)." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0049/document.
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Des procédés innovants basés sur l’extrusion à haute vitesse et l’irradiation sous rayonnement γ, ont été étudiés en vue d’améliorer la compatibilisation de deux polyoléfines non miscibles : le polypropylène PP et le polyéthylène PE. Dans un premier temps, l’étude de la distribution des temps de séjour de polypropylènes dans l’extrudeuse à haute vitesse a été réalisée. L’impact des conditions opératoires (débit et vitesse de rotation des vis) ainsi que l’impact du profil de vis et de la viscosité du polypropylène d’étude ont été mis en avant. Certains résultats expérimentaux sont souvent en accord avec ceux du logiciel de simulation d’extrusion bi-vis Ludovic, bien qu’il puisse y avoir des écarts pour les hautes vitesses de rotation des vis. Dans un deuxième temps, une fois l’écoulement caractérisé, nous avons réalisé des mélanges PP/PE, les paramètres qui ont varié sont la quantité d’énergie apportée durant le mélange (vitesse de rotation des vis) ainsi que la présence ou non de copolymère préformé et le type d’atmosphère utilisée durant l’extrusion. Faire varier le taux de cisaillement ne permet pas la modulation des propriétés finales du mélange surtout lorsque l’on extrude sous atmosphère inerte. L’utilisation de copolymère préformé, de type éthylène-octène, permet d’améliorer considérablement les propriétés de notre mélange en créant une interphase "cœur-couronne" entre la matrice PP, le compatibilisant et la phase dispersée PE. Pour terminer, une étape d’irradiation γ a été ajoutée au procédé de mise en œuvre classique de nos mélanges. En première partie de cette étude, la simulation de spectres RPE a permis d’identifier et quantifier les différentes espèces radicalaires créées. Dans la deuxième partie, l’influence de la place de la séquence d’irradiation a été étudiée : avant extrusion, entre extrusion et injection, après injection et avant recuit. Les meilleures améliorations ont été obtenues lorsque l’irradiation est suivie d’un traitement thermique. En conclusion, il est possible d’améliorer la compatibilité d’un mélange PP/PE en jouant essentiellement sur l’ordre des étapes de production sans avoir à modifier la formulation de ce dernierInnovative processes, based on high shear twin screw extrusion and γ-irradiation, have been used to increase the compatibility of two immiscible polyolefins: polypropylene PP and polyethylene PE. In a first part, the residence time distribution of polypropylenes in the twin screw extruder (TSE) has been investigated. The impact of the processing conditions (throughput and screw rotation speed), the screw profile and the polypropylene viscosity were underlined. Some of the experimental results are often in good agreement with those predicted by simulation software of twin screw extrusion (Ludovic), except for some experiments at high screw rotation rates. In a second part, once polymer flow was characterised in the TSE, we realized PP/PE blends. The impact of the mechanical energy (screw rotation speed), the presence or absence of copolymers and the nature of the extrusion atmosphere were analysed. Using high shear rate does not allow modulating the final properties of the blends particularly once inert atmosphere is used. The use of ethylene-octene copolymers increases significantly the final properties of the PP/PE blends by creating a “core-shell” morphology between the PP matrix, the copolymer and the PE dispersed phase. To finish, a γ-irradiation process step has been added to the classical processing of PP/PE blends. In a first part of this study, the simulations of ESR spectra have permitted to identify and quantify the different radicals created. In a second part, the sequence order of the γ-irradiation has been investigated: before extrusion, between extrusion and injection, and after injection followed by a thermal treatment. The best results were obtained once γ-irradiation is followed by a heat treatment. As a conclusion, the compatibility of immiscible polyolefins can be improved only by changing the order of the different processing steps without changing the formulation
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Danda, kranthi Chaitanya. "Processing-Structure-Property Relationships in Polymer Carbon Nanocomposites." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case156217449277816.
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Evon, Philippe. "Nouveau procédé de bioraffinage du tournesol plante entière par fractionnement thermo-mécano-chimique en extrudeur bi-vis : étude de l'extraction aqueuse des lipides et de la mise en forme du raffinat en agromatériaux par thermomoulage." Phd thesis, Toulouse, INPT, 2008. http://oatao.univ-toulouse.fr/7723/1/evon.pdf.
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L'extraction aqueuse des lipides de la graine de tournesol est étudiée en contacteur agité. La diffusion à l'intérieur des particules est le facteur limitant de l'échange de matière. Les protéines sont impliquées dans l'entraînement et la stabilisation des lipides par l'eau. Le fractionnement de la plante entière est également étudié avec l'eau en extrusion bi-vis. Un extrait et un raffinat sont obtenus séparément et en une seule étape continue. Des rendements d'extraction en huile de 55 % peuvent être obtenus sous forme d'émulsions huile/eau. Leur stabilité est assurée par la présence à l'interface de tensioactifs : les phospholipides et les protéines voire les pectines. Les extraits se composent aussi d'une phase hydrophile. Prépondérante, elle contient des composés hydrosolubles (protéines, pectines…). Riches en fibres, les raffinats présentent une teneur significative en protéines au comportement thermoplastique. Ils peuvent être transformés en agromatériaux par thermomoulage.
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Abdillahi, Houssein. "Propriétes barrière et mécaniques d'agromatériaux thermoplastiques à base de farine de blé et de polyesters biosources et biodégradables." Thesis, Toulouse, INPT, 2014. http://www.theses.fr/2014INPT0027.
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Des produits de consommation de première nécessité aux produits les plus fortuits, l'emballage, en particulier plastique, constitue aujourd'hui un élément indispensable de notre vie quotidienne. Son utilisation intensive dans le domaine agroalimentaire pour un usage unique à courte durée de vie incite aujourd'hui à s'orienter vers de nouveaux matériaux d'origine renouvelable et biodégradables, aux caractéristiques similaires que leurs homologues issus des ressources fossiles. Les mélanges à base de biopolymères et de biopolyesters peuvent être une bonne alternative. Dans ce présent travail de thèse, des mélanges de farine de blé, thermoplastifiée par du glycérol et de l'eau, et des polyesters biosourcés et biodégradables tels que le PLA et/ou le PHB ont été obtenus par extrusion bivis et moulés par injection thermoplastique. Les caractéristiques thermiques, thermomécaniques dynamiques, morphologiques, mécaniques et barrières de ces nouveaux matériaux ont été étudiés. De l'acide citrique a été utilisé comme agent de compatibilisant pour améliorer l'interface amidon/PLA. Les différentes investigations nous ont permis de mettre au point différents types de formulations aux caractéristiques mécaniques et barrières à la vapeur d'eau intéressantes pour la fabrication de corps de barquettes d'emballage alimentaire de denrées périssables comme la viande ou les fromages. L'aptitude au contact alimentaire des matériaux farine thermoplastifiée/polyester et l'impact de l'incorporation des polyesters sur la biodégradabilité de ces matériaux ont également été étudiésFrom basic and essential to unnecessary and optional consumer products, packaging, particularly plastic, is today an indispensable part of our daily life. Its extensive use in the food industry for a single use and for a short shelf-life encourages us today to move towards new renewable and biodegradable materials with similar characteristics than their counterparts from fossil resources. Biopolymers and biopolyesters blends can be a good alternative. Within the framework of this present work, wheat flour, thermoplasticised by glycerol and water, and biobased and biodegradable polyesters such as PLA and/or PHB, were blended using an industrial twin screw extruder and were injection-molded into thermoplastic materials. Thermal, dynamic thermomechanical, morphological, mechanical and barriers properties of these new materials were studied. Citric acid was used as a compatibilizer to improve the interface starch/PLA. The different investigations have allowed us to develop various types of formulations, with mechanical characteristics and barrier properties to water vapor, very attractive for manufacturing plastic food packaging which can be used for meats or cheeses. Food contact suitability and biodegradability of thermoplasticised wheat flour/polyester materials have also studied
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Dergham, Nora. "Mise en oeuvre de biocomposites Poly(acide lactique)/Bioverres : Relation structure/ rhéologie/procédés de mise en forme." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0086.
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Le travail présenté porte sur la rhéologie, la mise en forme et la caractérisation de matériaux biocomposites de nouvelles générations pour des applications orthopédiques. Dans le cadre de cette étude, des biocomposites poly (D,L-lactide) (PDLLA)/bioverres ont été élaborés par extrusion bivis sous atmosphère inerte. Les bioverres différent par la nature de leur traitement thermique et leur morphologie. La première partie a été consacrée à l’étude de l’état de la dispersion des bioverres dans la matrice polymère. Nous avons montré que l’homogénéité de cette dispersion dépend, d’une part de la structure, de la morphologie, du taux volumique des charges et d’autre part des paramètres du procédé (cisaillement, température,…). Le comportement rhéologique des suspensions a été étudié à l’état fondu ainsi qu’à l’état solide. Un accent particulier a été porté sur l’étude de l’influence du taux des bioverres, de leur taille moyenne et plus particulièrement de leur traitement thermique. Les masses molaires de PDLLA extrait des composites élaborés ont été évaluées par chromatographie d’exclusion stérique (CES). Enfin, la qualité de la dispersion des charges, en termes de distance inter-particulaire et taille moyenne, a été étudiée par microscopie électronique à balayage (MEB) et analyses d’image. Il a été montré que l’utilisation de bioverres non traités thermiquement lors de la mise en forme de composites à haute température provoque la dégradation de la matrice. Aussi, on assiste à une réduction des masses molaires. Les propriétés viscoélastiques et les propriétés mécaniques sont altérées à leur tour. Cette dégradation a été étudiée par spectroscopie infrarouge (IRTF) et par analyse thermogravimétrique (ATG). Les origines et mécanismes sous-jacents de cette dégradation ont été proposés. Il est démontré pour la première fois que la présente dégradation du PDLLA peut être atténuée par l’emploi de différentes charges céramiques à propriétés spécifiques. En outre, l’utilisation de ces bioverres a permis l’obtention d’une dispersion homogène au sein de la matrice. L’analyse des propriétés rhéologiques de tels matériaux et leur modélisation a permis de mettre en évidence les interactions matrice-charges. La deuxième partie de l’étude a porté sur l’élaboration des biocomposites multicouches à gradient de propriétés par coextrusion. Ces multicouches présentent, d’une part, des propriétés variables selon le type de traitement et de composition du bioverre actif. D’autre part, le gradient de propriété a été également réalisé en faisant varier les paramètres expérimentaux relatifs au procédé de coextrusion. Les matériaux finaux, ainsi obtenus, présentent de très bonnes propriétés cohésives avec une bioactivité maîtrisée et contrôléeBioactive and biodegradable composites have gained increasing importance in the orthopedic field as bone replacement materials and as scaffolds for tissue engineering. In this study, biocomposites based on poly(D,L-lactide) (PDLLA) and bioactive glass fillers were prepared by a twin screw extrusion under Argon inert gas with various filler contents, thermal treatments and particle sizes. The processing conditions were monitored to produce composites with well controlled physico-chemical, mechanical and dispersive properties. The aim of the present work is to gain a fundamental understanding of the relationships between structure, processing conditions and final properties of these biocomposites. The dispersion state of fillers was characterized by SEM. It was highlighted that the inclusion of non treated bioglass in PDLLA under elevated temperatures resulted in a decrease of molar mass. This degradation of the matrix leads to a reduction of the viscoelastic and mechanical properties of the composites. The origin and mechanisms of this degradation were probed using a Fourier Transform Infrared (FTIR) spectroscopy. The optimization of their processing allows a better control of this drastic loss of properties. Furthermore, the demonstration had been done that the present degradation of PDLLA matrix can be attenuated using a different glass ceramics with a special size and thermally treated. The rheological behaviour in linear and non linear viscoelasticity of the controlled PDLLA/BG suspensions has been assessed in both solid and molten state. Hence, their experimental rheological behaviour was compared to the theoretical suspension models. Finally, the effects of volume fraction, particle size and thermal treatment on the mechanical properties have been also investigated and discussed. The obtained results corroborate the rheological and physic-chemical ones. Finally, the multilayer structures with various amounts and treatments of BG fillers were obtained by a designed scale lab coextrusion machines. The gradient of properties has been obtained and improved cohesion properties between the neighboring were highlighted. Their bioactivity was finally demonstrated. At last, no residual stress inside the multilayers can be observed. This observation explains the conservation of the initial shape of those implants, without nor deformation neither relaxation, during the simulation of the chirurgical implantation in SBF
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Theng, Dyna. "Feasibility of incorporating treated lignin and cellulose nanofiber in fiberboards made from corn stalk and rice straw." Doctoral thesis, Universitat de Girona, 2017. http://hdl.handle.net/10803/461717.
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Agricultural waste is of particularly interest due to abudant, cheap, widely available worldwide and renewable material. It represent a good option for wood sources substitution, containing similar in chemical and physical characteristics. The present Doctoral Thesis studies the possibility of substituting wood sources by crop residues and replacing synthetic binders by natural adhesives in fiberboard production. Corn and rice biomass were selected as raw materials, followed by thermo-mechanical pulping (TMP) pretreatment. Fiberboards made of TMP of both crop residues without any binder presented lower mechanical properties than commercial ones (which contained synthetic binder). In term of physical properties, lower water absorption and thickness swelling were found for the fiberboards made of crop residues than for the commercial one. Overall, the present study shows a more sustainable and effective way of producing cellulose-based fiberboards without aid of any synthetic binder, contributing thus to both technical and environmental aspects of fiberboard manufacturingEls residus agrícoles tenen un gran interès per ser un material abundant , barat, àmpliament disponible a tot el món i renovable. Es tracta d'una bona opció per substituir la fusta, i presenta característiques físiques i químiques similars a aquesta. La present tesi doctoral estudia la possibilitat de substituir la fusta i els aglutinants sintètics per residus de cultius i adhesius naturals respectivament en la producció panell de fibres. La biomassa de blat de moro i arròs sotmesa a un tractament termomecànic (TMP)es va seleccionar com a matèria primera. El panell de fibra resultant d'ambdós residus sense cap tipus d'aglutinant presentaven propietats mecàniques més baixes que els panells comercials (que contenien un lligant sintètic). Respecte a les propietats físiques, es va observar un augment de volum i espessor al absorbir aigua menors en el panell de fibres naturals que no pas en els comercials. En general, el present estudi mostra una forma més sostenible i efectiva de produir panells de fibra a base de cel·lulosa sense utilitzar aglutinant sintètic, fet que contribueix a la millora d’aspectes tècnics i ambientals en el procés de fabricació dels panells de fibra
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CHEN, HUI-HUANG, and 陳輝煌. "Optimized twin-screw extrusion of expanded rice." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/80143066897792104772.
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