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1
Mattlet, Agnès. "Influence de l'utilisation d'une matrice recyclée sur le comportement et les performances d'un composite lin/polypropylène lors de sa mise en oeuvre et de son vieillissement hydrothermique." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2022. http://www.theses.fr/2022UBFCK079.
Повний текст джерелаАнотація:
Afin de répondre à l'intérêt grandissant autour de l'écologie, le développement de matériaux éco-responsables est devenu prépondérant dans des domaines tels que les transports et la mobilité. Le remplacement des fibres synthétiques par des fibres naturelles et des polymères vierges par des recyclés sont des solutions potentiellement intéressantes. En effet, ces matériaux présentent des propriétés mécaniques spécifiques similaires et une empreinte environnementale plus faible. Néanmoins, les fibres naturelles présentent une forte hydrophilie, ce qui peut poser problème lors d'une utilisation à long terme en extérieur. Les polymères quant à eux subissent des modifications lors de leur recyclage qui peuvent affecter leur compatibilité avec les fibres. L'objectif de cette thèse est d'étudier comment l'utilisation d'une matrice recyclée influe sur les propriétés d'usage de composites polypropylène/lin et sur leur comportement lors de vieillissements hydrothermiques et cycliques. Dans un premier temps, l'influence des paramètres de mise en œuvre (pourcentage d'agent compatibilisant, temps, température et pression de consolidation, vitesse de refroidissement et température de sortie du moule) sur les propriétés mécaniques des composites à matrice vierge a été étudiée afin d'obtenir un matériau de référence. Ensuite, l'impact de l'utilisation de matrices recyclées sur les propriétés du composite a été étudiée. Enfin, des vieillissements hydrothermiques et cycliques (immersion, gel, séchage) ont été appliqués aux différents composites (matrices vierges et recyclées). Une analyse multi-échelle conjuguant caractérisations physico-chimiques, structurales et mécaniques a été réalisée au cours du vieillissement afin de mieux comprendre l'effet de matrices recyclées sur le comportement dans le temps des compositesTo respond to the growing interest in ecology, the development of eco-responsible materials has become preponderant in areas such as transportation and mobility. One potential solution is to replace synthetic fibers by natural ones and virgin polymers by recycled ones. Indeed, these materials present similar specific properties and a lesser environmental footprint. However, natural fibers are very hydrophilic, which can be a problem in long-term outdoor use. As for the polymers, they undergo modifications during recycling that can affect their compatibility with fibers. This thesis' aim is to investigate how the use of a recycled matrix affects the properties of polypropylene/flax composites and their behavior under hydrothermal and cyclic ageing. First, the influence of processing parameters (compatibilizing agent's percentage, consolidation time, temperature and pressure, cooling rate and exit temperature) on the mechanical properties of virgin matrix composites was studied in order to obtain a reference material. Then, the impact of the use of recycled matrices on the properties of the composite was studied. Finally, hydrothermal and cyclic ageing (immersion, freezing and drying) were applied to all composites (with virgin and recycled matrices). A multiscale analysis combining physicochemical, structural and mechanical characterizations was carried out during ageing to better understand the influence of the matrix on the behavior of the composites over time
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Achtioui, Touria. "Mise en œuvre et caractérisation de matériaux polymères issus d' emballages plastiques recyclés." Thesis, Reims, 2014. http://www.theses.fr/2014REIMS036.
Повний текст джерелаАнотація:
L'objectif de cette thèse fut de comprendre les mécanismes de dégradation des SAN et des ABS à partir de déchets de rebuts de production bruts et/ou chargés de la société Albéa (anciennement connue sous le nom d'Alcan Packaging). Ce projet devrait permettre de répondre à des exigences en termes de diminution de volume de déchets, d'amélioration de propriétés et de diminution de coûts. Ce travail permettra également d'améliorer notre compréhension sur des aspects fondamentaux de recyclabilité physique des polymères lors de différents cycles en injection moulage. L'étude au mélangeur interne a permis de mettre en évidence les phénomènes de dégradation sous l'influence des conditions de mise en œuvre (vitesse, température et temps de mélange). Ainsi, dans le cas du SAN, les mécanismes de la dégradation thermo-mécanique sont générés à la fois par la thermo-oxydation et par la dégradation mécanique impliquant des coupures de chaînes. Dans le cas des ABS, les mécanismes de dégradation thermo-mécanique mis en jeu impliquent, outre les sites chromophores, plusieurs réactions en compétition comme la réticulation et les coupures de chaîne. L'originalité de cette étude réside dans la mise en évidence expérimentale, à travers des techniques originales (TMDSC, RMN du solide, AFM), d'un mécanisme théorique de dégradation des SAN et des ABS en se plaçant dans les conditions réelles de mise en œuvre. Nous avons alors pu mettre en évidence la réelle contribution de l'effet thermique et de l'effet du cisaillement qui jusqu'alors, dans la littérature, semblait non étudié. Finalement, les effets de dégradation du SAN n'ont pas affecté les propriétés mécaniques bien qu'une décoloration et une diminution de la viscosité aient été observées. En revanche, dans le cas de l'ABS recyclé, les propriétés en traction et la résistance au choc ont considérablement été affectées, notamment par la présence de vernis qui interfère sur le transfert de contraintes entre les nodules de PB et la matrice SANThe aim of this PhD thesis was to understand the mechanisms of degradation of SAN and ABS from waste sprues and undelivered packages from Albea Group (formerly known as Alcan Packaging). The results of this project should allow the reduction of waste volume, the improvement of material properties and a costs reduction. The present workshould also improve the understanding of the fundamental aspects of physical recyclability of polymers during different cycles in injection molding.The first part of the study performed using an internal mixer showed how degradation was influenced by processing parameters such as the rotor speed, the temperature and the mixing time. Thus, considering the SAN, the mechanisms of the thermo-mechanical degradation are both generated by the thermo-mechanical degradation and by the oxidation that involves chain scissions. In the case of ABS, its mechanisms of thermo-mechanical degradation imply further chromophores sites, several competition reactions such as crosslinking and chain scissions.The innovative feature of our work was to establish a theoretical mechanism of degradation of ABS and SAN under processing conditions used in industry thanks to our experimental approach with original investigation procedure (TMDSC, solid state NMR, AFM). Afterwards, we were then able to identify the real contribution on the one hand of the shearing effect, which seemed still unstudied in the literature, and of the other hand of the thermal effect.Finally, it was found that degradation was not affecting SAN mechanical properties whereas discoloration and a reduction of viscosity were observed. On the opposite, the recycling of ABS resulted in a significant reduction of tensile properties and the impact strength due to the presence of varnish which interfered in stress transfer between PB nodules and the SAN matrix
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Cabrera, Alvino Géraldine. "Eco-design and processing of recycled multilayer/multiphase polymer materials : Structure-properties-process relationship." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI076.
Повний текст джерелаАнотація:
Dans un contexte d’économie circulaire, les premiers travaux de la thèse ont été consacrés à l’étude de l’aptitude à la mise en forme de films souples recyclés provenant de déchets agricoles d’enrubannage et d’horticulture. Ces films multicouches contiennent initialement un additif conférant au produit final un caractère collant. Lors de leur recyclage, cet additif est toujours présent et migre à la surface. Un accent particulier a été dédié à la compréhension et l’étude des mécanismes de migration de cet additif en fonction de l’architecture moléculaire des polyéthylènes utilisés ayant des taux de branchements différents. Pour ce faire, des mélanges modèles, avec ou sans charges minérales, ont été élaborés. Outre des études morphologiques et microstructurales, des méthodologies expérimentales originales ont été mises en place pour étudier la cinétique de migration/diffusion avec des dispositifs tribo-rhéométriques et de suivi du "tack" en surface des films. Quant au comportement rhéologique en cisaillement et en élongation, il est influencé par la présence de cet additif. La deuxième partie de cette étude a été consacrée à l’appréhension des réalités de l’activité du recyclage d’autres films mutlicouches souples à base de polypropylène et polyéthylène. Compte tenu de la complexité de ces gisements, nous avons choisi d’étudier des mélanges modèles équivalents en leur associant des compatibilisants de nature physique. L’influence de ces derniers sur les propriétés rhéologiques, morphologiques et mécaniques a été ensuite évaluée. Cette étude a été ensuite transposée à des systèmes multiphasés post usage. Les derniers travaux ont été dédiés à une approche prospective. Il s’agit d’aller de l’éco-design à l’élaboration de multi-micro/nanocouches facilement recyclables. L’originalité de cette étude consiste à limiter le nombre de constituants, à réduire/contrôler les épaisseurs des couches et éviter l’utilisation des couches de liants. Enfin, leurs propriétés rhéologiques, morphologiques et mécaniques ont été évaluées en fonction des cycles de recyclage mécaniqueIn the context of a circular economy, the first works of the thesis were devoted to the study of the processing ability of recycled flexible films from agricultural bale wrapping film's waste. These multilayer films initially contain an additive that gives the final product a sticky character. During recycling, this additive is still present and migrates to the surface. A particular emphasis has been placed on understanding and studying the migration mechanisms of this additive according to the molecular architecture of the polyethylenes used with different branching content. Model blends, with or without mineral fillers, were prepared for this purpose. In addition to morphological and microstructural studies, original experimental methodologies have been set up to study the migration/diffusion kinetics with tribo-rheometry and film surface's "tack" monitoring devices. As for the rheological behaviour in shear and elongation, it is influenced by the presence of this additive. The second part of this study was devoted to understanding the realities of the recycling activity of other polypropylene- and polyethylene-based multilayer films. Given the complexity of these materials, we chose to study equivalent model blends by combining them with physical compatibilizers. The influence of the latter on the rheological, morphological and mechanical properties was then evaluated. This study was then transposed to postconsumption multiphase systems. The last studies were devoted to a future-oriented approach. This involves going from eco-design to the development of easily recyclable multimicro/ nanolayers. The originality of this study consists in limiting the number of constituents, reducing/controlling the thickness of the layers and avoiding the use of tie-layers. Finally, their rheological, morphological and mechanical properties have been evaluated according to number and type of mechanical recycling cycles
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Holbery, James D. "Recycle polymer characterization and adhesion modeling /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/10586.
Повний текст джерела
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Ennahal, Ilyas. "Valorisation des sédiments de dragage dans des matrices polymères." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0015.
Повний текст джерелаАнотація:
En France, les volumes de sédiments de dragage générés chaque année pour la maintenance des ports et des voies navigables sont estimés à environ 50 millions de mètres cubes. La gestion de ces sédiments représente un enjeu économique, social et environnemental pour les gestionnaires. Aujourd’hui, l’une des solutions privilégiées est le développement de la gestion à terre de ces matériaux, qui consiste à les réutiliser comme matières premières secondaires en substitution partielle ou totale de matières nobles. De nombreux travaux de recherche ont été effectués sur la problématique de la valorisation des sédiments de dragage et de curage et de nouvelles filières sont actuellement toujours à l’étude (ciments, enrochements pour travaux maritimes et fluviaux, bétons cellulaires, granulats artificiels, etc.). Ce travail de thèse s’inscrit dans un contexte d’économie circulaire et vise à permettre le développement d’une gestion durable et responsable des ressources naturelles non renouvelables. Ceci à travers la réutilisation des sédiments de dragage dans la formulation de matériaux composites traités par des liants thermodurcissables ou thermoplastiques. Ainsi, après un travail de synthèse bibliographique sur les principales propriétés des sédiments de dragage, les méthodes de formulation des mortiers polymères et les modalités d’intégration des matériaux alternatifs dans ces matrices sont été décrites. Les expérimentations portent plus particulièrement sur la formulation de matériaux à partir de polymères thermodurcissables (résines de type Epoxy ou Polyester) et thermoplastiques (plastiques recyclés issus du tri des déchets). La validation des performances techniques des formulations optimisées pour chacun des traitements a été effectuée pour des usages en revêtements de sols ou en granulats légers dans des bétons hydrauliques. Enfin, la dernière partie de la thèse a été consacrée à l’étude de l’acceptabilité environnementale des nouveaux matériaux à travers la réalisation des essais de lixiviation dynamique sur monolithes. Les travaux menés ont permis de démontrer la faisabilité technique et environnementale de la valorisation des sédiments en tant que charge minérale dans des matrices polymères, avec des taux d’incorporation de sédiments significatifs pouvant atteindre jusqu’à 80 %. Ce qui confirme l’intérêt de cette typologie de traitement pour la valorisation des sédiments de dragageIn France, the volume of dredged sediments generated each year through maintenance of ports and waterways, is estimated at around 50M cubic meters. The management of these sediments represents an economic, social and environmental stake for the managers of the waterways. Today, one of the solution is the onshore management of these sediments, which consists on their reuse as secondary raw materials in partial or total substitution of natural materials for civil engineering applications such as sub-base road materials, embankments, concrete, bricks/tiles, and cement production. In this context this study was initiated in order to define a long-term value chain for dredging sediments for a sustainable and responsible management of natural resources. This through the valorization of dredged sediments in polymer matrix mortar formulations. Indeed, this research presents an innovative solution that preserves natural resources by promoting the use of local resources, such as dredged sediments. In order to achieve this objective, the study included several phases : the first part is devoted to the state of the art concerning dredged sediments, polymer mortars and the recovery of waste in polymer mortars. In the second part, we studied recovery of sediment in thermosetting matrix polymers (Epoxy-Polyester). In the third part we studied the possibilities of incorporating sediments in recycled thermoplastic matrix. The materials from this combination have been used as lightweight aggregates for mortar formulation. Finally, in the last part was devoted to environmental monitoring of new formulated materials. This is done through leaching tests carried out on crushed samples and monoliths, to ensure the environmental safety of these materials. The result obtained with the different formulations tested, show the technical and environmental feasibility of valorization of sediments as mineral filler in polymer mortars, with sediments incorporation rates range between 50 and 80%. Indeed, the use of a polymer matrix makes it possible to have better physico-mechanical and chemical results with cementitious matrix mortars
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Naït-Ali, Kako Linda. "Le PET recyclé en emballages alimentaires : approche expérimentale et modélisation." Montpellier 2, 2008. http://www.theses.fr/2008MON20023.
Повний текст джерела
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Mohammadzadeh, Maryam. "Characterization of recycled thermoplastic polymers." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19650.
Повний текст джерелаАнотація:
In this study thermal and mechanical properties and chemical structure of four differentpolymers (PE, PP, polyASA and PVC) were investigated to find out if the recycled polymershad the same properties and can be used in the same applications as the virgins or not.FT-IR was used for investigation of chemical structure. TGA, DSC and thermal stability wereused to compare the thermal properties. Tensile test also used to examine the mechanicalproperties.All the tests showed the recycling process is not done completely well. The differences inresults for virgins and recycled samples are the reasons which verified this claim.The results obtained from this study clarifying that the amount of stabilizer in the recycledpolymers were considerably less than the amount in virgins, means that the company had notadded enough stabilizer during the recycling process.
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El, Hajj Sleiman Ghinwa. "Aptitude à la mise en oeuvre de thermoplastiques recyclés et de biopolymère : analyse thermorhéologique de mélanges PP/PE." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4029/document.
Повний текст джерелаАнотація:
Le présent travail analyse l’effet de la présence de polluants sur le comportement thermo-rhéologique des thermoplastiques recyclés pendant sa mise en oeuvre. Nous avons fait une série d’expériences d’écoulement en utilisant des polymères pollués modèles (mélanges de PP/PE dont on connait la concentration relative). La pression et la température au sein d’écoulement ont été mesurées à l’aide d’un dispositif expérimental développé dans le laboratoire. Les résultats montrent un effet plus visible sur la pression de la présence de PP dilué dans le PE que dans le cas de PE dilué dans le PP. Ces résultats ont été expliqués par les différentes morphologies établies dans l’écoulement. Des modèles numériques ont été développés afin de confirmer les hypothèses faites sur ces morphologies. Pour étudier la sensibilité des grandeurs mesurables, pression et température, vis-à-vis de la fraction volumique de PE, on a développé un modèle analytique. Ce modèle appelé Einstein power law Epl décrit de façon fiable l’évolution de la viscosité du mélange de PP/PE en fonction de la concentration de PE diluée. Concernant le mélange de PP/PE avec une concentration diluée de PP, on a trouvé que le modèle de Lees est le meilleur pour décrire la viscosité de ce mélangeThis work deals with the effect of the presence of pollutants on the thermo-rheological behavior of recycled thermoplastics during process. We have realized multiple of experiments on models of recycled thermoplastics (mixtures of PP/PE knowing their relative concentrations). The pressure and the temperature within the flow were measured using a device that was developed in a previous work. The experimental results show an effect more visible on the measured pressure drops due to the dilute presence of PP in PE than that of the dilute presence of PE in PP. These observations can be explained by the different morphologies established in the flow. In order to confirm the hypotheses predicted on the morphologies of the mixtures, a finite element model was developed. To study the sensibility of the measureable parameters, pressure and temperature, with respect to the volume fraction of PE, we have developed an analytical model, Einstein power law, that describes the viscosity of the mixture of PP/PE with a dilute presence of PE. Concerning the mixture of PP/PE with a dilute presence of PP, we found that the Lees model is the best to describe the viscosity of such mixtures
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Basto, M. José Ricardo. "Mechanical characterization of aged recycled polymers and applications." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2649.
Повний текст джерелаАнотація:
Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains xxv, 217 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 163-164).
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Hugo, Annie-May. "Recycled polymer composites for structural applications." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/9520/.
Повний текст джерелаАнотація:
This thesis documents the development and testing of recycled, immiscible polymer blends for structural applications. The project was a Knowledge Transfer Partnership co-funded by Innovate UK and a Plastic Lumber manufacturer, who had a development contract with Network Rail. Network Rail contributed towards a permanent fatigue testing facility for full-size sleepers. Recycled plastic lumber converts lower grade, recyclate waste streams into products for decking, fencing, etc. The aim was to create formulations capable of carrying significant in-service, dynamic loads over a wide spectrum of outdoor temperatures and conditions with 50 years minimum service life for railway sleepers. Mixed polyethylene/polypropylene recyclates were tested in iterative laboratory trials reinforced with polystyrene, mineral fillers and glass fibre. Flexural properties and impact resistance amongst other tests aided formulation design for production trials. A synergistic reinforcing effect was found between glass fibre and mica within an immiscible recycled polymer blend. Polymer blends and fibre reinforced grades were manufactured by intrusion moulding into profiles up to 2800x250x130 mm. Profiles of four trial and two production grades were tested in flexure, compression and thermal expansion. Large statistical sample sizes were required due to waste stream batch-to-batch variability. Strength and modulus were found to change with manufacturing technique, profile size, profile orientation, test type, and test parameters. Strengths were good, though lower than predicted due to premature failure. The fracture process was found to initiate at inclusions, ductile crack growth continued to a critical size followed by brittle facture. Glass fibre significantly improved strength, modulus, maximum operating temperature and thermal expansion. In 2012, two major product approvals were attained after extensive qualification testing that included fatigue testing equivalent to 20 years in service. British Board of Agrément accredited a crib earth retaining wall system. Network Rail approved for track trial sleepers made from the glass fibre reinforced grade.
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Mitchell, Jonathan. "Recycled polymers reinforced with paper plastic laminates." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/58274.
Повний текст джерелаАнотація:
The aim of this research project was to develop new structural materials from the paper plastic laminate (PPL) waste stream. PPLs containing both paper fibre and plastic coatings are problematic for non-thermal recycling options. The current end of life disposal for PPL is primarily landfill. This work focuses on combining PPL wastes with recycled plastics to produce paper plastic composites (PPCs) that can be used as raw materials for a variety of applications. Plastic from a material recycling facility (MRF) consisting of polyolefins, together with polypropylene (PP) from Waste Electrical and Electronic Equipment (WEEE) wastes have been the main source of material for the composite matrix. The PPL wastes investigated include paper polyethylene coated disposable beverage cups and multi-layer Tetra Pak cartons. The majority of disposable cups are made from PPLs which consist of high quality cellulose fibre with a thin internal polyethylene coating. There are limited recycling options for PPLs and this has contributed to disposable cups becoming a high profile, problematic waste. In this work PPL wastes have been shredded to form PPL flakes and these have been used to reinforce polyolefins to form novel paper plastic composites (PPCs) based on the waste streams used. The PPL flakes and polyolefins were mixed, extruded, pelletised and injection moulded at temperatures to prevent degradation of the cellulose fibres. The PPLs were prepared by removing waste contaminants and granulated to the correct size to prevent bridging during extrusion. Processing temperatures were kept as low as possible to prevent fibre degradation. Extruded PPC blends were pelletised and injection moulded to form samples for testing. The effects of PPLs in PPCs on processing and properties have been investigated. This included studying the rheology of the extrusion mixes and the strength and stiffness of the PPCs. The effects of coupling agents such as maleated polyolefins and silane based compatibilisers to enhance adhesion between the PPL and the plastic have also been investigated. The level of PPL flake addition and the use of a maleated polyolefin coupling agent to enhance interfacial adhesion have been investigated. PPCs have been characterised and mechanically tested by a range of techniques including tensile testing, thermogravimetric analysis (TGA) and rheological experiments. Use of a coupling agent allows composites containing 40 wt.% of PPL flakes to increase the tensile strength of the recycled PP in this research by 50% to 30 MPa. The Young's modulus also increases from 1 to 2.5 GPa and the work to fracture increases by a factor of 5. The work presented here demonstrates that PPLs have potential to be beneficially reused as reinforcement in novel PPCs.
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Jordan, Michael Girdis. "Additive Manufacturing of Recycled Macadamia Nutshell – Polymer Composites." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/22707.
Повний текст джерелаАнотація:
This thesis examines the feasibility of using recycled macadamia nutshell to produce polymer composites via additive manufacturing. Macadamia nutshell powder is combined with the polymer Acrylonitrile Butadiene Styrene (ABS) and a binding agent to produce a filament to be used in Fused Deposition Modelling (FDM). The composites fabricated via this technique are subjected to a series of tests aimed at determining mechanical properties of the composites and their suitability in outdoor structural applications. Scanning Electron Microscopy (SEM) is used to characterise the microstructure of the composites and to determine the effects of the microstructure on the mechanical properties of these materials. The effects of particle size of the macadamia nutshell powder, fabrication parameters and composite composition are investigated to optimise the mechanical performance of the final component. Samples are also subjected to weathering tests to assess their suitability for use in outdoor structures. Macadamia nutshell – polymer composites were found to be a viable material for additive manufacturing. It was also found that macadamia nutshell – polymer composites showed higher specific strength compared to commercially available wood-plastic composite filaments. However, these newly developed composites did not perform as well as the commercially available filament as regards resistance to weathering.
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Liu, Kefan. "EFFECTS OF RECYCLED PET PARTICLE INCLUSION ON COMPRESSIVE STRENGTH OF CONCRETE." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1618948861158629.
Повний текст джерела
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Kegel, Mark Steven, and n/a. "Fibres from recycled post consumer PET/nylon 6 blends." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20070606.111448.
Повний текст джерелаАнотація:
The objective of this project was to develop blends based upon post consumer RPET and N6, and to evaluate the suitability of these blends to form fibres for the end use in carpet fibre.
In the work carried out it was found it is possible to spin RPET/N6 biconstituent fibres over a wide range of blend ratios. All the blends studied have diminished physical properties when compared to those of pure RPET and N6. The processability of these blends also deteriorated due to the large increases in normal forces which manifests in extrusion equipment as die swell that often results in melt fracture.
It has been shown that the morphology of the fibre controls the degree of decay in properties and die swell at the spinnerette. The blends that are rich in one phase, with the secondary phase distributed as elongated fibrils have shown better physical performance and improved processing compared to the blends 70/30 � 30/70, which have poorer properties and increased die swell due to there co-continuous morphology. In quiescent studies, the physical properties of the blends have had little deviation from those predicted using a rule of mixtures line. In and around the 50% RPET blend, die swell was observed to be extreme and this makes fibre spinning difficult. It was found that this was caused by a loss in viscosity in the blends and a general increase in normal forces in response to applied shear. The die swell phenomenon is a rheological characteristic of the blends, which was inevitably caused by internal capillary flow of one component in the other.
IR spectroscopy has shown that there is little to no in-situ compatibilisation occurring during simple melt processing. However, it was found that significant interfacial compatibilisation could be achieved through solid stating N6/RPET blends. The FTIR spectra for solid state blends in figure 4.51 has shown absorbency in the 3300 cm-1 region after all free N6 was removed. This indicates that in-situ compatibilisation has occurred between the phases in the solid stating process and it is a time dependent reaction.
The Burgers and Koltunov models can be used to predict the creep behaviour of the fibre blends studied. The Burgers model provides greater accuracy for longer-term exposure to stress.
From the thermal results, the solid stating process significantly affects the melting and crystallisation out of the melt and the ultimate level of crystallinity. The contribution of the copolymer in these changes appears to be small. The physical strength of the fibres made on the laboratory line was only marginally lower than those made on a factory line. The morphology of the mid-range blends is co-continuous and that of the N6 and RPET rich blends is dispersed droplet morphology.
Based on the finding, a N6 rich blends and in particular the 10% RPET blend is the most suitable for further commercial development as its processing, physical performance and post spinning processing closely resemble the pure N6 currently in use. It has provided performance and consistency throughout the processing and testing we have conducted.
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Adhikary, Kamal Babu. "Development of Wood Flour-Recycled Polymer Composite Panels As Building Materials." Thesis, University of Canterbury. Chemical and Process Engineering, 2008. http://hdl.handle.net/10092/1795.
Повний текст джерелаАнотація:
Wood plastic composites (WPCs) were made using matrices of recycled high-density polyethylene (rHDPE) and polypropylene (rPP) with sawdust (Pinus radiata) as filler. Corresponding WPCs were also made using virgin plastics (HDPE and PP) for comparison with the recycled plastic based composites. WPCs were made through melt compounding and hot-press moulding with varying formulations based on the plastic type (HDPE and PP), plastic form (recycled and virgin), wood flour content and addition of coupling agent. The dimensional stability and mechanical properties of WPCs were investigated. Durability performances of these WPCs were studied separately, by exposing to accelerated freeze-thaw (FT) cycles and ultraviolet (UV) radiation. The property degradation and colour changes of the weathered composites were also examined. Dimensional stability and flexural properties of WPCs were further investigated by incorporation of nanoclays in the composite formulation. To understand the changes in WPCs stability and durability performance, microstructure and thermal properties of the composites were examined. Two mathematical models were developed in this work, one model to simulate the moisture movement through the composites in long-term water immersion and the other model to predict the temperature profile in the composites during hot-press moulding.
Both rHDPE and rPP matrix based composites exhibited excellent dimensional stability and mechanical properties, which were comparable to those made from virgin plastics. Incorporation of maleated polypropylene (MAPP) coupling agent in composite formulation improved the stability and the mechanical properties. The incorporation of 3 wt. % MAPP coupling agent to WPCs showed an increase in tensile strength by 60% and 35 %, respectively, for the rHDPE based and rPP based composites with 50 wt. % wood flour. Scanning electron microscopy (SEM) images of the fractured surfaces of WPCs confirmed that the MAPP coupling improved the interfacial bonding between the plastic and the wood filler for both series of composites. Long-term water immersion tests showed that the water transport mechanism within the WPCs follows the kinetics of Fickian diffusion.
Dimensional stability and flexural properties of the WPC were degraded after 12 accelerated FT cycles as well as 2000 h of UV weathering for both recycled and virgin HDPE and PP based composites. However, the MAPP coupled composites had improved stability and flexural property degradation. The surface of the weathered composites experienced a colour change, which increased with the exposure time. The MAPP coupled composites exhibited less colour change as compared to non-coupled composites. Regarding the effect of the plastic type, the PP based composites experienced higher colour change than those based on HDPE. With weathering exposure, flexural strength and stiffness of the WPCs were decreased, but elongation at break was increased regardless of plastic type and wood flour content. MAPP coupled rPP and rHDPE based UV weathered WPCs lowered the degradation of stiffness by 50% and 75%, respectively compared to non-coupled WPCs. SEM images of the fractured surfaces of FT and UV weathered WPCs confirmed a decrease in the interfacial bonding between the wood flour and matrix. Thermal properties of weathered composites changed with weathering, but the extent of the changes depended on WPCs formulation and matrix type.
From the experimental studies on nanoclay-filled rHDPE composites, it is found that stability, flexural properties of WPCs could be improved with an appropriate combination of coupling agent, and nanoclay contents processed by melt blending. Incorporation of 1-5 wt. % nanoclay in the maleated polyethylene (MAPE) coupled wood plastic composite improved the dimensional stability and flexural properties. The thermal properties changed with the addition of nanoclay and MAPE in WPCs. In this work, a hot press-moulding model was proposed based on the one-dimensional transient heat conduction to predict the temperature profile of the WPCs during hot pressing cycle. The results from this work clearly show that rHDPE and rPP can be successfully used to produce stable and strong WPCs, which properties and performances are similar to or comparable to composites made of wood and virgin plastics. Therefore, WPCs based on recycled PP and HDPE matrix could have potential to use as construction materials.
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Tolga, Asli. "Nanocomposites Based On Recycled Poly(ethylene Terepthalate)." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606309/index.pdf.
Повний текст джерелаАнотація:
In this study, the effects of glycol type, organoclay type and concentration on the final properties of nanocomposites based on recycled poly(ethylene terephthalate) was investigated. For this purpose, first recycled PET was glycolysed and after that unsaturated polyester-montmorillonite nanocomposites were synthesized by using three different types of glycols (i.e. ethylene glycol (EG), propylene glycol (PG) and diethylene glycol (DEG)). As the first step, all the compositions were prepared by Cloisite 30B type of clay, and then for comparison of clay type, nanocomposites containing 1 wt. % of Cloisite 15A and Cloisite 25A type of clay were also synthesized. Morphological and mechanical analyses were performed for the characterization of the nanocomposites.
According to the results of XRD analysis, for all glycol types maximum intercalation was observed in Cloisite 30B containing samples. Exfoliated structures were obtained in the samples containing EG at 1 wt. % Cloisite 30B content and DEG at 3 wt. % Cloisite 30B content.
Mechanical tests showed that, for all properties, glycol type is the most effective experimental parameter. DEG based samples are the most flexible whereas PG based samples are the least flexible. EG and DEG based samples give maximum tensile strength and tensile modulus values at 1 wt. % clay loading. Samples prepared by DEG exhibited maxima in both flexural strength and modulus at 1 wt. % clay content. With respect to the organoclay type, Cloisite 30B containing samples gave the highest compatibility with the unsaturated polyester matrix as indicated by the tensile test results.
Organoclay type and content had no positive effect on the impact strength. Clay particles acted as stress concentrators and lowered the impact strength.
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Cengiz, Filiz. "Preparation And Characterization Of Recycled Polypropylene Based Nanocomposites." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609873/index.pdf.
Повний текст джерелаАнотація:
The aim of this study was to improve the mechanical properties of a recycled grade
polypropylene. Polymer blends and nanocomposites were prepared by melt
compounding method in a twin screw extruder. Cloisite®15A, Cloisite®
25A and Cloisite®
30B were used as organoclays, and ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) and maleic anhydride grafted polypropylene (PP-MAH) were used as compatibilizers. The effects of additive concentrations, types of organoclays and compatibilizers, processing conditions, and the compatibilizer to organoclay ratio on the morphology and mechanical, thermal and flow properties were investigated. Organoclay loading over 2 wt% prevented the intercalation mechanism and material properties, even in the presence of compatibilizer, as a consequence of large clay agglomerate formation. E-MA-GMA compatibilizer improved the intercalation ability of the polymer
however a substantial increase in mechanical properties was not obtained. PP-MAH is found to be a better compatibilizer. Processing conditions significantly affected both mechanical properties and morphology. When the processing temperature was decreased and screw speed was increased simultaneously, tensile and impact properties were improved owing to enhanced shear and dispersive forces. TEM analysis revealed that intercalated and delaminated structures were formed with the addition of PP-MAH compatibilizer. In addition to that, as the ratio of PP-MAH to organoclay was increased, more effective dispersion of organoclay was observed and hence resultant improvements in both tensile and impact properties were greater at compatibilizer to organoclay ratio of three. Cloisite®
15A exhibited the highest improvements in mechanical properties, although the degree of organoclay dispersion was better for Cloisite®
25A and particularly for Cloisite®
30B. Melt flow index values were lower compared to pure recycled polypropylene in the presence of organoclay and compatibilizers. DSC analysis indicated no significant change in the melting behavior of the matrix materials.
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Coulibaly, Mamadou. "Modélisation micromécanique et caractérisation expérimentale du comportement des matériaux hétérogènes élastoviscoplastiques : application à la valorisation des polymères recyclés." Thesis, Metz, 2008. http://www.theses.fr/2008METZ033S/document.
Повний текст джерелаАнотація:
Ce travail consiste à étudier le comportement mécanique des mélanges hétérogènes élastoviscoplastiques dans le but d une valorisation des matières plastiques recyclées. Par conséquent, notre étude porte sur l effet de la présence d impuretés ou de renforts sur le comportement mécanique des thermoplastiques de grande diffusion. Pour cela, une modélisation basée sur une approche micromécanique est menée sur ce type de matériaux. Toutefois, la complexité du comportement élastoviscoplastique qui est à l origine du caractère héréditaire du matériau et induit un couplage espace/temps, se traduit par la présence d interactions mécaniques différées que la transition d échelle doit s attacher à prendre en compte. Face à la lourdeur des approches de type héréditaire, on privilégie les approches à variables internes pour leur simplicité numérique. Dans ce cadre, ce travail a pour but de proposer une approche générale du problème de la transition d échelle. Il repose sur une nouvelle formulation intégrale du problème élémentaire d Eshelby. L étape d homogénéisation est ensuite effectuée suivant deux méthodes¡: l estimation de Mori-Tanaka et l approximation autocohérente. Les résultats obtenus sont présentés et comparés avec ceux d autres modèles et avec des résultats expérimentaux. Dans le cadre de la viscoélasticité linéaire, le modèle mis en œuvre dans cette étude conduit à la solution exacte se référant au modèle héréditaire de Rougier (transformée de Laplace-Carson). Dans domaine viscoélastique non-linéaire, et dans le but d une application au recyclage, une série d essais expérimentaux a été réalisée sur du polypropylène chargé de talcThis work relates to the modelling of mechanical behavior of elastoviscoplastic heterogeneous composites with the aim of an application to recycled polymers. Therefore, our study investigates the effect of the presence of impurities or strengthening agents on the mechanical behaviour of widely distributed thermoplastic polymers. In this way, a model based on a micromechanical approach is carried out on such materials. However, the complexity of elastoviscoplastic behaviour, that involves the hereditary type of material and induces a space/time coupling, is due to the presence of delayed mechanical interactions that scale transition should try to take into account. Considering the complexity of numerical implementation in hereditary approaches, internal variables approaches are privileged for their numerical simplicity. Within this framework, this development is intended to provide a general approach to the problem of scale transition. It relies on a new integral formulation of Eshelby inclusion problem. Then homogenization stage is carried out according to two methods : Mori-Tanaka estimate and self-consistent scheme. The results are presented and compared with those of other models and experimental results. The application to the case of linear viscoelasticity, the model used in this study led to the exact solution referring to Rougier hereditary model (Laplace-Carson Transform). In the non linear viscoelastic area, and with the aim of an application for recycling, a series of trials was conducted on polypropylene charged with talc
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Camacho, Walker. "Analytical techniques for quality assessment of separated and commingled recycled polymer fractions." Doctoral thesis, KTH, Polymer Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3326.
Повний текст джерелаАнотація:
Different methods for quality assessment of separated andcommingled plastics from household and electronic waste havebeen developed. Especial attention has been given tospectroscopic methods since they are non-destructive andrequire little or no sample preparation at all.
A wide variety of low molecular weight compounds have beenidentified in recycled polyethylene (HDPE) and polypropylenefrom hard packaging waste by gas chromatography- massspectroscopy (GC-MS) after microwave assisted extraction (MAE).Low molecular weight substances such as alcohols, esters,ketones and fragrance and flavour compounds were detected inthe recycled resins. The major category of compounds identifiedin the virgin resins is conformed by aliphatic hydrocarbonssuch as alkanes and alkenes. It was found that theconcentration of aromatic hydrocarbons without functionalgroups, e.g. ethylbenzene and xylenes in recycled HDPE wasapprox. 5 times higher and equal to 120 and 35 ppb,respectively.
The potential of near infrared (NIR) and Fourier transformRaman (FT-Raman) spectroscopy in combination with multivariateanalysis as a rapid, non-destructive and accurate analyticalmethod has been studied and the feasibility of these methodsfor at/in line characterisation of several properties ofrecyclates has also been explored.
NIR in diffuse reflectance mode has been successfully usedfor quantification of antioxidants in polyethylene, thestandard error of prediction is almost comparable to the errorof wet methods, i.e., extraction plus liquid chromatography.The error of prediction of this method is 35 ppm for Irganox1010 and 68 ppm for Irgafos 168. The inaccuracy in thequantification of Irgafos 168 is due to the fact that thisantioxidant degrades during polymer processing.
NIR and Mid-infrared (Mid-IR) worked well for fastdetermination of molecular weight and crystallinity of therecycled HDPE and acceptable errors of prediction, comparableto that of the reference methods, i.e. size exclusionchromatography (SEC) and differential scanning calorimetry(DSC) have been obtained.
The present thesis also shows that NIR and Raman are goodcandidates for in/on line compositional analysis of mixedpolymer fractions from recycled plastic waste. Diffusereflectance NIR allows a rapid and reliable measurement ofpellets and requires no previous sample preparation. Thecomposition of binary blends can be determined with highaccuracy. The PP content in the PP/HDPE blends was predictedwith a RMSEP equal to 0.46 %w in the 0-15 %wt region and theRMSEP for PP in the PP/ABS blends was 0.3 %wt.
The thermal and thermoxidative stability of recycled PP,HDPE and a 20/80 PP/HDPE blend subjected to multiple extrusionhave been studied by DSC, thermal analysis (TGA) andchemiluminiscence (CL). A decrease in Toxand OIT was observed after each extrusion step.The drop in OIT was sharper after the first two extrusions. TheOIT values produced by DSC and CL were in good agreement.However, CL provided more information about the oxidationprocess taking place in the blends.
The moisture content in recycled polyamide 6,6 was readilydetermined by NIR in transmission mode and it could bepredicted with a RMSEP = 0.05 %wt. The accuracy of the methodappeared to be as good as that of the more time consumingthermal methods such as TGA, DSC and loss on dry (LOD), whichwere used as reference methods. The influence of differentamounts of water on the viscoelastic properties of nylon hasbeen investigated.
Keywords:Recycling, HDPE, PP, blends, nylon 6,6, ABS,water content, MAE, GC-MS, NIR, FT-Raman, chemiluminiscence,low molecular weight compounds, antioxidant content,crystallinity, molecular weight, thermal stability,characterisation methods, analysis of polymers, blends.
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Behseta, Julie. "Synthetic and natural polymers recycled to make matter with new functionality and aesthetics." Thesis, Royal College of Art, 2013. http://researchonline.rca.ac.uk/1352/.
Повний текст джерелаАнотація:
This practice-led research will be accompanied by a dissertation which describes the research process and discusses the research questions and outcomes generated by the practice process. From an initial stage of laboratory and workshop experimentation with recycling High Density Polyethylene (HDPE) and General Purpose Polystyrene (GPPS), to a conclusion which brings experimental design practice to serve the needs of a specific user group, this research aims to show that the role of the designer in material-based research is multiple and complex. The significance of emotional experience is discovered to be of central importance to both material experimentation and the design for a specific user group. The initial context of sustainability becomes reframed through work with a community of residents, staff and relatives associated with a care home for the aged. From addressing the needs of a twenty- first century demographic challenge the designer finds complex meaning in the ecological, ethical and political agendas of sustainability. I employed a range of research methods in this project and conclude that qualitative research practice demands the integration of technical skills, sociological enquiry and an investigation into the ‘tacit knowledge’ of craftsmanship. I investigated the design potential of combining traditional craft and industrial technology to address the challenge of a future society and through this research into recycling plastics, polymers, textiles and other materials propose that material and meaning are closely interrelated. In my work the relationship between the visible traces of tactile sense and the presence of the hand is explored as a sign of ‘contact’ and transmission of emotion. The encasement and display of fibre, textile and personal objects in the plastic tiles is deployed as a medium of interior architecture with the potential to represent the meaning of the experience of end-of-life wellbeing. In this way the designer can make materials which encapsulate the sense of transition, departure, memory, presence and continuity for the old, their relatives and carers. Considering the principle of ‘Emotionally Durable Design’, this research finds new uses for old material.
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Jalilian, Mohammadali. "Impact of MXD6 on the Structure and Properties of Mechanically Recycled PET Blends." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1513354154142392.
Повний текст джерела
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Ventura, Cervellón Alejandra Marcela. "Sustainable polymer-tribology : Developing novel multiscale thermoplastic composites using recycled high-performance fibers." Thesis, Luleå tekniska universitet, Maskinelement, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86910.
Повний текст джерелаАнотація:
The transition to a Circular Economy scheme that enables a more efficient usage of the resources is one of the most pressing needs in our society. From the industrial perspective this has been translated into new design philosophies and the search for more efficient systems. Polymeric composites have played a key role in the development of lighter components with good mechanical and tribological properties. Specifically, the demand of Carbon Fiber Reinforced Polymers (CFRP) has had an increasing trend since 1970s-1980s, becoming one of the kind of composites with the highest demand in the market to supply industries such as aerospace, automotive, construction, renewable energies, among others. With the increasing demand of CFRP materials some of the main challenges that arise are their disposal, environmental impact and cost of production to maintain the required supply. The use of Carbon Fibers as a reinforcement for polymeric matrices has been widely documented over the last decades, however the characterization of recycled Carbon Fibers for tribological applications is still scarce. Therefore, this investigation is focused on the mechanical and tribological characterization under water lubricated conditions of Ultra High Molecular Weight Polyethylene (UHMWPE) composites reinforced with virgin and recycled Carbon Fibers and Graphene Oxide. The findings of this work provide an important panorama regarding the performance of recycled Carbon Fibers, showing that they can have a comparable performance in mechanical properties and tribological behavior. This enables the use of recycled Carbon Fibers without compromising performance while reducing the environmental impact and cost.
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Lund, Anna. "Material properties of recycled PET in beverage containers." Thesis, KTH, Fiber- och polymerteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296504.
Повний текст джерелаАнотація:
PET har under lång tid använts för flasktillverkning eftersom den är lätt, har goda barriäregenskaper och kan enkelt bearbetas industriellt. På senare tid har miljömedvetenheten ökat i samhället och därmed efterfrågan på återvunnet material, däribland PET-flaskor. Redan idag tillverkas flaskor med helt återvunnen PET. Återvunnen PET har dock kvalitetsproblem. Därför uppstår frågan hur materialegenskaperna hos 100% återvunna PET-flaskor påverkas av upprepade återvinningscykler. I den här rapporten undersöks hur den kemiska strukturen och egenskaperna förändras hos materialen allt eftersom fler återvinningscykler genomförs. Tre olika återvunna PET-material används för att ge ett bredare undersökningsunderlag och dessa tre material jämförs sedan sinsemellan samt med jungfrulig PET (icke-återvunnen PET) som referens. Egenskaperna analyseras med DSC för att ge information om termiska egenskaper, ATR-FTIR utförs för att detektera nedbrytning och förändring i den kemiska strukturen, dragprovning görs för att se hur återvinningen påverkar de mekaniska egenskaperna hos materialen och slutligen analyseras även den inneboende viskositeten hos de återvunna materialen. Examensarbetet visar på en markant minskning av inneboende viskositet med antalet återvinningscykler. Dessutom kan viss nedbrytning hos den kemiska strukturen ses via ATR-FTIR fastän inte så tydligt. Även en tendens till minskad kristallinitet med återvinning kan ses med DSC. En minskning i kristallinitet möjliggör produktion av mer transparenta flaskor, vilket ofta är eftertraktat. Emellertid får materialet försämrade barriäregenskaper. Dock krävs mer forskning för att kunna dra några slutsatser gällande materialegenskaper i industriell skala.PET has been used in bottle production for a long time since it is lightweight, easily processable and has good barrier properties. In recent years, the awareness of environmental issues has increased and thereby the demand for recycled materials, including PET bottles. Already today PET bottles with 100% recycled PET are produced. However, recycled PET bottles have quality problems. Thereby, the question arises how the material properties of 100% recycled PET bottles are affected when subjected to multiple recycling loops. In this report the changes in chemical structure and material properties of the materials are investigated as more recycling loops are performed. Three different recycled PET materials are used to give a broader base of information. These materials are compared to each other and to virgin PET (not recycled PET) as a reference. The materials are analysed with DSC to give information about the thermal properties, ATR-FTIR to detect changes in the chemical structure, tensile testing to see how the recycling affects the mechanical properties of the material and finally the intrinsic viscosity is analysed for the recycled materials. In this master thesis a clear decrease in intrinsic viscosity with increasing number of recycling loops can be observed. In addition, some degradation of the chemical structure can be seen through ATR-FTIR, although not very clearly. Also, a decrease in crystallinity with the number of recycling loops can be seen from DSC. A decrease in crystallinity enables production of more transparent bottles, which is often desired, although the material will have reduced barrier properties. However, more research is required to draw any conclusions regarding the material properties on an industrial scale.
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Alamri, Hatem Rashed. "Microstructural design and properties of high performance recycled cellulose fibre reinforced polymer eco-nanocomposites." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/765.
Повний текст джерелаАнотація:
In recent years, cellulose fibre-reinforced polymer composites have been gaining a great attention in several engineering applications due to their desirable properties, which include low density, low cost, renewability and recyclability as well as good mechanical properties. Moreover, cellulose fibres are environmentally friendly, non-toxic and renewable materials. Therefore, manufacturing industries especially packaging, building construction, automotive and furniture have been encouraged to use cellulose fibres in their applications instead of the more expansive and non-renewable synthetic fibres. However, one of the major drawbacks that has limited the use of cellulose fibres as reinforcement in polymer composites is their susceptibility to moisture absorption due to the hydrophilic nature of cellulose fibres. Moisture absorption can result in a reduction of mechanical properties and dimensional stability of composites. Several studies in plant fibre reinforced polymer composites have reported an enhancement in mechanical properties, fibre-matrix interfacial bonding and fibre resistance to moisture via various chemical or physical treatments. In this project, a novel approach has been used to enhance the resistance of cellulose fibre reinforced polymer composites to water absorption and to improve the mechanical properties by introducing a nano-filler that provides good resistance to water diffusion and enhances fibrematrix interfacial bonding for better mechanical properties.In this study, epoxy eco-nanocomposites reinforced with both recycled cellulose fibres (RCF) and different nano-fillers such as nanoclay platelets (Cloisite 30B), halloysite nanotubes (HNT) and silicon carbide nanoparticles (n-SiC) were synthesized. The influence of RCF/nano-filler dispersions on physical, thermal, mechanical and fracture properties was investigated in terms of water absorption, flexural strength, flexural modulus, impact strength, fracture toughness, impact toughness and thermal stability. The effect of water soaking on the mechanical properties of composites was also investigated. Different analytical methods such as wide angle X-ray scattering (WAXS), synchrotron radiation diffraction (SRD), transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to examine the nano and microstructures of these materials.First, multi layered recycled cellulose fibre (RCF) reinforced epoxy composites were fabricated with fibre loadings of 19, 28, 40, 46 and 52wt%. Results indicated that flexural strength, flexural modulus, facture toughness and impact strength increased as the fibre content increased. Water absorption and diffusion coefficient were found to increase with an increase in fibre content. Mechanical properties such as flexural strength, modulus and fracture toughness were found to decrease after water treatment due to the degradation of bonding at the fibre–matrix interfaces. The thermal stability of samples was determined using thermo-gravimetric analysis (TGA). Results indicated that the presence of cellulose fibres led to a reduction in the maximum decomposition temperature (Tmax) of epoxy. However, composites with cellulose fibre showed better thermal stability than neat epoxy at high temperature (≥ 600 oC). SEM observations showed a variety of toughness mechanisms such as crack bridging, fibre pullouts and fibre fracture and matrix cracking on the fracture surface of RCF/epoxy composites, which led to good fracture properties for samples reinforced by RCF layers.Second, epoxy-based nanocomposites reinforced with organo-clay platelets (Cloisite 30B), halloysite nanotubes (HNT) and nano-silicon carbide (n-SiC) were prepared by mixing the epoxy resin with three different filler loadings (1, 3 and 5 wt%) using a high speed mechanical mixer for 10 minutes with rotation speed of 1200 rpm. WAXS results showed that nanoclay platelets were intercalated by the epoxy resin. The d-space of the peak (001) of nanoclay increased from 1.85 to 3.4 nm after mixing with epoxy. TEM results showed a major intercalated structure with some exfoliated regions. Based on TEM results, the basal spacing of (001) varied from 2.65 to 7.98 nm. SRD results of HNT and n-SiC showed no change in the peak position after mixing with epoxy. TEM results of epoxy filled with nanoclay, HNT and n-SiC indicated that the dispersion of nanofiller was quite homogenous with some particle agglomerations that found to increase as filler content increased due to an increase in matrix viscosity. The addition of nano-fillers enhanced the mechanical properties of epoxy matrix.Maximum improvements in flexural strength, modulus and fracture toughness were achieved at 1 wt% of nano-filler loading, while the addition of 5 wt% of nano-filler displayed the maximum impact strength and toughness. The presence of nano-filler was found to have insignificant effect on the thermal stability of neat epoxy. Water absorption was found to decrease as the filler content increased. After six months of water treatment, there was a reduction in flexural strength and modulus, but an improvement in fracture toughness and impact strength. SEM results showed that nanocomposites had rougher fracture surfaces than that of neat epoxy. Several toughness mechanisms such as crack deflection, crack pinning, particle debonding, plastic void growth, plastic deformation and particle pullouts were observed.Finally, epoxy-based nanocomposites filled with nano-filler (i.e. nanoclay, HNT and n-SiC) were successfully used as a matrix for fabrication of multi-layers RCF/nano-filler reinforced epoxy econanocomposites. The presence of nano-fillers was found to have insignificant or modest effect on flexural strength, modulus and fracture toughness when compared to unfilled RCF/epoxy composites. Impact strength and impact toughness increased due to the presence of nano-fillers. The addition of nano-fillers increased the rate of the degradation by decreasing the maximum decomposition temperatures by about 8-9 oC compared to unfilled RCF/epoxy composites.However, the thermal stability of nano-filler filled RCF/epoxy eco-nanocomposites was found to increase at high temperature (≥ 500 oC). The presence of nano-fillers led to a significant decrease in maximum absorbed water compared to unfilled RCF/epoxy composites. Exposure to water for six months severely reduced the mechanical properties of wet composites when compared to dry composites. However, the addition of nano-fillers enhanced the mechanical properties of nanofiller reinforced RCF/epoxy eco-nanocomposites compared to unfilled RCF/epoxy composites in wet condition. SEM results showed that water absorption led to degradation in cellulose fibres and weakening of the bonding at fibres-matrix interfaces. Enhanced barrier and mechanical properties of nanocomposites were more pronounced for composites filled with n-SiC as compared to those filled with nanoclay platelets and halloysite nanotubes.The success in this project indicated that this approach of ‘designing for recycling’ or ‘ecodesign’ to develop environmentally friendly composite materials is achievable. Moreover, this project may provide a great momentum for a ‘cradle to grave’ approach in the eco-design of fully ‘green’ or biodegradable and environmentally friendly composite materials through the use of nanoclay and recycled cellulose fibres as reinforcement for bio-resins.
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Lam, Thuy Quynh. "Qualification mécanique de composites à base de polymères recyclés et de fibres végétales : caractérisation des mécanismes de rupture par imagerie numérique." Poitiers, 2004. http://www.theses.fr/2004POIT2339.
Повний текст джерелаАнотація:
Cette étude, cofinancée par l’ADEME et la Région Poitou-Charentes, propose d’explorer la voie du recyclage mécanique des déchets plastiques en les utilisant comme matrice dans des composites à charges d’origine végétale. Les matériaux étudiés sont le polypropylène (PP), le polyéthylène haute densité (PEhd), et des fibres d’épicéa. Les polymères ont été recyclés jusqu’à 20 fois, en utilisant le matériel de la plate-forme technologique de Valagro (Poitiers). Nous avons ajouté dans ces polymères des fibres d’épicéa à différents taux massiques. L’analyse des matériaux obtenus s’est faite suivant deux axes : étude de l’évolution microstructurale et caractérisation du comportement mécanique. Les résultats ont permis de mettre en évidence la présence d’une transition ductile-fragile dans le PP au cours du recyclage, et l’apparition progressive de la phase cristalline dans le PP lorsque le taux de renfort augmente dans les composites. Le couplage des mesures des champs de déformations par corrélation d’images numériques en pointe de fissure avec les simulations par éléments finis a permis de caractériser l’évolution de paramètres mécaniques des matériaux étudiésIn this study, jointly supported by ADEME and Poitou-Charentes region, it is proposed to exploit a mechanical recycling method for plastic wastes by using them as matrices in natural composites. The studied materials are polypropylene (PP), high density polyethylene (PEhd) and spruce fibres. The polymers supplied by Valagro platform (Poitiers) have been recycled up to 20 times. Then, spruce fibres have been added to these polymers with different fibre weight fractions. The analysis of the so-obtained materials has been carried out along two main lines: the study of the microstructural evolution on one hand and the characterization of the mechanical behaviour on the other. The results have displayed the appearance of a ductile-brittle transition in PP during the mechanical recycling and a progressive appearance of crystalline phase with increasing fibre weight fraction. A coupling between strain maps obtained by the digital image correlation method at a crack tip and the simulation by the finite element method has enabled the evolution of some mechanical parameters of the studied materials to be characterized
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Rattanapan, Suwat. "Preparation and Properties of Bio-Based Polyurethane Foam Prepared from Modified Natural Rubber and Poly(ε-caprolactone)". Thesis, Le Mans, 2016. http://www.theses.fr/2016LEMA1036/document.
Повний текст джерелаАнотація:
L’objectif de ces travaux de recherche était de synthétiser de mousses polyuréthane (PUF) bio-basées à partir d’oligomères hydroxytéléchéliques issus du caoutchouc naturel (HTNR) ou à partir de poudrettes de pneus usagés (HTWT) et du diol de la polycaprolactone (PCL) comme segments soft. Les paramètres étudiés ont été le type de polyol et le rapport molaire entre HTNR/PCL et HTWT/PCL. La masse molaire de HTNR, HTWT et PCL étaient respectivement 1,800, 1400 et 2000 g/mol. L’effet du rapport molaire HTNR/PCL et HTWT/PCL (1/0, 1/0/5/, 1/1, et 0.5/1) sur la vitesse de formation des mousses et sur les propriétés chimiques et physiques a été étudié. Les structures chimiques de HTNR, HTWT et PUF ont été confirmées par FTIR et 1H-RMN. Le diol de la PCL était le plus réactif donc augmentant le contenu de PCL-diol la vitesse de formation des mousses a augmenté. La densité des mousses a changé légèrement avec le rapport molaire cependant la résistance à la traction reste dans la même gamme. Le diamètre moyen des cellules a augmenté en fonction du contenu de PCL-diol et la tendance inverse a été observée pour l’allongement à la rupture et la résistance à la compression. L’observation au microscope électronique à balayage (MEB) a montré que les mousses basées sur les HTNR étaient alvéolées et fermées. La biodégradabilité a été évaluée selon le test de Sturm. Polyéthylène à baisse densité et benzoate de sodium ont été utilisés respectivement comme témoins négatif et positif. Les mousses ont montré une période d’induction de 33 jours dans lequel le pourcentage de dégradation était ~ 7-10%. La biodégradation de PUF contenant seulement HTNR a été 8.4% après 28 jours et 31.89% après 60 jours ; les PUF contenants 1/0.5 HTNR/PCL ont montré un pourcentage supérieure : 11.31% après 28 jours et 45.6% après 60 jours. Le rapport molaire HTWT/PCL a influencé beaucoup la vitesse de formation des mousses et leur morphologie. Cellules fermées de forme polyédrique ont été observé par microscopie électronique à balayage. Les résultats de l’analyse thermogravimétrique ont montré que l’addition du diol de la PCL a augmenté la température de dégradation. Il a été observé qu’une basse vitesse de réaction génère des mousses à haute densité, petit diamètre de cellule et haute distribution des diamètres. La biodégradation des PUF contenant seulement HTWT a été 31.2% après 28 jours et 51.3% après 60 jours, tandis que les PUF contenant 1/0.5 HTWT/PCL ont montré une dégradation plus élevée : 39.1% après 28 jours et 64.3% après 60 jours. La vitesse de formation des mousses basées sur les HTWT était supérieure à celle des mousses basées sur les HTNR. Toutes les mousses basées sur les HTWT ont une densité supérieure et une taille de cellule inférieure à celles basées sur HTNR. La structure des cellules des mousses basées sur les HTNR ou HTWT était différente cependant toutes les mousses ont montré des cellules quasi complètement fermées. Les mousses basées sur les HTWT ont montré des propriétés thermiques et de biodégradation meilleures par rapport aux mousses basées sur les HTNRThe aim of this research was to prepare a bio-based polyurethane foam (PUF) containing hydroxyl telechelic oligomers from natural rubber (HTNR) and waste tire crumbs (HTWT) and polycaprolactone diol (PCL) as soft segments. The studied parameters included type of polyols and molar ratio between HTNR/PCL and HTWT/PCL. The molecular weight of HTNR and HTWT derived from 1H-NMR spectra were 1,800 and 1,400 g/mol, respectively. The molecular weight of PCL diol was 2000 g/mol. The effect of HTNR/PCL and HTWT/PCL molar ratio (1/0, 1/0.5, 1/1 and 0.5/1) on the foam formation rate and physical and chemical properties of the resulting PUF was investigated. The chemical structure of HTNR, HTWT and PUF were confirmed by FTIR and 1H-NMR. PCL diol provided faster reaction, thus higher PCL diol content showed higher foam formation rate. The foam density slightly changed with the molar ratio whereas the specific tensile strength of all samples was in the same range. The average diameter of cell increased with increasing contents of PCL diol. The addition of PCL diol resulted in reduced elongation at break and compressive strength. The cellular structure observed by SEM micrographs of HTNR based foams showed an almost closed cell. The biodegradability was assessed according to a modified Sturm test. Low density polyethylene and sodium benzoate were used as a negative and positive control sample, respectively. PUF samples showed an induction time of 33 days in which the percentage of biodegradation was 7-11%. The biodegradation of PUF containing only HTNR was 8.4% and 31.89% at 28 days and 60 days of testing respectively whereas the PUF containing 1/0.5 HTNR/PCL (by mole) showed a higher biodegradation: 11.31% and 45.6% at 28 days and 60 days of testing respectively. The molar ratio of HTWT/PCL strongly affected the kinetic rate of foam formation and foam morphology. According to SEM micrographs, polyhedral closed cells were observed. The addition of the PCL diol increased the thermal degradation temperature of the PUF based on TGA results. A low kinetic rate provided PUF with a high density, small cell size and a broad cell size distribution. The biodegradation of PUF containing only HTWT was 31.2% and 51.3% at 28 days and 60 days of testing respectively whereas the PUF containing 1/0.5 HTWT/PCL diols (by mole) showed a higher biodegradation: 39.1% and 64.3% at 28 days and 60 days of testing respectively. The foam formation rate of HTWT based PUF was higher than the one of HTNR based PUF. All HTWT based PUF have a higher density than HTNR based PUF. The HTWT based PUF had an inferior cell size in comparison to HTNR based PUF. The cellular structure of HTNR based and HTWT based PUF were different, but all PUFs showed almost closed cells. The HTWT based PUF had a higher thermal degradation temperature and biodegradation properties than foams from HTNR
วัตถุประสงค์ของงานวิจัยนี้ เพื่อทำการเตรียมโฟมพอลิยูรีเทนชีวภาพ (PUF) จากยางธรรมชาติดัดแปรที่มีหมู่ปลายไฮดรอกซิล (HTNR) ยางคลัมบ์ดัดแปรที่มีหมู่ปลาย ไฮดรอกซิล (HTWT) และพอลิคาโปรแลคโทน (PCL) ศึกษาผลของชนิดพอลิออล และสัดส่วนโดยโมลระหว่าง HTNR/PCL และ HTWT/PCL ที่สัดส่วน 1/0, 1/0.5, 1/1 และ 0.5/1 โดยโมล นํ้าหนักโมเลกุลของ HTNR, HTWT และ PCL ที่ใช้สำหรับงานวิจัยนี้ คำนวณจาก 1H-NMR คือ 1,800, 1,400 และ 2,000 g/mol ตามลำดับ ลักษณะโครงสร้างทางเคมีของ HTNR, HTWT และPUF สามารถวิเคราะห์และยืนยันด้วยเทคนิค FTIR และ 1H-NMR รวมถึงทำการวัดอัตราการก่อโฟม (Foam formation rate) ทดสอบสมบัติทางกายภาพ ทางเคมี และสมบัติการย่อยสลายทางชีวภาพ พบว่าในกรณีของโฟมพอลิยูรีเทนจาก HTNR/PCL เมื่อใช้ PCL ในปริมาณที่มากขึ้นจะส่งผลให้อัตราการก่อโฟมเร็วขึ้น และขนาดของเซลโฟมมีขนาดใหญ่ขึ้นด้วย ในขณะที่ค่าความหนาแน่น และความต้านทานต่อแรงดึงจำเพาะมีการเปลี่ยนแปลงเล็กน้อย การเติม PCL ในส่วนผสมของโฟมยังส่งผลให้ความสามารถในการยืด ณ จุดขาด และความทนทานต่อการกดมีค่าลดลง การคืนตัวหลังการกดของโฟม PUF2 (สัดส่วนระหว่าง HTNR/PCL = 1/0.5) จะให้ค่าตํ่าที่สุดคือ 40% ลักษณะของโฟมที่ได้จากการทดลองนี้โดยส่วนใหญ่จะเป็นแบบเซลปิด ความสามารถในการย่อยสลายทางชีวภาพของโฟม ทดสอบโดยใช้วิธี Sturm Test มี LDPE เป็นตัวเปรียบเทียบเชิงลบ และใช้ Sodium benzoate เป็นตัวเปรียบเทียบเชิงบวก พบว่าโฟมเริ่มมีการย่อยสายเกิดขึ้นอย่างเห็นได้ชัดที่เวลา 33 วัน มีเปอร์เซ็นต์การย่อยสลายในช่วง 7-11 เปอร์เซ็นต์ เปอร์เซ็นต์การย่อยสลายของโฟมจาก HTNR (PUF1) อยู่ที่ระดับ 8.4 และ 31.89 เปอร์เซ็นต์ และเปอร์เซ็นต์การย่อยสลายของโฟมจาก HTNR/PCL (1/0.5) อยู่ที่ระดับ 11.31 และ 45.6 เปอร์เซ็นต์ ที่เวลาในการทดสอบ 28 และ 60 วัน ตามลำดับ กรณีของโฟมพอลิยูรีเทนจาก HTWT/PCL เมื่อใช้ PCL ในปริมาณที่มากขึ้นจะส่งผลให้ค่าความหนาแน่นสูงขึ้น ขนาดของเซลโฟมลดลงมีการกระจายของเซลในวงกว้างไม่สมํ่าเสมอ เปอร์เซ็นต์การย่อยสลายทางชีวภาพของโฟมจาก HTWT (PUF5) อยู่ที่ระดับ 31.2 และ 51.3 เปอร์เซ็นต์ และเปอร์เซ็นต์การย่อยสลายของโฟมจาก HTWT/PCL (1/0.5) อยู่ที่ระดับ 39.1 และ 64.3 เปอร์เซ็นต์ ที่เวลาในการทดสอบ 28 และ 60 วัน ตามลำดับ เมื่อทำการเปรียบเทียบโฟมที่ได้จากการเตรียมโดยใช้พอลิออลหลักเป็น HTNR และ HTWT พบว่าโฟมจากพอลิออลหลัก HTWT ให้อัตราการก่อตัวของโฟมเร็วกว่า ขนาดของเซลโฟมเล็กกว่า ความหนาแน่น ความต้านทานต่อความร้อน และเปอร์เซ็นต์การย่อยสลายทางชีวภาพสูงกว่า เมื่อเทียบกับโฟมจากพอลิออลหลัก HTNR
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Gröning, Mikael. "Solid-Phase Microextraction in Polymer Analysis - Extraction of Volatiles from Virgin and Recycled Polyamide 6.6." Doctoral thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-60.
Повний текст джерелаАнотація:
The extraction and quantitative analysis of low molar mass compounds in polymers is an analytical challenge. It is also important from a practical point of view because the low molar mass compounds in time will migrate from the polymers into the surrounding environment. It is especially important to gain knowledge about the migrating compounds in applications such as medical implants, packaging materials and car interiors. The main aim of this thesis was to develop headspace solid phase microextraction (HS-SPME) methods to meet this challenge. In addition, the work aimed to show the applicability of the methods developed in quality control of polymers, degradation studies and assessment of polymer durability.
Factors influencing the extraction of low molar mass compounds from polyamide 6.6 were studied. Particular attention was paid to the matrix effects and to the establishment of headspace equilibrium of 2-cyclopentyl-cyclopentanone in solid polyamide. Hydrogen bonding and adsorption of analyte to the polar matrix was observed and found to cause exceedingly slow establishment of equilibrium. The adsorption could be eliminated by the addition of water, which replaced 2-cyclopentyl-cyclopentanone at the adsorption sites of the polyamide and made it possible to measure the 2-cyclopentyl-cyclopentanone content in polyamide 6.6 using multiple headspace solid-phase microextraction (MHS-SPME).
A correlation between the emitted amount of 2-cyclopentyl-cyclopentanone and the amount 2-cyclopentyl-cyclopentanone in the material was found. The correlation was valid also under non-equilibrium conditions, which allows rapid assessment of the 2-cyclopentyl-cyclopentanone content in polyamide 6.6 using headspace sampling.
20 different low molar mass compounds were identified in virgin and recycled polyamide 6.6. The compounds could be classified into four groups: cyclic imides, pyridines, chain fragments and cyclopentanones. The structures of the degradation products imply that the thermo-oxidative degradation starts at the N-vicinal methyl group. Larger amounts of degradation products at lower degree of degradation were formed in recycled than in virgin polyamide 6.6. Thus, processing increases the susceptibility of polyamide 6.6 to thermal oxidation. The total amount of cyclopentanones was reduced upon processing and oxidation. Cyclopentanones are thus not thermo-oxidation products of polyamide 6.6. N-pentyl-succinimide showed the most significant increase due to oxidation and processing. The formation of N-pentyl-succinimide was in correlation with the simultaneous changes in tensile strength. The largest increase in N-pentyl-succinimide coincided with the largest drop in tensile strength.
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Gröning, Mikael. "Solid-phase microextraction in polymer analysis : extraction of volatiles from virgin and recycled polyamide 6.6 /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-60.
Повний текст джерела
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Pandey, Ganesh. "Feasibility Study of Water Based / Polymer Modified EICP for Soil Improvement Involving Recycled Glass Aggregate." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron153115070027817.
Повний текст джерела
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BrandÃo, Andre Schramm. "Study of manhole degradation of recycled PE rotomolded used in network sewer." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11624.
Повний текст джерелаАнотація:
Conformity MENDONÃA [10], the investments in sanitation are four times more effective than health. There are currently answering sewage deficit in Brazil, reaching 52.9 percent of the population. The infrastructure of sewage systems of large cities has a huge variety of materials, ranging from concrete to composite materials. Disorders caused by premature failure of materials, applied in sewage systems cause environmental pollution, depreciate image utility/company and even accidents. The manholes represent 15.5 percent of the costs of implementing the sewage systems. This study aims to assess the effects of the degradation of manholes in polyethylene (PE) recycled. The accelerated degradation test simulates the etching with sulfuric acid, present in sewage systems (pH 1.1) of the test specimens for mechanical tensile and impact. The PE was produced by the rotational molding process, from virgin and recycled raw material for comparative purposes. Before the attack the materials were characterized by thermal analysis tests thermogravimetry (TG) and differential scanning colorimetric (DSC), X-ray diffraction, melt index, ash and loads. Data from the thermography images compared with assays term analysis revealed that machining by computer numerical control (CNC) did not change the mechanical properties of specimens for tensile and impact tests . Analyses term perspective and stereopsis revealed flaws in the rotational molding process (bubbles, sink marks and surface irregularity). The crystallinity of recycled PE was greater than virgin PE, this property being obtained by DSC and X-ray. The resistance of the recycled PE fracture was higher, ratified by the crystallinity and moisture present (Technical TG). The melt flow index and mechanical tests revealed that the virgin PE is more ductile than recycled. After the attack the specimens increased their residual mass being 3 times more recycled PE. Destructive of the specimens after chemical attack, trials there were no significant changes in the mechanical properties because of the high standard deviation data, arising from the failure of the material rotational molding process.Segundo MendonÃa [10], os investimentos realizados em saneamento bÃsico sÃo quatro vezes mais eficazes que na saÃde. Atualmente, hà dÃficit de atendimento de esgotamento sanitÃrio no Brasil, atingindo 52,9% da populaÃÃo. A infraestrutura de redes coletoras de esgoto (RCEs) de grandes cidades possui uma imensa diversidade de materiais, que vÃo desde o concreto atà os materiais compÃsitos. Transtornos causados pela falha prematura dos materiais, aplicados nas redes coletoras de esgoto causam poluiÃÃo ambiental, desgaste da imagem da concessionÃria/empresa e atà acidentes. Os poÃos de visita (PVs) representam 15,5% dos custos para implantaÃÃo de RCEs. Este trabalho tem como objetivo a avaliaÃÃo dos efeitos da degradaÃÃo dos PVs em polietileno (PE) reciclado. O ensaio de degradaÃÃo acelerada simula o ataque quÃmico com Ãcido sulfÃrico, presente nas RCEs (pH de 1,1) dos corpos de prova para ensaios mecÃnicos de traÃÃo e impacto. O PE foi produzido pelo processo de rotomoldagem, de matÃria prima virgem e reciclada, para fins comparativos. Antes do ataque os materiais foram caracterizados por ensaios de anÃlises tÃrmicas de termogravimetria (TG) e colorimetria diferencial de varredura (DSC); difraÃÃo de raios X (DRX); Ãndice de fluidez; teor de cinzas e cargas. Os dados das imagens termogrÃficas comparativamente com os ensaios de termoanÃlises revelaram que a usinagem por meio do controle numÃrico computadorizado (CNC) nÃo alterou as propriedades mecÃnicas dos corpos para os ensaios traÃÃo e impacto. As termoanÃlises e a estereoscopia Ãtica revelaram as falhas do processo de rotomoldagem (bolhas, rechupes e irregularidade na superfÃcie). O grau de cristalinidade do PE reciclado foi maior do que o PE virgem, sendo esta propriedade obtida pelas tÃcnicas de DSC e Raios X. A resistÃncia a fratura do PE reciclado foi superior, ratificada pelo grau de cristalinidade e umidade presente (tÃcnica TG). O Ãndice de fluidez, juntamente com ensaios mecÃnicos, revelou que o PE virgem à mais dÃctil que o reciclado. ApÃs o ataque, os corpos de prova aumentaram sua massa residual, sendo trÃs vezes mais que o PE reciclado. Os ensaios destrutivos dos corpos de prova apÃs o ataque quÃmico, nÃo houve alteraÃÃes significativas das propriedades mecÃnicas, visto o alto desvio padrÃo dos dados, oriundo das falhas do material provenientes do processo de rotomoldagem.
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Moallemi, Pour Sadaf. "Investigation of compressive bond behavior of steel and fiber reinforced polymer bars embedded in recycled aggregate concrete." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57927.
Повний текст джерелаАнотація:
Over the past several years, one of the important issues concerning the construction
industry has been sustainable development. Therefore, usage of sustainable building materials and the reuse and recycling of previously used building materials have been considered in many areas. Recycling of construction and demolition (C&D) wastes could prevent their costly disposal which is hazardous to the environment. Utilization of demolished concrete as a coarse aggregate, often termed as recycled coarse aggregate (RCA) for producing industry quality concrete, could lead to a solution to the environmental conservation and pave the way towards sustainability by reducing the consumption of natural aggregate. During the development of this new generation product, it is essential to investigate the structural properties of reinforced RCA concrete to promote its application, in the construction industry. Besides, fiber reinforced
polymer (FRP) composite rebars have been widely used in construction instead of steel rebars. Their non-corrosive nature and high tensile strength are the main reason of this replacement. Performance of reinforced concrete members at serviceability and ultimate limit states is controlled by the bond between reinforcement and concrete which is a critical design parameter. This research aims to evaluate RCA application in structural concrete and investigate the bond properties between reinforcing steel/FRP bars and RCA concrete. Bond performance of 35 MPa RCA concrete was assessed through an experimental plan. Five RCA replacement percentages and different diameters of reinforcing bars were used. Effects of embedment length and concrete cover to bar diameter ratio on the bond strength were moreover considered. It was observed that under constant mix proportions, an increase in the bar size and the embedment length to bar diameter ratio leads to a reduction in the bond strength due to growth of voids trapped between the bar surface and concrete. Like regular concrete, larger concrete cover helps improving the bond behavior. On average, acceptable bond strengths were observed in RCA samples which were close to control results. In addition, smaller bar diameter and larger concrete cover can improve bond behavior of specimens embedded with FRPs in comparison with steel ones.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Kumaraswamy, Pillai Subha. "Functionalized polymer building blocks for high performance bioplastic production using novel green catalysts and recycled vegetable oil." Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25339.
Повний текст джерелаАнотація:
Cette thèse de doctorat a pour objectif le développement d'un catalyseur hétérogène très actif et sélectif pour la conversion d'huiles végétales usées en monomères pour le développement de bioplastiques via la réaction d’auto-métathèse. Le méthyltrioxorhénium supporté sur l’alumine mésoporeuse modifiée avec ZnCl2 s’est avéré un catalyseur actif pour l'auto-métathèse de l'oléate de méthyle, une molécule modèle pour les triglycérides des huiles. Les produits obtenus à partir de la métathèse de l'oléate de méthyle comprennent, un diester, le 1,18-octadecenedioate et un alcène, 9-octadécène, qui peut être utilisé comme monomère pour la synthèse des polymères lorsqu'il est associé à d'autres molécules. Les conditions de réaction telles que la température, le temps de réaction et le promoteur utilisé ont été optimisées pour obtenir un rendement élevé en produits de la métathèse de l'oléate de méthyle. Le catalyseur 3% MTO/ZnCl2-Al2O3-meso avec un rapport Al/Zn de 8 à la température de réaction de 45°C pendant 60 min a été trouvé actif pour la métathèse de l'oléate de méthyle. Il a été également observé que les autres halogénures métalliques et des chlorures n'ont pas favorisé la réaction comme le ZnCl2. L'amélioration de l'activité du catalyseur par l’addition de ZnCl2 à Al2O3-méso a été expliquée en raison de la nature acide de Lewis améliorée par le ZnCl2. Les études cinétiques ont montré que le catalyseur a été très actif permettant une conversion supérieure à 80% en 30 min de réaction entre 25°C et 60°C. L'activité catalytique à la température ambiante était aussi encourageante pour l'auto métathèse de l'oléate de méthyle. Les conditions opératoires optimisées pour la métathèse de l'oléate de méthyle ont par la suite été étendues à l'application de triglycérides, en l’occurrence la trioléïne qui est abondante dans l’huile de tournesol et autres huiles végétales. Le catalyseur a été trouvé actif avec la formation de l'alcène 9-octadécène ainsi que des dimères et des trimères de la trioléine. Le catalyseur à base de MTO a été actif pour la formation des produits de métathèse désirés et le produit non désiré de métathèse comme le polymère réticulé formé par la réaction à catalyse homogène a été évité.Les résultats prometteurs pour la métathèse des trioléïnes prouvent que le catalyseur 3% MTO/ZnCl2-Al2O3-meso peut être utilisé pour la métathèse des huiles végétales comme l'huile de tournesol riche en acide oléique qui contient la trioléïne comme sa principale composante.This doctoral thesis aims at the development of highly active and selective heterogeneous catalyst for conversion of used vegetable oils into monomers for bioplastic development using self-metathesis reaction. The catalyst based on methyltrioxorhenium supported on mesoporous alumina modified with ZnCl2 was found to be an active catalyst for self-metathesis of methyl oleate, a model molecule for triglycerides of oils with high turnover number. The products obtained from the metathesis of methyl oleate include the diester, 1,18-Octadecenedioate and an alkene, 9-Octadecene which can be used as monomer for polymer synthesis when reacted with other molecules. The reaction conditions such as temperature, reaction time, the promoter used were optimized to obtain high yield of products from the metathesis of methyl oleate. The catalyst 3% MTO/ZnCl2-Al2O3-meso with Al/Zn ratio of 8 at reaction temperature of 45°C for 60 min was found to be active for metathesis of methyl oleate. It was also found that the other halides and metal chlorides did not promote the reaction similar to ZnCl2. The enhancement of activity by addition of ZnCl2 to Al2O3-meso was found to be due to the Lewis acidic nature enhanced by addition of ZnCl2. The kinetic studies showed that the catalyst was highly active resulting in conversion> 80% within 30 min of reaction between 25°C to 60°C. The catalytic activity at room temperature was also promising proving it to be a very efficient catalyst for self metathesis of methyl oleate. The conditions optimized for methyl oleate metathesis was extended for the application of triolein, the abundant triglyceride present in the high oleic sunflower oil and other vegetable oils. The catalyst was found to be active with formation of the alkene 9-Octadecene and the dimers and trimers of triolein as desired metathesis products. The MTO based catalyst was active in forming the desired metathesis product and the undesired product namely the cross-linked polymer formed with the homogeneously catalyzed reaction was avoided. The promising results for the metathesis of triolein prove that the catalyst 3% MTO/ZnCl2-Al2O3-meso can be used for the metathesis of vegetable oils such as high-oleic sunflower oil which contains triolein as its major component.
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MELIS, GIANLUCA. "Life cycle assessment to support the design of a new road manufacturing process with recycled materials." Doctoral thesis, Politecnico di Torino, 2022. https://hdl.handle.net/11583/2973987.
Повний текст джерела
34
Xie, Wa. "Surface Topography and Aesthetics of Recycled Cross-Linked Polyethylene Wire and Cable Coatings." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc799512/.
Повний текст джерелаАнотація:
Our research focuses on re-using a waste a material, cross-linked polyethylene abbreviated XLPE, which is a widely used coating for wires. XLPE is strong and has excellent thermal properties due to its chemical structure - what leads to the significance of recycling this valuable polymer. Properties of XLPE include good resistance to heat, resistance to chemical corrosion, and high impact strength. A wire is usually composed of a metal core conductor and polymeric coating layers. One creates a new coating, including little pieces of recycled XLPE in the lower layer adjacent to the wire, and virgin XLPE only in the upper layer. Industries are often wasting materials which might be useful. Mostly, some returned or excess products could be recycled to create a new type of product or enable the original use. This method helps cleaning the waste, lowers the costs, and enhances the income of the manufacturing company. With the changing of the thickness of the outer layer, the roughness changes significantly. Moreover, different processing methods result in surfaces that look differently.
35
Keyfoglu, Ali Emrah. "Effects Of Chain Extension And Branching On The Properties Of Recycled Poly(ethylene Terephthalate)-organoclay Nanocomposites." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605020/index.pdf.
Повний текст джерелаАнотація:
In this study, the effects of chain extension and branching on the properties of nanocomposites produced from recycled poly(ethylene terephthalate) and organically modified clay were investigated. As the chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. The nanocomposites were prepared by twin-screw extrusion, followed by injection molding. Recycled poly(ethylene terephthalate), was mixed with 2, 3 and 4 weight % of organically modified montmorillonite. During the second extrusion step, 0.5, 0.75 or 1 weight % of MA or PMDA was added to the products of the first extrusion. As the second extrusion step is reactive extrusion, the anhydrides were added at three different screw speeds of 75, 150, 350 rpm, in order to observe the change of properties with the screw speed.
XRD analysis showed that, the interlayer spacing of Cloisite 25A expanded from 19.21 Ǻ
to about 28-34 &
#506
after processing with polymer indicating an intercalated structure. PMDA, MA and organoclay content as well as the screw speed did not have a recognizable effect on interlayer distance. In the first extrusion step, nanocomposites containing 3% organoclay content gave significant increase in Young&rsquo
s modulus and decrease in elongation to break values indicating good interfacial adhesion. After the addition of chain extenders, it was observed that both MA and PMDA gave rise to improved mechanical properties of the nanocomposite owing to the branching and chain extending effects that increase the molecular weight. However, PMDA gave better mechanical properties at lower content which makes it a more effective chain extender. DSC analysis showed that MA was more effective in increasing the glass transition temperature and melting temperature in comparison to PMDA.
36
Klusková, Jana. "Využití polymerů do konstrukcí vozovek pozemních komunikací." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-410117.
Повний текст джерелаАнотація:
The diploma thesis deals with the use of recycled polymers in asphalt mixtures. In the theoretical part of the thesis there is discussed the global issue of plastic waste including the experience of foreign countries, where this technology has already been introducted and used. The practical part is devoted to the proposal of using recycled plastic in asphalt mixture, description of used laboratory tests and the evaluating the effect of low-density polyethylen (LDPE) on the asphalt mixture type AC. There were performed tensile strenght tests, water resistant tests and stiffness modulus tests in the laboratory (E). The output of this work is an evaluation of measured values, processing of results and their interpretation depending on the possible use of this technology in Czech republic.
37
Bob, Mustafa M. "Enhanced removal of natural organic matter during lime-soda softening." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1047486107.
Повний текст джерелаАнотація:
Thesis (Ph. D)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xxii, 119 p.: ill. Includes abstract and vita. Advisor: Harold W. Walker, Civil Engineering Program. Includes bibliographical references (p. 115-119).
38
Taddei, Lorenzo, F. Ugolini, G. P. Bonino, G. Giacomelli, C. Franceschi, M. Bertoldini, R. Sole, and V. Beghetto. "Biopolymers for a more sustainable leather -154." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34185.
Повний текст джерелаАнотація:
Content:
A novel class of bio-based polymers have been developed within the LIFE BIOPOL European project aiming to replace traditional re-tanning and fat-liquoring products reducing environmental impacts and increasing the safety of leather.
The purpose of the project is to enhance the recovery and reuse of different bio-derived by-products from leather and agro-industrial sector to produce eco-friendly and renewable bio-polymers with high re-tanning and fat-liquoring characteristics.
The LIFE BIOPOL project aims to make bio-based polymers in order to reduce the following parameters in re-tanning phase:
- 20-30% COD,
- 50-60% of inorganic salts (Sulphates and Chlorides),
- 90% of Cr (III) salts,
- 20% of water used in the leather process.
Other important goals of the project are:
- reduction 70-90% of hazardous and environmental polluting substances normally found in conventional chemicals,
- reactivity enhancement of 30-40% of the new biopolymers compared to the current leather
- application technology,
- reduction of 70-80% of the Product Environmental Footprint of the new biopolymers related to the state of the art.
The vegetal biomasses and the tanned hides by-products were pretreated in order to obtain suitable building blocks for the production of bio-based polymers. Several protocols involving polymerization were
used in order to achieve the synthesis of the biopolymers, which have been carried out at lab scale.
Macromolecular characterization of the biopolymers was performed in order to rationalize the synthetic strategy and practical application of the products giving important parameters such as molecular weight
and chemical composition of the new biopolymers.
Performances of new bio-based polymers have been inspected and compared with traditional chemicals through application on different types of leather. The benefits of the new products within leather making process were evaluated through chemical analyses of re-tanning and fat-liquoring effluents.
The upgrade of the developed chemistry will be performed within a new devised prototype plant specifically designed and built-up for producing the bio-based polymers at industrial scale
Take-Away:
Production of leather making biopolymers from biomasses and industrial by-products through Life Cycle Designed Processes
39
Kosuri, Madhava Rao. "Polymeric membranes for super critical carbon dioxide (scCO2) separations." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28242.
Повний текст джерелаАнотація:
Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: William J. Koros; Committee Member: Amyn Teja; Committee Member: Carson Meredith; Committee Member: Sankar Nair; Committee Member: Wallace W. Carr.
40
Junior, Luiz Carlos GonÃalves Pennafort. "Application of the mechanical of the damage in the analysis of the behavior of polymer composites recycled reinforced by coconut fiber." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14005.
Повний текст джерелаАнотація:
Com os crescentes movimentos ecolÃgicos em todo o mundo, onde o objetivo principal visa conscientizar e estimular a populaÃÃo mundial a poupar os recursos naturais, aliado a necessidade de se desviar os resÃduos aterrados (sanitÃrios ou industriais), de forma a reduzir os problemas ambientais e de saÃde pÃblica, decorrentes da disposiÃÃo inadequada de resÃduos sÃlidos, surgem os incentivos a reciclagem de materiais, bem como o desenvolvimento de materiais biodegradÃveis. Diante deste contexto, os materiais compÃsitos reforÃados com fibras naturais ganham destaque no meio cientÃfico. No entanto, seu uso ainda à tido com desconfianÃa, devido ao pouco ou nenhum conhecimento desses promissores materiais. Perante essa problemÃtica, surgiu a proposta deste trabalho de carÃter investigativo, em que foi pesquisado e desenvolvido um compÃsito totalmente reciclado, de matriz termoplÃstica (PVC reciclado) reforÃado, com fibras obtidas da casca de cocos verdes descartados. Para esse objetivo foram utilizadas diversas ferramentas de caracterizaÃÃo fÃsica, quÃmica, tÃrmica e mecÃnica, sendo os valores dos campos de deformaÃÃo obtidos pela CorrelaÃÃo de Imagem Digital (CID), comparando a imagem do corpo nÃo deformado com imagens do corpo deformado. E finalmente, avaliou-se os processos de danificaÃÃo do compÃsito, atravÃs da caracterizaÃÃo experimental da evoluÃÃo do dano isotrÃpico pelos mÃtodosda variaÃÃo do MÃdulo de Elasticidade efetivo (ensaio de traÃÃo com carga e descarga) e pelo Ãndice de Tsai-Wu com os parÃmetros constitutivos da funÃÃo tangente hiperbÃlica, onde os valores encontrados, em ambos os mÃtodos, mantiveram-se dentro da faixa esperada para compÃsitos, 0,20 â 0,50.With increasing the ecological movements around the world, whose the main objective aims to raise awareness and encourage the world's population to save natural resources, coupled with the need to divert grounded waste (sanitary or industrial) in order to reduce environmental problems and public health, arising f rom the improper disposal of solid waste, emerge incentives for recy cling, and the development of biodegradable materials. Given this context, the composites reinforced with natural fibers began to be highlighted in the scientific community. However, its utilization is still seen with suspicion due to little or no knowledge of these pr omising materials. Faced with this problem, arose the proposal of this investigative character work, in with it was researched and devel oped a fully recycled composite, of thermoplastic matrix (recycl ed PVC) reinforced with fibers obtained from the bark of green coconut s discarded. For this objective were used various tools of physical, chemical, thermal and mechanical characterization, whose amounts of d eformation fields were obtained by Digital Image Correlation (DIC), c omparing the image of the body not deformed with images of the deforme d body. Finally, we assessed the processes of damage of the composite, through experimental characterization of the evolution of t he isotropic damage by the methods of varying the effective elastic mod ulus (tensile test with loading and unloading) and by Tsai-Wu index wi th the parameters constitutive of hyperbolic tangent function, where the values found, in both methods, were within the expected range for composite, from 0.20 to 0.50.
41
Fernandes, Marcelo Vicente Forestieri. "Produção de composto polimérico a partir de polímeros reciclados: resíduos de espuma flexível de poliuretano, e polipropileno reciclado." Universidade Presbiteriana Mackenzie, 2013. http://tede.mackenzie.br/jspui/handle/tede/1337.
Повний текст джерелаАнотація:
Made available in DSpace on 2016-03-15T19:36:40Z (GMT). No. of bitstreams: 1
Marcelo Vicente Forestieri Fernandes.pdf: 3433992 bytes, checksum: 0bc6007ed63ec4c257f1064d9e03e6cc (MD5)
Previous issue date: 2013-12-06This paper discusses a study to prepare a composite of recycled polypropylene with recycled polyurethane, from manufacturing flexible foam waste, used for making mattresses and upholstery. Searches about using these materials on office chairs design, recycling and about aplying these materials on product design. Are done mechanical, thermal and rheologic tests of pure polypropylene, recycled polypropylene and the new compound with addition of recycled polyurethane in proportions 10%, 20%, 40% and 50% to characterize and compare materials. The results presents PU influences on both compounds, but with higher influence on recycled polypropylene base. PU filler increased composite viscosity related to original polymers and decreased plastic deformation before break. Besides not to contain a detailed economic viability study, this work showed technical possibility to develop a polymer composite using PU from flexible foam waste.
O presente trabalho abordou um estudo de elaboração de um composto de polipropileno reciclado com reciclado de poliuretano, proveniente de retalhos de fabricação de espuma flexível, utilizada para a confecção de colchões e estofados. Foram realizadas pesquisas sobre a utilização desses materiais na confecção de cadeiras de escritório, a reciclagem de materiais e a utilização desses materiais no design de produtos. Foram realizados ensaios mecânicos, térmicos e reológicos, de polipropileno virgem, de polipropileno reciclado, e do composto de polipropileno reciclado com poliuretano e polipropileno virgem com poliuretano, nas proporções 10% e 20%, 40% e 50% a fim de caracterizar e comparar os materiais compostos obtidos. Os resultados indicaram a influência da carga de PU em ambos compostos, porém com maior influência nos de matriz de polipropileno reciclado. A carga aumentou a viscosidade dos compostos em relação às matrizes originais e também diminuíram a deformação plástica antes da ruptura. Apesar de não contar com um estudo detalhado de viabilidade econômica, o estudo aponta a possibilidade técnica de desenvolver um composto polimérico de polipropileno com carga de PU proveniente de retalhos de espuma flexível.
42
Pyreňová, Eliška. "Studium vlastností polymery modifikovaných malt využívající pucolánově aktivní materiály." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240307.
Повний текст джерелаАнотація:
This diploma thesis is focused on the study of the properties of polymer-modified cementitious mortars which using pozzolanic active materials based on amorphous silica. Explores the possibilities of using the recycled glass as a partial replacement of cement in PMM. Properties of mortars are reviewed in mineralogical and technological point of view. For specification of the results were used the analysis RTG, DTA and REM.
43
Ballista, Luiz Paulo Zuppani. "Avaliação de algumas propriedades de concretos estruturais com agregados graúdos reciclados modificados com látex estireno-butadieno." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-13112015-142759/.
Повний текст джерелаАнотація:
Esta pesquisa objetiva avaliar o emprego de agregados graúdos reciclados (produzidos a partir do entulho de construção e demolição) e o emprego do látex estireno-butadieno (polímero sintético) nas propriedades de concretos estruturais de média resistência. Todos os estudos são conduzidos comparando-se as propriedades de concretos com agregados naturais sem adição de látex, e de concretos com agregados graúdos reciclados com e sem adição de látex. Na primeira fase da pesquisa, são avaliadas propriedades físicas e mecânicas destes concretos. São analisados três traços (com diferentes consumos de cimento) modificados com quatro percentagens de látex e submetidos a quatro formas de cura. Os resultados da primeira fase formam a base para a segunda fase da pesquisa, na qual apenas um dos traços contendo uma determinada porcentagem de látex e sob uma única forma de cura é submetido a ensaios em célula de corrosão acelerada e aderência aço-concreto. Como resultado principal, tem-se que o emprego conjunto de agregados graúdos reciclados e látex estireno-butadieno fornece concretos com resistência mecânica equivalente aos concretos contendo agregados naturais e com desempenho em ambientes agressivos e aderência aço-concreto também semelhantes. Conclui-se, portanto, pela viabilidade do emprego destes concretos como concreto estrutural armado no que tange às propriedades avaliadas.This research aims at evaluating the use of coarse recycled aggregates (produced from construction and demolition debris) and the use of styrene-butadiene latex (synthetic polymer) in the concrete constitution of medium resistance concrete structures. All studies are carried out comparing the concrete properties with natural aggregates without latex, and concrete with coarse recycled aggregates with or without latex. In the first stage of the research, physical and mechanical properties of these concretes are evaluated (with different cement contents) modified with four percent of latex and submitted to four cure condition. The results of the first stage produce the base for the second stage of the research, where only one of the features containing a determinate percentage of latex and under a sole form of cure condition it is submitted to tests in accelerated corrosive cell and steel-concrete adherence. As a main result, it is believed that the joint usage of coarse recycled aggregates and styrene-butadiene latex provides mechanical resistant concrete equivalent to concrete containing natural aggregates with a similar performance in aggressive environments and with steel-concrete adherence. Due to the its employment feasibility, one can conclude that this concrete is structurally armed in as far as its properties were evaluated.
44
Dalfré, Gláucia Maria. "Cruzetas de polímeros reciclados: caracterização dos materiais, análise numérica e ensaios de modelos reduzidos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-13042007-100416/.
Повний текст джерелаАнотація:
Atualmente, a madeira ainda é o material mais usado nas cruzetas das redes aéreas de distribuição de energia elétrica no Brasil, o que vem causando problemas às companhias distribuidoras de energia elétrica quanto a: (i) degradação devida a defeitos e a ataques de fungos e de insetos, (ii) aumento dos custos operacionais, para a substituição das peças danificadas e (iii) problemas ambientais, uma vez que a matéria-prima está se tornando escassa e apresenta restrições ambientais. Nesse sentido, estudos vêm sendo realizados visando a substituição da madeira por outros materiais, tais como aço, concreto e materiais poliméricos reforçados com fibras. Embora os materiais termoplásticos com função estrutural sejam de uso bastante recente, quando comparados com madeira, concreto ou metais, vários fatores contribuem para sua utilização (e.g., o alto consumo energético na produção do aço e do cimento e a abundância de material plástico com custo competitivo). Diante disso, este trabalho tem por objetivo contribuir para o desenvolvimento de uma cruzeta de polímero reciclado, de modo que ela seja comercialmente competitiva e que apresente vantagens quando comparada com as demais cruzetas existentes no mercado, tais como peso reduzido, facilidade de instalação e possibilidade de retorno de parte do capital investido, uma vez que, quando danificadas, o material pode ser novamente reciclado. Para tanto, realizou-se uma análise das propriedades geométricas de possíveis seções transversais para as cruzetas. Uma vez definidas as seções mais adequadas, foram feitos modelos reduzidos de cruzetas poliméricas e ensaios experimentais, cujos resultados foram validados por análise numérica feita com o programa ANSYS. Constatou-se que os modelos numéricos desenvolvidos representaram de forma satisfatória o comportamento verificado nos ensaios e comprovaram a viabilidade de empregar os polímeros reciclados em cruzetas e em outros elementos estruturais. Entretanto, com era de se esperar, será necessário melhorar algumas de suas características, tais como a resistência e a rigidez.Nowadays, wood is still the most used material in crossarms of aerial power distribution lines in Brazil. However, it has caused problems to power utilities concerning (i) degradation due to defects and attacks of fungi and insects, (II) higher operational costs to replace damaged pieces and (III) environmental problems, as the raw material has become scarce and presented environmental restrictions. In this sense, studies have been conducted aiming to replace wood by other materials, such as steel, concrete and polymeric materials reinforced with short fibers. Although thermoplastic materials with structural function have a recent use, when compared to wood, concrete or metals, several factors contribute to their application (e.g., high energetic consumption in the production of steel and cement and the abundance of plastic material with competitive cost). Therefore, this work aims contribute to the development of a recycled polymer crossarm, to be commercially competitive, with advantages over the ones existing in the market, such as lower weight, easiness of installation and possibility of recovering part of the invested capital, when damaged, the material can be recycled again. An analysis of the geometric properties of possible transversal sections for the crossarms was conducted. After defining the most adequate sections, reduced models of polymeric crossarms and experimental tests were made. The results were validated by numerical analysis performed by ANSYS. The numerical models developed satisfactorily represented the behavior verified in the tests, proving the viability of using the recycled polymers in crossarms and other structural elements. However, as expected, some of their characteristics, such as resistance and stiffness, must be improved.
45
Jankech, Filip. "Elastomerní plniva jako potencální surovina pro betony a malty." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-295668.
Повний текст джерелаАнотація:
To attain a sustainable development in the field of building materials, it is necessary to consider environmental, economic, and social aspects of the industrial production. This thesis addresses the first two aspects. Both theoretical and practical research were implemented in order to study the possibility to replace the commonly used RDPs, that are being used in the dry-mix mortar industry as a primary additive, with the industrially processed elastomer waste materials, such as recycled tire rubber. The review of the scientific literature processed within the theoretical research discloses the state of the art in the field of polymer modification of the mortar products and the effect of the commonly used modifiers and elastomer fillers on the performance of mortar and concrete products. The experimental research was implemented to study the possibility of the replacement of the RDPs for the elastomer fillers. The performance of fresh and hardened mortar containing various amounts of elastomer particles was studied. The results indicate, that the partial replacement could be feasible without worsening the performance of the product.
46
Candian, Lívia Matheus. "Estudo do polietileno de alta densidade reciclado para uso em elementos estruturais." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-10042008-093848/.
Повний текст джерелаАнотація:
O alto consumo de energia para a produção de metais e de cimento, a pressão em relação à utilização de madeira tropical e a abundância de material plástico vêm contribuindo para o desenvolvimento de pesquisas e a aplicação dos termoplásticos na construção civil, em elementos estruturais que, em sua grande maioria, são constituídos de madeira, de aço e de concreto. O progresso dos materiais poliméricos pode ser comprovado pelos diversos produtos que estão sendo projetados, principalmente na Europa e nos Estados Unidos, como passarelas, dormentes, marinas, etc. Foi escolhido o polietileno de alta densidade (PEAD) reciclado, por ser um dos materiais poliméricos rígidos mais disponíveis para reciclagem. Nesse contexto, o objetivo deste trabalho foi a caracterização do PEAD reciclado. Foi determinada a composição do material polimérico (PEAD) reciclado obtido no mercado, por meio dos ensaios termoanalíticos: calorimetria exploratória diferencial e análise termogravimétrica. Os resultados mostraram que o material fornecido pela empresa de reciclagem é isento dos contaminantes comumente encontrados nos materiais reciclados e apresenta um grau de pureza bastante significativo. A determinação das propriedades mecânicas, por meio dos ensaios de tração, de compressão, de flexão e de impacto Izod, finaliza o estudo do material analisado. Nesses ensaios, a resistência obtida foi próxima dos valores encontrados na literatura, para o PEAD virgem, e pouco inferior à do concreto e à da madeira. Entretanto, a rigidez do PEAD reciclado foi bem menor que a dos materiais de construção tradicionais, sendo essa sua maior deficiência. Concluiu-se que o PEAD reciclado pode ser aplicado em elementos estruturais, desde que sejam estudadas possíveis formas de controlar sua deformabilidade, como a incorporação de nervuras, a utilização de blendas poliméricas e adição de cargas minerais e de fibras de elevado módulo de elasticidade e resistência.The use of thermoplastics in civil engineering has been increasing considerably in the last decades. The latter is due to large amount of plastic material and high cost on a production of metals and cement for reinforced concrete, besides the lack of wood. This could be proved by the development of new thermoplastics products, especially in Europe and United States, like bridges, railway sleepers, posts, etc. Recycled high density polyethylene (HDPE) was chosen due to the fact that it is one of the most rigid recycled polymers available on the recycling industry. In this study, recycled polymer has been characterized in order to determinate the recycled material composition available in the market. The characterization of recycled HDPE samples was made by thermo gravimetric analysis and differential scanning calorimetry. Consequently, mechanical properties were determinated by tensile test, compression test, flexural test and impact Izod. The results of thermal analysis showed that the recycled material is exempt from possible contaminants and has a significant pureness degree. Under tension, compression, bending and impact conditions, the strength was around the pure polymer and little smaller of the concrete and wood. In contrast, the stiffness was much lower in comparison to traditional materials, their worst characteristic. These problems could be overcome through the study of polymeric blends, adding high modulus and strength fibers and charges and adding ribs. Then the recycled polymer could be applied as a structural element.
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Szadeczki, Marika. "Ozonation de pâte thermomécanique : ozonations de mélanges de pâtes thermomécaniques et chimiques : application aux fibres recyclées." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0192.
Повний текст джерелаАнотація:
Pour des raisons ecologiques et economiques, le recyclage des papiers et cartons s'intensifie. Cependant, l'accroissement de la masse de vieux papiers recuperes entraine une diminution de la qualite des fibres a recycler. Plusieurs solutions sont examinees pour ameliorer la qualite des fibres recyclees dont l'ozonation. Celle-ci conduit a des resultats encourageants a l'echelle du laboratoire, mais ces resultats sont parfois contradictoires, en raison de l'heterogeneite des pates de vieux papiers. Par consequent, une recherche plus fondamentale a ete initiee pour examiner l'effet de l'ozone sur des melanges de pates mecaniques et chimiques qui modelisent les differentes sortes de pates recyclees. Au prealable, l'action de l'ozone sur une pate mecanique a ete approfondie. L'ozonation de pate mecanique entraine une degradation des caracteristiques optiques et une amelioration des caracteristiques mecaniques. Le principal phenomene responsable de ces modifications serait la delignification qui conduit a une structure de feuille plus compacte, la creation de groupements carboxyle n'intervenant pas de maniere significative. Dans un melange de pate chimique et de pate mecanique ozonee, les modifications apportees par l'ozone ne se repercutent sur les proprietes du melange que s'il contient plus de 10% de pate mecanique. Elles sont d'autant plus significatives que les qualites des deux pates composant le melange sont proches. Applique a un melange 10% de pate mecanique, 90% de pate chimique, l'ozone ameliore la blancheur et, si le melange contient des charges, les caracteristiques mecaniques. Si le melange contient 35% de pate mecanique, l'ozone augmente les caracteristiques mecaniques. Le blancheur et l'indice de dechirement sont conserves pour les melanges avec charges. Ces resultats, obtenus sur des melanges faits en laboratoire, se retrouvent sur les pates recyclees industrielles, de meme composition fibreuse, uniquement si elles sont acidifiees avant leur caracterisation et leur ozonation. De plus, cette derniere serait handicapee par la presence de contaminants, susceptibles de reagir avec l'ozone. Les connaissances acquises devraient permettre une utilisation plus judicieuse et mieux ciblee de l'ozone dans le traitement des vieux papiers.
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Gianelli, Élvia Cristina. "Utilização de polipropileno reciclado na fabricação de envoltório de rodas para indústria automotiva." Universidade de Taubaté, 2010. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=277.
Повний текст джерелаАнотація:
Gradativamente, os materiais poliméricos passaram a ter uma importância maior para as indústrias do setor automobilístico. O aumento do uso de materiais poliméricos está em desencontro com as questões ambientais, quando leva em consideração o destino final a ser dado para as peças produzidas em materiais poliméricos. Este trabalho tem por objetivo apresentar resultados de ensaios utilizando misturas de polipropileno reciclado com polipropileno virgem, aplicados à produção de peças de envoltórios de rodas automotivas. Foram utilizados dois fornecedores para o polipropileno virgem, quatro fornecedores para o polipropileno reciclado e dois fornecedores de masterbatch. Concluiu-se que o uso de polipropileno reciclado para a produção de envoltório de rodas é possível sem prejuízo ao desempenho do produto final. As amostras contendo o material PPR4 do (polipropileno reciclado 4) do fornecedor de polipropileno reciclado 4, com misturas até 50%, apresentaram desempenho funcional que satisfazem às exigências da indústria automotivas, montagem sem restrições no dispositivo dimensional, sem quebras no ensaio de resistência ao impacto por queda de esfera. O material PPR4 quando misturado a um masterbatch com modificador de impacto e antioxidante, MB1, do fornecedor de masterbatch 1, apresentou valores médios
acima de 18kJ/m para o ensaio de resistência ao impacto Charpy, e para o ensaio de resistência a termooxidação suportou mais que 200h. Resultados que evidenciam a possibilidade do uso de polipropileno reciclado na produção de envoltórios de roda. Portanto, este estudo visa fornecer uma contribuição para o aumento do uso de material reciclado dentro da indústria automotiva.Gradually, the polymeric materials have been given greater importance for the automotive industry. The increasing use of polymeric materials is in disagreement with environmental issues, while taking into account the final destination to be given for parts produced in polymeric materials. This paper aims to present results of tests using mixtures of recycled polypropylene with virgin polypropylene, used to produce parts of wraps of automotive wheels. We used two suppliers for the virgin polypropylene, four suppliers for recycled polypropylene and two suppliers of masterbatch. It is concluded that the use of recycled polypropylene to produce wheel wrap is possible without detriment to the final product performance. The samples containing the material PPR4 (recycled polypropylene 4), of the supplier for recycled polypropylene 4, with mixtures of up to 50% showed functional performance that meets the requirements of the automotive industry, assembly unrestricted dimensional device, without breaks in the trial of impact resistance by falling ball. The material PPR4 when mixed with a masterbatch with an impact modifier and antioxidant, MB1, supplier of masterbatch 1, showed values above 18kJ/m for the testing of Charpy impact strength, and to test for resistance to thermo-oxidation endured more than 200h. Results show that the possibility of using recycled polypropylene in the production of wheel wraps. Therefore, this study aims to provide a contribution to the increased use of recycled material in the automotive industry.
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Benešová, Anna. "Optimalizace složení dřevoplastových kompozitů s ohledem na jejich využití ve stavebnictví." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-390253.
Повний текст джерелаАнотація:
Wood-polymer composite is a relatively new type of material that combines shattered wood mass and a thermoplastic polymer. This material is utilized especially as an alternative to hard wood in the area of non-bearing exterior elements, as it reaches better properties in terms of the basic durability and low maintenance. Raw material composition and processing of the composite enable to provide a significant modification with further matters leading to an improvement of the end-product properties. Research and development in this field focuses predominantly on the utilization of such modifying additives that either enhance the resistance to weathering or are of the recycled nature, as a significant part of the raw material mixture comprises the constituent obtained from non-renewable resources. The aim of the thesis is the evaluation of the influence of the wood-polymer composite modification separately at two levels. First of them is the modification to matrix by using a recycled polymer, the second one comprises the modification of the wood flour with a secondary spherical filler. Both types of modified composites have been assessed in terms pf the prime characteristics and the resistance to adverse ambient.
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Ek, Emmelie. "Återvunnet vatten : använda renat avloppsvatten i processen." Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-22095.
Повний текст джерелаАнотація:
Fältstudien gjordes för att utreda om det var möjligt att använda renat, filtrerat avloppsvatten för polymerberedning och i längden även som övrigt processvatten på Ellinge reningsverk. Testerna utfördes i fullskala med både vatten från mellansedimenteringen och slutsedimenteringen. Genom omfattande provtagningar och analysering av resultaten visade det sig vara en fungerande metod utan negativ påverkan på polymerlösningen och slamavvattningen. Det krävs dock mer arbete och ytterligare reningssteg såsom desinficering för att implementera det renade avloppsvattnet på hela vattensystemet.The field study was done to investigate whether it was possible to use purified, filtered wastewater for polymer preparation and in the long run also as other process water at Ellinge treatment plant. The tests was performed in full scale with both water from the intermediate sedimentation and the final sedimentation. Through extensive sampling and analysis of results, it proved to be a working method without a negative impact on the polymer solution and sludge dewatering. However, more work and addiotional purification steps such as disinfection are required to implement the treated wastewater on the entire water system