Dissertations / Theses on the topic 'Polypropylene Composites Reinforced'
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Biyana, Nobuhle Yvonne. "Studies on flax/polypropylene-reinforced composites for automotive applications." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/d1021150.
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The use of natural fibers as reinforcement in thermoplastics presents an interesting alternative for the production of low cost and ecologically friendly composites. One of the advantages of using natural fibres is their low specific weight, resulting in higher specific strength and stiffness when compared to glass reinforced composites. Natural fibres also present safer handling and working conditions. They are non-abrasive to mixing and can contribute to significant cost reduction. This work is divided into two phases: Phase 1 deals with developing nonwoven mats composites from flax/polypropylene (PP) and evaluating their properties. Flax/polypropylene fibres (at different weight ratios) were processed by needle-punching technique in order to form nonwoven mats. The mats were compression-molded at a temperature of 180oC to form composite materials. The mechanical, thermal and viscoelastic properties of the composites were analyzed. Composites (untreated and silane-treated) were also subjected to varying conditions of temperature and humidity and the tensile properties of the conditioned and unconditioned composites were investigated. The mechanical properties (tensile, flexural and impact) of flax/PP composites were found to increase and reach maximum values at 30 per cent fibre loading and then decrease at higher fibre content. Thermal studies revealed that the composites were stable up to 320oC and samples containing 40 per cent flax fibres were found to exhibit greater thermal stability than neat PP. The dynamic mechanical analyses of the composites showed that the incorporation of flax in the composites resulted in an increase of the storage modulus with a maximum value exhibited by composite containing 40 per cent fibre loading. Composites containing chemically modified fibres exhibited low tensile modulus after conditioning. Phase 2 is based on the investigation of the effect of nano-calcium carbonate (CaCO3) on the properties of two types of polymer matrices: recycled PP and virgin PP. In this case, composites were prepared by melt-mixing and injection molding. The mechanical and thermal properties of the composites were characterized. The tensile modulus of the nano-CaCO3 filled PP (virgin and recycled) composites were found to increase and reach maximum at 30 per cent nano-CaCO3 loading, while the tensile strength decreased with increasing filler content. Thermal studies showed that the nano-CaCO3 filled PP samples exhibited a one-step degradation pattern and are thermally stable up to 450oC. The thermal stability of the samples was found to decrease following the addition of nano-CaCO3. SEM micrographs of the tensile fractured surfaces of composites of the nano-CaCO3 filled virgin and recycled PP revealed the presence of nano-CaCO3 agglomeration.
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Lee, Peter. "Blow molding behaviour of wood fibre-reinforced polypropylene composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ45434.pdf.
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Kim, Soeyeh. "Investigation of the characteristics of kenaf fibre reinforced polypropylene composites." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/11579.
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Includes abstract.Includes bibliographical references (leaves 135-140).
This research work focus on the characterisation of the mechanical and thermal properties of kenaf fibre reinforced polypropylene composites. The composites were fabricated by extrusion followed by injection and compression moulding. The effects of fibre content, coupling agent content (MAPP), different types of moulding processes and addition of filler materials (kenaf core) were observed through mechanical, thermal and microscopic testing.
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Tam, Mei San. "Study of sisal fiber-reinforced polypropylene, polyethylene and polypropylene/polyethylene blend composites prepared by compression molding." access abstract and table of contents access full-text, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?msc-ap-b21175123a.pdf.
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Thesis (M.Sc.)--City University of Hong Kong, 2005.At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 4, 2006) Includes bibliographical references.
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Ismail, Yob Saed Bin. "Structure/property relationships associated with woven glass fibres reinforced polypropylene composites." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/11902.
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The objective of this work was to examine the effect of thermal history during cooling from the melt on the degree of crystallinity, morphology and as well as the relationship between morphology/thermal history and mechanical properties of a 60:40 weight % mixture of woven glass fibres/PP composites. Mechanical properties studied include low velocity falling weight impact strength, flexural properties (modulus and strength) and interlaminar shear strength (ILSS). However the main focus was low velocity impact strength. The composite laminates were manufactured within a flat mould using a compression moulding press. Three thermal treatments were employed: isothermal crystallization from the melt in the range 106 to 156°C for 10, 30, 60 and 240 minutes in an oven; non-isothermal crystallization from the melt at rates varying from 0.67°C/Min. to 62.4°C/Min; and quenching from 190°C to rzooc and then annealing at 155, 160 and 165°C for one hour. The degree of crystallinity developed in the matrix polymer was determine using differential scanning calorimetry (DSC) and the matrix morphology was examined by reflected light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). TEM was used for quenched and annealed specimens.
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Wang, Shi-Wei. "Controlling the structure and properties of toughened and reinforced isotactic polypropylene." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0231/document.
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En tant que polymère de grande diffusion, les applications du polypropylène isotactique (PP) sont limitées par sa faible resistance au choc. D'après la relation structure - propriétés, sa résistance au choc peut être améliorée en contrôlant sa structure. Dans ces travaux, différents types d'agents nucléants ont été utilsés pour promouvoir la formation des cristaux de type bêta et de mélanges de deux PP de masses molaires différentes. Les propriétés mécaniques, le comportement à la rupture, et la morphologie cristalline ont été étudiés. Les influences du type et de la teneur en peroxyde et agent nucléant sur la morphologie cristalline et les propriétés mécaniques ont aussi été explorées. Un agent nucléant suporté sur des nanotubes de carbone multi-parois (MWCNT) a été utilisé pour modifier la structure cristalline du PP, ce qui a permis d'augumeter sa résistance au choc 7 fois comparée à celle du PP vierge et 3 fois comparée à celle du PP cristallisé en phase bêta. Cette importante augmentation en resistance au choc peut être attribuée à la formation des trans-cristaux de type bêta qui est favorisée par l?agent nucléant supporté sur les MWCNTAs a commodity polymer, the applications of isotactic polypropylene (PP) are limited by its low impact strength. Based on the structure-property relationship, its impact strength could be improved by controlling its structure. In this study, different kinds of nucleating agents were used to promote the formation of beta crystals of PP as well as mixtures of two PPs of different molar masses. The mechanical properties, fracture behaviour, and crystalline morphology were investigated. The effects of the type and content of the peroxide and nucleating agent on the crystalline structure and mechanical properties of the PP were also explored. A multi-walled carbon nanotude (MWCNT) supported nucleating agent was introduced to modify the crystalline structure of PP and the impact strength of the resulting PP was 7 times that of the pure PP and more than 3 times that of beta nucleated PP. The large increase in the impact strength was attributed to the formation of beta transcrystalline morphology which was promoted by the MWCT supported nucleating agent
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Magrini, Michael A. "Fiber reinforced thermoplastics for ballistic impact." Birmingham, Ala. : University of Alabama at Birmingham, 2010. https://www.mhsl.uab.edu/dt/2010m/magrini.pdf.
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Singh, Peter. "Molding behaviour and microstructure of injection molded short glass fiber reinforced polypropylene composites." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74240.
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Injection molded Short Glass Fiber Reinforced Thermoplastics (SFRTP) are widely used in industry because of advantages in material properties, availability, economics and ease of processing. The thermo-mechanical history experienced by the material during processing produces significantly anisotropic microstructural and consequently mechanical properties, varying not only spatially, but directionally.This work attempts to examine quantitatively various aspects of microstructure and the effect of processing conditions in SFRTP. The matrix phase properties, such as crystallinity, morphology and molecular orientation distribution, as well as the fiber phase microstructure such as concentration, length and orientation distributions have been analyzed quantitatively, and explained. Experimental techniques, including optical and electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, etc. have been used. The results indicate complex changes in microstructure from skin to core in the injection molded samples. Both matrix and fiber phase microstructures are affected by the basic thermal and flow processes that occur during the injection molding process. A first order model has been developed to predict fiber orientation distributions, which agree well with the experimental results.
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Amna, Ramzy Verfasser], and Gerhard [Akademischer Betreuer] [Ziegmann. "Recycling aspects of natural fiber reinforced polypropylene composites / Ramzy Amna ; Betreuer: Gerhard Ziegmann." Clausthal-Zellerfeld : Technische Universität Clausthal, 2018. http://d-nb.info/1231364289/34.
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Vaddi, Satya. "Flammability evaluation of glass fiber reinforced polypropylene and polyethylene with montmorillonite nanoclay additives." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/vaddi.pdf.
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Thesis (M.S.)--University of Alabama at Birmingham, 2008.Title from PDF title page (viewed Feb. 1, 2010). Additional advisors: Derrick R. Dean, Gregg M. Janowski, Selvum (Brian) Pillay (ad hoc). Includes bibliographical references (p. 76-82).
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Beg, Mohammad Dalour Hossen. "The Improvement of Interfacial Bonding, Weathering and Recycling of Wood Fibre Reinforced Polypropylene Composites." The University of Waikato, 2007. http://hdl.handle.net/10289/2553.
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This study deals with medium density wood fibre (MDF) and Kraft fibre reinforced polypropylene (PP) composites produced using extrusion followed by injection moulding. Initially, composites were produced with MDF fibre using 10, 20, 30, 40, 50 and 60 wt% fibre, and 1, 2, 3 and 4 wt% maleated polypropylene (MAPP) as a coupling agent. A fibre content of 50 wt% with 3 wt% MAPP was found to be optimum. Alkali treatment of fibre was carried out to improve the interfacial bonding. After treatment, fibre surface charge was found to increase, but single fibre tensile strength (TS) and Young's modulus were (YM) decreased. Alkali treatment reduced composite TS but increased YM. The effects of hemicellulose and residual lignin content were assessed with Kraft fibre (subjected to different stages of a standard Kraft pulping process and therefore consisting of different hemicellulose and residual lignin contents). Fibre surface charge was found to increase with decreasing residual lignin content. Composites containing higher amounts of lignin lead to lower TS and lower thermal stability. Composites were subjected to accelerated weathering for 1000 hours. TS and YM were found to decrease during weathering, and the extent of reduction was found to be higher for composites with higher residual lignin. The reduction of mechanical properties was found to be due to degradation of lignin and PP chain scission as evaluated by increase in PP crystallinity after weathering. As low lignin (bleached) Kraft fibre composites were found to provide superior mechanical properties, as well as more stable during accelerated weathering, further study including optimisation of MAPP content, effects of fibre contents, fibre length, fibre beating, hygrothermal ageing and recycling were carried out with bleached Kraft fibre. MAPP contents of 1, 2, 3, 4, 5, 7 and 10 wt% were used in Kraft fibre reinforced PP composites, and 3-5 wt% was found to be most favourable. Composite fibre content was varied between 30-50 wt%, and 40 wt% found to provide the maximum TS. To investigate the effects of fibre length on composites, fibre fractions of different length distribution were separated using a pressure screen. TS, YM and impact strength were found to decrease and failure strain (FS) increased with decreasing fibre length. To improve the interfacial bonding, the fibre was treated by mechanical beater. Fibre beating increased the TS of composites up to a certain point, beyond which TS decreased. Hygothermal ageing of composites was carried out by immersing specimens in distilled water at 30, 50 and 70 C over an 8-month period. Equilibrium moisture content and diffusion coefficient increased with increased fibre content in composites as well as with increased immersion temperature. Composites without coupling agent showed higher water uptake and diffusion coefficient than that of with coupling agent. After hygrothermal ageing the TS and YM decreased but FS and impact strength were found to increase. An investigation into the effects of recycling was carried out with composites containing either 40 wt% or 50 wt% fibre (bleached Kraft) with 4 wt% MAPP, and recycled up to eight times. For composites with 40 wt% fibre, TS and YM were found to decrease with increased recycling by up to 25% for TS and 17% for YM (after being recycled 8 times). Although TS was lower for virgin composites with 50 wt% fibre than for those with 40 wt% fibre, this initially increased with recycling by up to 14% (after being recycled 2 times), which was considered to be due to improved fibre dispersion, but then decreased with further recycling, and an overall 11% reduction of TS was found after recycling 8 times compared to the virgin composites. YM was higher for virgin composites with 50 wt% fibre than those with for 40 wt% fibre, and also initially increased with recycling but decreased upon further recycling. Recycling was found to increase thermal stability. The TS of composites made by combining recycled with virgin materials was also assessed. Hygrothermal ageing behaviour of recycled composites was also investigated by immersing specimens in distilled water at 50 C over a 9 month period. It was found that the diffusion coefficient and the equilibrium moisture contents of composites decreased with increased number of times the materials were recycled. After hygrothermal ageing, TS and YM of composites were found to decrease. However, the extent of reduction was found to decrease with increased recycling.
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Khoathane, MC, OC Vorster, and ER Sadiku. "Hemp Fiber-Reinforced 1-Pentene/Polypropylene Copolymer: The Effect of Fiber Loading on the Mechanical and Thermal Characteristics of the Composites." SAGE, 2008. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000586.
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One of the recent developments in composite technology in South Africa is the increasing use of natural fiber materials in the manufacture of plastic products. Most of the previous
work on natural fiber-reinforced composites has focused on sisal fiber as it was commercially available. In this study, the mechanical and thermal properties of composites made with locally produced hemp fibers, were compared with composites made with hemp fibers produced in France.
New commercial polypropylene random copolymer was used as matrix because it can be processed at lower temperatures when compared with other commercial propylene copolymers. The composites were produced by extrusion compounding and were further processed into tensile test bars by injection molding. Up to 30% fiber loading could be achieved. It was observed in all composites that increasing the amount of fiber resulted in an increase in tensile strength, elastic
modulus, and flexural strength and a decrease in impact strength. The thermal properties of the composites were analyzed by the thermogravimetric method. It was found that the fiber/PP
composites showed excellent properties when compared to fiber and the matrix separately. The addition of hemp fibers shifted the start of the degradation process towards higher temperatures.
The results obtained show that the mechanical and thermal properties of South African long hemp fiber composites compare favorably well with the French bleached and unbleached hemp fibers.
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Chaishome, Jedsada. "The effect of processing parameters on the mechanical properties of vacuum formed flax fibre reinforced polypropylene composites." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594739.
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The main aim of this thesis is to gain an improved understanding of the use and limitations of flax fibres as a reinforcement for thermoplastic composites manufactured by the vacuum forming process. The effect of process variables on void content and on mechanical properties of flax fibre/polypropylene composites has been investigated. An isothermal vacuum forming process has been studied and the following process parameters varied : consolidation time; fibre volume fraction; moisture content; reinforcement stacking sequence. The thermal degradation of untreated and alkaline treated flax fibres and its effect on the composite properties has been investigated using fourier transform infrared spectrometry (FTIR) and thermogravimetry (TG) techniques. Characterisation of the micro structure of failure surfaces following tensile testing of the composites has also been observed using scanning electron microscopy (SEM). The results of the investigation show that an increase in consolidation time at temperature and/or a reduction in fibre volume fraction reduces void content, as expected . By contrast and in spite of the reduction in voidage levels, mechanical tests show that an increase in consolidation time reduces ultimate tensile strength (UTS), strain to failure and impact strength of the composite. This reduction in properties is attributed to increased thermal degradation of the flax fibres and consequently the composite. Degradation manifests itself as hemicellulose and pectin decomposition in the fibres, particularly at low heating rates. Alkaline treatment was investigated as a potential method of improving the thermal stability of the fibres by reducing the low thermal stability hemicellulose and pectin components. Furthermore, such treatment improves the surface roughness of the fib res and results in an improved consolidation due to the reduction in void content. However, these positive effects did not significantly improve composite strength because of an apparent reduction in reinforcement volume fraction resulting from reduced fibre volume.
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Collier, Monty C. "Reclamation and Reprocessing of Thermotropic Liquid Crystalline Polymer from Composites of Polypropylene Reinforced with Liquid Crystalline Polymer." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36859.
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The composites industry can be positively influenced by composite materials that are processed faster, are lighter in weight, are higher in stiffness and strength, and that are more recyclable. There has been considerable interest in the use of thermotropic liquid crystalline polymers (TLCPs) to reinforce thermoplastic materials. In a novel process developed by Baird and coworkers, wholly thermoplastic composites are produced via a patented, dual extrusion process. This unique process yields a fiber which consists of numerous continuous fibrils of the liquid crystalline polymer encased in a thermoplastic matrix. These fibers have been used to form random mats and woven pre-forms, which have then been compression molded to form composite parts. Because of the high cost associated with these thermotropic liquid crystalline polymers and the desire to generate recyclable composites, a process was developed in this research to separate the liquid crystalline component from polypropylene (PP) composites.
The overall objectives of this work were to develop a process to reclaim the liquid crystalline component of these thermoplastic composites, to determine the effect the process had on the properties of the reclaimed liquid crystalline polymer, and finally to determine whether or not the reclaimed liquid crystalline polymer could be used again to generate a reinforcing component. An ancillary objective was to see if the polypropylene could also be reclaimed, and if it had further use as a polymeric resin.
In the present work, a novel process was developed that allows the liquid crystalline component to be reclaimed for further use in the composite material or in other applications that require thermotropic liquid crystalline polymers. The polypropylene component, which has undergone molecular weight reduction, can also be reclaimed by this process. This process consisted of using an organic peroxide and reactive extrusion to selectively degrade only the polypropylene, and not the thermotropic liquid crystalline polymer. The degraded polypropylene was selectively dissolved away from the liquid crystalline polymer by stirring the extruded melt in boiling mineral oil. The remaining solids, of thermotropic liquid crystalline polymer, were collected via centrifugation, cleaned of the mineral oil by boiling in kerosene, and then dried in a convection oven. The purity of the reclaimed thermotropic liquid crystalline polymer was determined by density measurements, while the physical properties of the reclaimed material were determined by rheological tests. The mechanical properties were determined via Instron testing of injection molded plaques made from mixtures of reclaimed material and pure thermotropic liquid crystalline polymer.
From this work, it was found that over 70 wt% of the thermotropic liquid crystalline polymer, DuPont HX8000, could be successfully separated from the polypropylene to a degree of 96.0%. From Instron testing, it was found that up to 40 wt% of the reclaimed HX8000 could be blended with the pure HX8000, with no loss in mechanical properties. Furthermore, it was seen that up to 83 % of the HX8000 component (40 wt%) of PP 6523 (60 wt%) composites could be replaced with reclaimed HX8000 without seeing any losses in mechanical properties. It was also found that the degraded polypropylene could be successfully separated, via centrifugation at a temperature of 253 K, and could be potentially used as resin for non-wovens. The projected material cost of the reclaimed HX8000, based on the ability to purchase and to process in bulk, was determined to be 90 % less than the virgin HX8000.Master of Science
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Kalyankar, Rahul R. "Natural fiber reinforced structural insulated panels for panelized construction." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2010r/kalyankar.pdf.
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Al-Kahtani, Salah Msfir. "The effects of hemp fibres on the mechanical and physical properties of E-glass fibres reinforced polypropylene (Twintex) composites." Thesis, University of Portsmouth, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530113.
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The main aim of this research is to investigate the mechanical and environmental properties of E-glass/polypropylene (Twintex) composite with and without natural fibres (Hemp) reinforcementA. serieso f lab testsw ere done to explain the impact damage characteristics of the composites were evaluated. The impact of mass applied started with 3.6 Kg and was incremented 3 Kg at a time to a maximum mass of 18.6 Kg. The effect of the impact damage and velocity was found to be significant- within the range of the velocities used. The absorbed impact energy significantly affected the impact performance of the Twintex panels. On the other hand, Twintex panels showed an ability to confine the damage zone and hence, to increase the damage tolerance of the panels. The results of impact were analysed using C-Scan. They significantly show that with the increase of mass the area of damage increases accordingly. The flexural properties of composite samples were evaluated by 3-point bending test methods. In contrast, the loads for sample's deformation in three-point bending test proved to be less when high-impact loaded samples were used. For the samples without hemp, the highest flexural stress was 317.616 MPa and the lowest was 116.552 MPa. The highest flexural modulus was 9937.63 MPa and the lowest was 4439.898 MPa. The effect of the flexural percentage of the load decreases with the increase of mass. The load decrease from sample 1 to sample 7, which indicated a loss in flexural strength by 63.03% and a loss in flexural modulus by 55.32%. With hemp reinforcement the highest flexural stress was found 189.092 MPa and the lowest was 101.763 MPa. The highest flexural modulus was found 10299.37 MPa and the lowest was 2437.73 MPa. The effect of the flexural percentage of the load decreases with the increase of mass. Twintex plus hemp retained 85.81 % of the original flexural strength it means that adding of hemp into the Twintex reduces the strength of the sample by 2.01 %. IV Abstract Tensile test results show the tangent modulus for the Twintex has reach to 1967.79 MPa, however adding hemp into the Twintex decrease the tangent modulus by 1.465% times. This is meant that the Twintex plus hemp makes the material weaker and softer. The Twintex plus hemp will be weaker by 30.765%. The SEM evaluation also shows that by increasing the impact load the state of the damage becomes more severe. There arc more instances of brittle and catastrophic fibre damages with high impact load. The Twintex plus hemp samples gained in weight, as expected, by an average of 2.64%. This 2.64% increase, assuming that the hemp absorbs all the water and not the polypropylene, means that the fibres increased weight by approximately 8.2%. Along with this increase in weight, the fibres also expanded due to the water absorption. After the water bath the samples lost only 2.5% of their flexural strength and an insignificant loss in flexural modulus. The addition of hemp caused a 35.4% reduction in the flexural modulus of the samples. This means that the samples with hemp became more elastic, deforming more than samples without the hemp layers. The effect of water absorption seemed to have little effect on any of the samples, with the largest effect being a 5.4% reduction in water boiled Twintex and hemp samples. Twintex obtains its highest flexural modulus properties from the glass fibres in the matrix. A reduction (35.4%) suggests that the reinforcement properties of the glass fibres are being reduced due to the incorporation of the hemp. This could be due to the hemp fibres taking away matrix material from the glass fibres in the centre of the sample. Creep and Stress relaxation properties of the sandwich panels with and without natural reinforcements were investigated and compared under different temperatures such as 30 °C, 40 °C, 50 °C, 60 °C. Melting point of both materials was determined. These qualitative and quantitative conclusions can be drawn regarding the use of hemp as reinforcement in Twintex sandwich panel.
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Elsabbagh, Ahmed [Verfasser], and Gerhard [Akademischer Betreuer] Ziegmann. "Processing and optimising the mechanical and physical properties of natural fibre reinforced polypropylene composites / Ahmed Elsabbagh ; Betreuer: Gerhard Ziegmann." Clausthal-Zellerfeld : Technische Universität Clausthal, 2017. http://d-nb.info/1231364947/34.
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Krishnaiah, Prakash. "Development of polylactide and polypropylene composites reinforced with sisal fibres and halloysite nanotubes for automotive and structural engineering applications." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43498/.
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In recent decades, scientific research giving more attention to the development of bio-based polymer composites due to the extensive usage of petroleum based fillers as well as polymer matrices for the generation of polymer composites. It is a well-known fact that the petroleum derived polymer composites raise inevitable issues such as environmental pollution, waste management and depletion of petroleum resources etc. So it is important to develop fully or partially biodegradable polymer composites without compromising the mechanical, physical and thermal properties which are required for the end use applications. In this investigation, two different types of filler materials such as sisal fibres and halloysite nanotubes were used to prepare PLA polymer composites and their morphology, physical, mechanical, dynamic mechanical, thermal, water absorption and biodegradable properties were studied. This work also involves the preparation and properties of polypropylene composites reinforced with sisal fibres and halloysite nanotubes to compare the mechanical and thermal properties with PLA composites. First, surface treatment was performed for sisal fibres in order to remove the amorphous materials such as hemicellulose, lignin and pectin from the surface of the fibres which enhances the fibre-matrix interfacial strength and mechanical properties of the fibres and their polymer composites. Sisal fibres were subjected to different surface treatments such as alkali, high intensity ultrasound (HIU), and the combination of alkali and HIU and their effects on the morphology, fibre diameter, moisture absorption, mechanical and thermal properties of untreated and surface treated sisal fibres were studied. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FE-SEM) results confirmed the removal of amorphous materials after the combined treatments of alkali and ultrasound. Moisture absorption and diameter of the sisal fibres were significantly reduced by 40 and 200% respectively after the combination of alkali and HIU treatment as compared to untreated sisal fibres. TGA results revealed that the thermal stability of sisal fibres obtained with the combination of alkali and HIU treatment significantly increased by 38.5 oC as compared to the untreated fibres. Tensile properties of single fibre showed a reduction in the tensile strength and modulus by 25% and 26% respectively as compared to the untreated sisal fibre owing to surface treatments. A reduction in the tensile properties is mainly due to the removal of amorphous materials from the surface of sisal fibres which act as binding materials for cellulose. Second, the effect of different surface treatments on the morphology, mechanical, thermal, water absorption and biodegradable properties of sisal fibres reinforced PLA (SF/PLA) composites has been investigated. For this, different ratio of untreated and surface treated sisal fibres was mixed with PLA polymer matrix by using an internal mixer. Compounded materials from the internal mixer were subjected to compression moulding to prepare the test specimens. FE-SEM analysis confirmed the good dispersion of different surface treated SF in the PLA composites. The tensile strength and modulus increased by 10 and 75.4% for 15 wt% and 30 wt% of fibre loading respectively with the combined treatment of alkali and HIU PLA composites as compared to the untreated fibre reinforced PLA composites. Young’s modulus of the composites has also been predicted by using the theoretical models which fit well to the obtained experimental values. Dynamic-mechanical analysis (DMA) revealed that the combination of alkali and HIU treated SF/PLA composites showed an increase in the storage modulus by 15% and 30% as compared to the untreated fibre composites and pure PLA respectively. TGA and DSC analysis revealed that the thermal stability and crystallinity increased significantly for the PLA composites reinforced with sisal fibres of combined treatment of alkali and HIU. Water absorption study showed a considerable reduction in the water absorption and coefficient of diffusion by 136% and 130% respectively for the combination of alkali and HIU treated SF/PLA composites as compared to untreated SF/PLA composites. The degradation of SF/PLA composites was studied by composting the samples into the soil. A significant weight loss of 17.87% could be observed for the addition of 30 wt% of untreated SF/PLA composites after soil composting for 120 days. Apart from sisal fibres, halloysite (Hal) nanotubes were also used as reinforcement fillers to study their effectiveness in improving the mechanical and thermal properties of PLA nanocomposites. Hal nanotubes were surface modified with 3-aminopropyltriethoxysilane (APTES) to enhance the surface interaction of Hal nanotubes with PLA and to achieve good dispersion of Hal nanotubes across the PLA matrix. Nitrogen adsorption-desorption, FTIR and TGA analysis results were confirmed the successful modification of Hal nanotubes surface with APTES. The different wt% of unmodified and APTES modified Hal-PLA nanocomposites were prepared by using internal mixer and compression moulding machine. The resultant Hal-PLA nanocomposites were characterized for their morphology, thermal, mechanical and dynamic-mechanical properties. Tensile strength increased to 62.6 MPa with the addition of 4 wt% of APTES modified Hal-PLA nanocomposites which is 26.5% higher than pure PLA and 15% higher than unmodified (4 wt%) Hal-PLA nanocomposites. Impact strength of 4 wt% APTES modified Hal-PLA nanocomposites increased by 20% and 40% as compared to unmodified Hal-PLA nanocomposites and the pure PLA respectively. TGA analysis revealed that the thermal stability increased significantly by 17 oC with the addition of 4 wt % of APTES modified Hal nanotubes onto PLA. Storage modulus increased by more than 10% with the addition of 4 wt% of APTES modified Hal nanotubes as compared to pure PLA. To compare the PLA composites with conventional polymer matrix composites, composites of polypropylene (PP) were prepared by reinforcing with sisal fibres and Hal nanotubes and the effect of surface treatment of sisal fibres and surface modification of Hal nanotubes on the mechanical and thermal properties of SF/PP and Hal-PP nanocomposites were studied. Tensile properties were increased for the combined treated SF/PP composites as compared to the untreated and pure PP. Tensile modulus and strength increased by more than 50% and 10% respectively as compared to the untreated SF/PP composites. TGA and DSC results revealed that the combination of alkali and HIU treatments increased the thermal stability and crystallinity by 8 oC and 8% respectively as compared to untreated SF/PP composites. DMA analysis confirmed the significant enhancement of storage modulus for the combined treated SF/PP composites by 50% as compared to pure PP. Mechanical and thermal properties were studied for unmodified and APTES modified Hal nanotubes reinforced PP nanocomposites. The investigations suggest that the mechanical properties of APTES modified Hal-PP nanocomposites were found to be superior to the unmodified Hal-PP nanocomposites. The tensile strength and modulus increased by 31 and 72% with the addition of 6 wt% of APTES modified Hal-PP nanocomposites as compared to pure PP. Impact strength also increased by 44% than pure PP with 6 wt% loading of APTES modified Hal nanotubes. Thermal analysis revealed that the thermal stability and percentage crystallinity increased by 15 oC and 22% respectively for the Hal-PP nanocomposites with surface modification by APTES. DMA analysis shows the improved storage modulus by 28% as compared to pure PP. Based on the present work, it can be said that the sisal fibres and Hal nanotubes have potential as reinforcing materials in the generation of fully bio-based polymer composites.However, surface treatments and/or modification were playing an important role in order to tune the required mechanical and thermal properties of the polymer composites. This study also proved that in comparison to the conventional polymer matrix materials such as PP, PLA is a strong competitor with respect to its good mechanical properties and improved thermal stability apart from the fact that PLA is one of the best known biodegradable and biocompatible polymer matrices in the current market to use not only in medical application, but also in various commercial applications such as packaging, automotive and home appliances.
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De, Souza Rios Alexandre. "Mechanical behavior of recycled polypropylene reinforced by coconut fibers using X-ray tomography and digital image correlation." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLN023/document.
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L’objectif de ce travail est de caractériser le comportement mécanique de composites constitués à de matrices polymériques renforcées par des fibres naturelles. Les matériaux étudiés dans cette thèse sont le polypropylène pour la matrice et les fibres de coco pour les renforts. La caractérisation morphologique et mécanique de ces matériaux est entreprise grâce à l’usage de la microscopie électronique à balayage, la tomographie aux rayons X, la corrélation d’images numériques et la thermographie infrarouge. Dans une première partie, on a étudié en détail les fibres de coco dans trois états différents: à l’état naturel et après traitement chimique suivi ou non de séchage. Les fibres ont été observées en tomographie et leurs caractéristiques essentielles définies. Par ailleurs des essais mécaniques in-situ dans un microscope électronique à balayage ont été conduits pour l’obtention de leurs propriétés mécaniques. Il a quasi été procédé à la caractérisation mécanique du comportement de tissus de fibre en vue de leur utilisation dans un composite. Dans une seconde partie, le comportement mécanique du polypropylène (à l’état vierge ou recyclé) a été analysé grâce à des essais de traction à déplacement imposé et à diverses vitesses de chargement. Ces essais ont été instrumentés pour des mesures de champs de déplacement et de températures, les premiers servant à mesurer les états de déformation, la progression de l’endommagement et observer les modes de rupture du matériau. L’effet du recyclage est souligné et en particulier la dégradation des propriétés mécaniques. Les caractéristiques complètes (élasticité, pic et plateau et endommagement) et l’effet de la vitesse sur celles-ci sont exhibées pour les deux états. Dans la dernière partie du travail, on s’est intéressé au comportement du composite considérant la matrice à l’état vierge ou dans l’état recyclé. Les caractéristiques obtenues sont discutées en soulignant l’influence du mode d’élaboration utilisé et l’apport des fibres de cocoThe objective of this work is to characterize the mechanical behavior of composites made with recycled polymeric matrices reinforced with natural fibers. The materials studied in this thesis are the polypropylene matrix and the coconut fibers for reinforcement. The morphological and mechanical characterization of these materials is undertaken with the use of scanning electron microscopy, X-ray tomography, the digital image correlation and infrared thermography.In the first part, we studied in detail the coconut fibers in three different states: in its natural state and after chemical treatment followed or not drying. The fibers were observed in tomography and their essential characteristics defined. Furthermore in situ mechanical testing in a scanning electron microscope were conducted to obtain their mechanical properties. It has almost been carried out the mechanical characterization fabrics of the behavior for use in a composite. In a second part, the mechanical behavior of polypropylene (virgin or recycled state) was analyzed by tensile testing at imposed displacement and various charging speeds. These tests were instrumented for measurement of displacement fields and temperatures, the first to measure the deformation conditions, the progression of the damage and observe the failure modes of the material. The effect of recycling is particularly pointed out and degradation of mechanical properties. Complete specifications (elasticity, peak and shelf and damage) and the effect of speed on them are exhibited for both states. In the last part of the work, it was interested in the behavior of the composite matrix considering the blank state or in the recycled state. The characteristics obtained are discussed emphasizing the influence of the method of production used and the contribution of coconut fibers
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Beckermann, Gareth. "Performance of Hemp-Fibre Reinforced Polypropylene Composite Materials." The University of Waikato, 2007. http://hdl.handle.net/10289/2543.
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Increasing worldwide environmental awareness is encouraging scientific research into the development of cheaper, more environmentally friendly and more sustainable construction and packaging materials. Natural fibre reinforced thermoplastic composites are strong, stiff, lightweight and recyclable, and have the potential to meet this need. Industrial hemp fibre is amongst the strongest of the natural fibres available, and possesses a similar specific stiffness to E-glass, but with additional benefits such as low cost and low production energy requirements. The favourable mechanical properties of hemp, however, have yet to be transferred successfully to thermoplastic-matrix composite materials. The aim of this thesis was to achieve a greater understanding of the various parameters that contribute to composite strength and stiffness, and to manipulate these parameters in order to produce an improved hemp fibre reinforced polypropylene composite material. Hemp fibre was alkali treated at elevated temperatures in a small pressure vessel with either a solution of 10wt% NaOH or 5wt% NaOH / 2wt% Na2SO3. Single fibre tensile tests were performed on treated and untreated fibres, and it was found that the NaOH/Na2SO3 treatment produced the strongest and stiffest fibres with a good level of fibre separation. Lignin tests revealed that both alkali treatments were effective in the removal of lignin from hemp fibre, and XRD analysis showed that both alkali treatments resulted in increases in the hemp fibre crystallinity index. TGA and DTA analysis showed that the alkali fibre treatments improved the thermal stability of the treated hemp fibre when compared to the untreated fibre. Alkali treated hemp fibre, polypropylene and a maleic anhydride modified polypropylene (MAPP) coupling agent were compounded in a twin-screw extruder, and injection moulded into composite tensile test specimens. A range of composites with different fibre and MAPP contents were produced and tested. Tensile tests revealed that the optimum composite consisted of polypropylene with 40wt% NaOH/Na2SO3 treated hemp fibre and 4wt% MAPP, and had a tensile strength of 50.5 MPa and a Young's modulus of 5.31 GPa, respectively. The effect of MAPP on the fibre/matrix interface of NaOH/Na2SO3 treated hemp fibre/polypropylene composites was assessed by means of the single fibre fragmentation test. A composite consisting of NaOH/Na2SO3 treated fibres in a matrix of 4wt% MAPP and polypropylene was found to have a critical fibre length of 0.83mm and an interfacial shear strength of 16.1 MPa. The effects of MAPP on the composite fracture mechanisms were evaluated by means of SEM microscopy. TGA and DTA analysis showed that untreated hemp fibre composites and NaOH/Na2SO3 treated hemp fibre composites, each with a matrix of 4% MAPP and polypropylene, were less thermally stable than the polypropylene matrix alone. The Bowyer-Bader model was used to model the strength of an injection moulded composite with a normal fibre length distribution, consisting of 40wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene. A theoretical composite tensile strength of 149 MPa was obtained from the model, based on the assumption that all the fibres were axially aligned in the composite. Composites with long, axially aligned fibres were produced using a novel solution mixing technique, where the polymer matrix and MAPP coupling agent were dissolved in a solvent and then precipitated inside an aligned fibre mat. Significant improvements in tensile strength and Young's modulus were achieved for solution mixed composites compared to composites produced by means of extrusion and injection moulding. The strongest solution mixed composite had a tensile strength of 84.7 MPa, and consisted of 56wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene; and the stiffest injection moulded composite had a Young's modulus of 16.0 GPa, and consisted of 63wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene.
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Lindhagen, Johan. "Notch sensitivity and failure of glass mat reinforced polypropylene." Licentiate thesis, Luleå tekniska universitet, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18077.
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Briskham, Paul Graham. "Strong and durable fusion bonding of glass reinforced polypropylene to pretreated aluminium." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342549.
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Sultangaliyeva, Fariza. "Formulation of fluid fire-resistant fiber-reinforced cementitious composite : Application to radioactive waste disposal." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3041.
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Le but de ce travail est de développer un béton fluide résistant au feu renforcé en fibres de polypropylène pour les colis de stockage des déchets radioactifs de moyenne activité à vie longue. Le défi de ce travail consiste à utilizer des fibres de polypropylène qui, même ajoutées en petite quantité, améliorent la résistance au feu mais diminuent de manière significative la maniabilité des bétons frais. Des essais à l’échelle du laboratoire sont effectués afin d’évaluer les comportements rhéologique et à haute température des matériaux cimentaires contenant des fibres de polypropylène. Dans la première partie, une étude du comportement rhéologique des matériaux cimentaires avec des fibres de polypropylène a été réalisée. Le but de cette étude est d’étudier l’influence de ces fibres sur le seuil d’écoulement des pâtes de ciment et des mortiers. Un modèle qui permet d’évaluer la quantité de pâte supplémentaire nécessaire pour compenser l’effet des fibres de polypropylène en fonction de la fluidité du béton frais a été développé.Ensuite, une étude expérimentale et numérique sur le comportement des matériaux cimentaires avec des fibres de polypropylène à haute température a été réalisée afin d’optimiser le choix des fibres pour améliorer la stabilité thermique d’un matériau cimentaire. Des essais de perméabilité résiduelle radiale et des essais feu sur les trois matériaux avec squelettes granulaires différents contenant des fibres de polypropylène de différentes géométries et dosages ont été réalisés dans un but de sélectionner une géométrie et un dosage optimal des fibres. Puis, des simulations thermomécaniques ont été développées à l’échelle macroscopique et mésoscopique. Le choix du diamètre, de la longueur et du dosage des fibres a été fait en fonction de la taille maximale des granulats.Finalement, une méthode de formulation du béton autoplaçant avec des fibres de polypropylène optimisé à la fois du point de vue de la rhéologie et de la résistance au feu a été présentée. Avec cette méthode, la conformité aux critères imposés sur les propriétés à l’état frais et à l’état durci du béton est vérifiée. Des éprouvettes de bétons sont testées sous chargement mécanique uniaxial et, en fonction des résultats, les formulations finales sont sélectionnées pour les futurs essais feu à l’échelle plus importanteThe aim of the thesis is to design a self-compacting concrete with polypropylene fibers resistant to fire for a use in storage containers of medium activity long-lived waste. The challenge of the work is presented by the use of polypropylene fibers that enhance fire resistance but drastically diminish workability of concrete even when added at small volume fractions. Tests on laboratory scale are conducted with a purpose of evaluating rheological behavior and high temperature behavior of cementitious materials containing polypropylene fibers.In the first part, a study of rheological behavior of cement-based materials containing polypropylene fibers was done. The aim of this study is to investigate the influence of polypropylene fibers on the yield stress of cement pastes and mortars. A model is proposed to be able to evaluate the quantity of paste necessary to compensate the addition of polypropylene fibres according the fluidity of fresh concrete.Then an experimental and numerical investigation of behavior of cementitious materials with polypropylene fibers at high temperature was done so as to optimize the choice of polypropylene fibers for cementitious material to improve its thermal stability. Three different cementitious materials with three different granular skeleton containing various polypropylene fiber geometries and dosages were tested (residual radial permeability test and fire test) in order to select an optimal fiber geometry and dosage. Then thermomechanical computations was developped at maco and meso scale. Then, a choice of diameter, length and dosage of fibres is proposed according to the maximum size of gravels.Finally, a method of concrete formulation with polypropylene fibers optimized from perspectives of rheology and resistance to fire is presented. In this method, fresh and hardened state properties are verified to ensure an accordance with performance criteria specified by the project. At the end, designed mixes were tested in fire tests conducted on uniaxially compressed prisms and, based on outcomes, final mixes are selected for further fire tests on higher scale concrete
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Modh, Haresh A. "Chemical treatment and adhesion in internally reinforced rayon fibers." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182867766.
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Han, Hongchang. "Study of agro-composite hemp/polypropylene : treatment of fibers, morphological and mechanical characterization." Thesis, Troyes, 2015. http://www.theses.fr/2015TROY0002/document.
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L’utilisation des fibres végétales dans les polymères composites suscite de nombreuses investigations. Avant de mélanger les fibres végétales dans le polymère, un traitement chimique peut être effectué permettant de réduire l’hydrophilicité des fibres et d’améliorer l'adhérence à l’interface fibre/matrice. Dans cette thèse, l'eau et l'alcali sont utilisés d'abord pour traiter les fibres de chanvre, puis trois agents silane : 3-(triméthoxysilyl)propyl méthacrylate (MPS), N-[3- (triméthoxysilyl)propyl] aniline (PAPS) et (3-Aminopropyl)-triéthoxysilane (APS), sont utilisés pour modifier plus ou moins la surface des fibres de chanvre. Ces fibres traitées ou modifiées sont ensuite mélangées avec le polypropylène (PP) pour la fabrication des composites. Les effets de ces différents traitements sur la structure, les composants et l’hydrophilicité des fibres, et les propriétés mécaniques de ces composites sont mis en évidence. Nous avons étudié ensuite l’effet de vieillissement sur leurs comportements mécaniques, notamment l'humidité, la température et le rayonnement ultraviolet. Les résultats ont montré que le traitement de fibres par l'eau et l’alcali a des effets considérables sur la structure de fibres, les propriétés mécaniques et la durabilité des composites renforcés. La modification par l'agent de silane a une influence moins importante sur la structure des fibres, pourtant son groupe fonctionnel a une influence significative sur les propriétés mécaniques et la résistance au vieillissement des composites renforcésUsing agro fiber as reinforcement of polymer com-posites attracts numerous investigations due to the good mechanical properties and environmental benefits. Prior to blend agro fiber with polymer, chemical treatment can be employed to treat agro fiber for the purpose of reducing the hydrophilicity of fiber and improving the interfacial adhesion fi-ber/polymer matrix. In this thesis, water and alkali are utilized to treat hemp fiber firstly and then three silane agent as 3-(Trimethoxysilyl)propyl methacry-late (MPS), N-[3-(Trimethoxysilyl)propyl]aniline (PAPS) and (3-Aminopropyl)-triethoxysilane (APS) are employed to modify the hemp fiber surface. These treated or modified fibers are blended respectively with polypropylene (PP) to fabricate the hemp fiber/PP composites. The effects of these different treatments on the structure, components and hydro-philicity of fiber, and the mechanical properties of the reinforced PP composites are studied. Moreover, the accelerated ageing experiments including humidity, temperature and ultraviolet of the reinforced PP composites are conducted. The results showed that the fiber treatment of water and alkali has a considerable effect on fiber structure, mechanical properties and durability of the reinforced compo-sites. The silane agent modification of fiber has less influence on the fiber structure but its functional group has great influence on the mechanical proper-ties and ageing resistance of the reinforced compo-sites
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Imaddahen, Amine. "Étude expérimentale multi-échelle et modélisation hybride prédictive du comportement, de l'endommagement et de la durée de vie en fatigue d’un matériau composite polypropylène / fibres de verre." Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE063.
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L’objectif final de ce travail est de proposer un outil numérique capable de prédire l'endommagement et la durée de vie en fatigue des matériaux et structures en composite à matrice thermoplastique. Pour ce faire, une étude expérimentale multi-échelle du matériaux PPGF40 (polypropylène chargé en fibre de verre à 40% en masse) est réalisée. Une analyse qualitative, mais aussi quantitative des différents mécanismes d’endommagement se produisant lors d’une sollicitation mécanique a été réalisée à travers des essais de flexion trois points in situ MEB, des essais de fatigue interrompus et des observations des faciès de rupture en monotone et en fatigue. A la lumière de ces essais nous avons conclu que la décohésion de l’interface fibre-matrice et la propagation des fissures à travers les interfaces apparait être le phénomène prépondérant menant à la ruine du matériau et cela indépendamment de l’orientation des fibres et du mode de sollicitation monotone ou fatigue. La démarche hybride proposée est basée sur un modèle micromécanique / phénoménologique permettant de prendre en compte l’endommagement à l’interface fibre-matrice et la plasticité de la matrice. Pour ce faire, un critère local statistique d’endommagement à l’interface fibre-matrice est introduit dans un modèle de Mori et Tanaka et la linéarisation du comportement plastique de la matrice est réalisée pas à pas, en utilisant une approche en champs moyens avec une formulation sécante. Le modèle micromécanique utilisé permet alors de prédire le comportement du matériau sous chargement monotone et notamment la première perte de rigidité en fatigue. L’analyse des résultats montre que cette dernière est directement liée à la durée de vie en fatigue du matériau. Ainsi, une méthodologie prédictive de la durée de vie est proposée et validée pour différentes configurations microstructurales. Un critère de rupture en fatigue est proposé en fonction du nombre de cyclesThe main objective of this work, is to provide a numerical tool, capable of predicting the damage and fatigue life of thermoplastic matrix composites materials and structures. To do this, a multi-scale experimental study of the PPGF40 material (polypropylene loaded with 40% by mass of glass fiber) is carried out. A qualitative, but also a quantitative analysis of the various damage mechanisms occurring during mechanical loading was carried out through in-situ three-points SEM bending tests, interrupted fatigue tests and observations of fracture faces in monotonic and cyclic loading. In the light of these tests, we concluded that the decohesion of the fiber-matrix interface, and the propagation of cracks through the interfaces, appears to be, the predominant damage phenomenon leading to the fracture of the material and that, regardless of the orientation of the fibers and the loading mode. The proposed hybrid approach is based on a micromechanical / phenomenological model taking into account the damage at the fiber / matrix interface and the plasticity of the matrix. To do this, a local statistical criterion of damage at the fiber-matrix interface is introduced into a Mori and Tanaka model, and the linearization of the plastic behavior of the matrix is done step by step, using the mean field approach with a secant formulation. The micromechanical model used then, makes it possible to predict the behavior of the material under monotonic loading, and in particular the first stiffness loss during the fatigue. Analysis of the experimental results shows that the latter is directly related to the fatigue life of the material. Thus, a predictive methodology of the fatigue life is proposed and validated for various microstructural configurations. A fatigue failure criterion is proposed according to the number of cycles
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Počekajlo, Václav. "Trvanlivost sanačních hmot pro železobetonové konstrukce s vyšší odolnosti proti požáru." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227675.
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This dissertation deals with the study of durability and degradation repair mortars for reinforced concrete structures. In its theoretical part, there are the research findings on the behavior of repair mortars exposed to corrosive environments with different exposure time and selected high temperatures. Processes occurring in repair mortars during their loading at high temperatures or when exposed to chemically aggressive environments are described, We can find recipes designed for cementitious binder based with a specific replacement using slag or fly ash in its practical part. The object of the research was to determine the durability of the proposed repair mortars, and determine their suitability for use on concrete structures, which may be exposed to a synergistic effect of chemically aggressive environments with high temperatures simulating fire.
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LIN, YU-CHEN, and 林雨辰. "Preparation and analysis of flax fiber-reinforced polypropylene composites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/41987624408938804372.
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碩士明志科技大學
化學工程系碩士班
104
This study adopts the compounding method using a Banbury mixer to blend polypropylene (PP) and flax fibers to obtain the natural fiber-reinforced PP composites. Test samples for mechanical testing were prepared by injection molding. The polar flax fibers have low compatibility with non-polar polymer matrices such as PP. By this token, treatment of flax fibers is beneficial in order to promote interfacial adhesion. The surface modification of flax fibers was carried out using four different functional groups of silane coupling agents and the modified flax fibers were characterized by Fourier transform infrared spectroscopy. The morphology of the modified fibers was examined by scanning electron microscope. The result shows that the hydrolysis step of BRB276 and BRB258 is difficult to proceed unless adding acetic acid as catalyst. BRB919 is easy to proceed hydrolysis reaction without adding catalyst. The thermal stability of the composites was examined by thermogravimetric analysis. The thermal stability of the composites with BRB919 treated flax fibers is better than that of the others. This may be due to the flax fibers modified by BRB919 could improve the interfacial force between PP and flax fibers. According to the tensile test, adding flax fibers in PP could increase the tensile strength and Young’s modulus. However, the elongation of the composites was decreased compared to neat PP. The impact strength of the composites with silane treated fibers is better than those without silane treated fiber.
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SU, BO-YU, and 蘇柏宇. "A Study of Woven Jute Fiber Cloth Reinforced Polypropylene Composites." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/tq3taw.
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碩士朝陽科技大學
應用化學系
105
In this study, woven jute fiber cloth (Jf) was used to reinforce polypropylene (PP), and a commercially available flame retardant was added to increase the application PP. Maleic anhydride grafted polypropylene (MAPP) was added as a compatibilizer. Moreover, Jf was chemically treated and modified by 3-Aminopropyltriethoxysilane to enhance the properties of the composites. The results showed that the absorption peaks of C-Br and Sb2O3 were found in the FTIR spectrum of flame retardant. And the Jf is composed of jute yarn, PE fiber and PP/PE blending fiber. TGA analysis revealed that the decomposition temperatures (Td5 and Td20) of the composites were increased by improving the compatibility of the composites, and char yield was also increased. The results of tensile and impact tests showed that PP/MA/BJf exhibited the best tensile and impact strengths. The results of UL-94 test showed that the flame retardancy of the flame retardant containing composite materials can achieve the highest level (V-0). SEM analysis can be observed that the compatibility between Jf and PP was improved by the chemical treatment of Jf. Based on the above results, Jf reinforced PP composite materials can reinforce PP with low cost, and increase the applications of PP.
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Liu, Ya-Shin, and 劉雅馨. "Mechanical Properties of Braided Jute/Polypropylene Fabrics Reinforced Epoxy Composites." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18557376547703416766.
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碩士萬能科技大學
材料科技研究所
99
The main objective of this thesis was to study the mechanical characteristics of Jute/Polypropylene braided fabric reinforced epoxy composites. A tubular braiding machine was used to braid the jute yarns and polypropylene (PP) yarns to get hybrid jute/PP tapes. The tapes were, then, used as weft and warp yarns, which supplied to a weaving loom, to fabricate reinforced fabrics. The fabrics are plain woven construction. Three reinforced fabrics (braided jute tape plain fabric, braided polypropylene tape plain fabric and co-braid jute/polypropylene tape plain fabric) had been developed in this experiment. After finished the weaving procedure, the produced fabrics impregnated with epoxy resin to get the braided tape fabrics reinforced composites. The co-braid jute/polypropylene tape plain fabrics were, also, heated and pressed onto a hot-press machine to fabricate thermoplastic composites. A material test system was used to study the tensile, compressive and flexural properties of the composites. In addition, the iMPact properties were evaluated by an Izod iMPacting machine. The failure phenomenon of the composites was, also, discussed, in the current experiment. Experimental results revealed that the co-braid structure of Jute/PP fabric improved the compressive resistance of the composites. Furthermore, adding PP braided reinforced fabrics increases composites toughness and yields better energy absorption in coMParison with pure epoxy sample.
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Wu, Pei-Yu, and 吳珮瑜. "A Study of Jute Fiber/ Biomass waste Reinforced Polypropylene (PP) Composites." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/49943027714600776853.
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碩士朝陽科技大學
應用化學系
103
In this study, the matrix and reinforcements were melting blended to obtain the composites. The matrix was polypropylene (PP), and the reinforcements were jute fiber, kenaf powder or rice husk powder. The addition amount of reinforcements were 20 to 40 wt%. In addition, the jute fiber was modified by silane coupling agent (3-Aminopropyltriethoxysilane), and maleic anhydride grafted polypropylene (MAPP) was added as compatibilizer to improve the compatibility between reinforcements and PP, then enhanced the mechanical and thermal properties of the composites. The results reveal that the composites containing 30wt% of jute fiber/kenaf powder possessed the best properties. Moreover, the composites containing 30wt% of jute fiber/rice husk powder were prepared and compared with the jute fiber/kenaf powder ones. The results reveal that the higher heat distortion temperature (about 150.90 ~ 153.05 ℃) were obtained when the ratio of jute fiber and kenaf powder is 1: 3. However, the heat distortion temperatures of jute fiber/rice husk powder composites were increased with increasing content of jute fiber. The tensile and impact strengths of the composites could be increased about 46.63% and 61.86% as compared with those of pure PP. The results of thermal analysis reveal that the heat resistance of the PP was improved by the addition of the reinforcements. Microscopic analysis indicate that the dispersion of jute fiber in the matrix was well when the composites containing 30wt% of reinforcements. As well as enhancing the mechanical properties and thermal stability, the reinforced composites are more environmentally friendly than the artificial additive-reinforced ones. The waste from the kenaf and rice husk is effectively reduced and re-used, and the cost of materials can be reduced.
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"Effect of Fiber Morphology on Tensile Properties of Polypropylene Cement Composites." Master's thesis, 2017. http://hdl.handle.net/2286/R.I.44218.
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abstract: The main objective of this study is to investigate the effect of polypropylene fiber morphology on the tensile response of cementitious composites. Two proprietary polypropylene fibers manufactured by BASF – MAC 2200CB, a crimped monofilament macro fiber and MF40, a bundled multi filament polypropylene made up of 500 filaments,40-micron diameter each were compared. The stiff structure and crimped geometry of MAC 2200 CB was studied in comparison with the multifilament MF40, which provide a higher surface area and a bundled fiber effect. Uniaxial tensile tests were performed on individual fibers to study fiber strength and failure pattern at three different gage lengths. The interaction of these 2 fibers with cement matrix was studied under varying strain rate, embedded fiber length and matrix mixes by a series of quassi - static fiber pullout tests. Unidirectional filament wound composite laminates were manufactures with the two fibers and only MF40 woven textiles were used to manufacture MF40 textile reinforced composites. The mechanical behavior of polypropylene fiber and textile reinforced cementitious composites subjected to static tensile loading with the effects of fiber type and dosage, textile weave and dosage, matrix formulations, processing techniques etc. is studied. Evolution of distributed cracking mechanism and local strain fields was documented using digital image correlation (DIC) and correlated with the tensile response and stiffness degradation. VIC 3D-7, commercial software developed by Correlated Solutions, Inc. was used to run the DIC analysis for the tensile tests on laminates. The DIC technique was further used for automated determination of crack density, crack spacing, and characterizing damage evolution.Dissertation/Thesis
Masters Thesis Civil Engineering 2017
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Govinden, Sumilan. "The effect of montmorillonite clay on the mechanical properties of kenaf reinforced polypropylene composite." Thesis, 2017. https://hdl.handle.net/10539/24131.
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A dissertation submitted to the Faculty of Engineering and the built environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Engineering
Johannesburg, October 2017An investigation was carried out to determine the effect of the addition of clay on the mechanical properties of a Natural Fibre Composite consisting of a polypropylene matrix with kenaf fibre reinforcement. The kenaf fibres were treated using various chemical treatments to improve the strength of the composites manufactured. Four treatments using different 3-mercaptopropyltrimethoxy silane (MPS) concentrations were investigated to determine which treatment resulted in the best mechanical properties. [Abbreviated Abstract. Open document to view full version]
MT 2018
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Khoathane, Moshibudi Caroline. "Natural fibre reinforced polyolefins composites for structural applications." Thesis, 2012. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000602.
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D. Tech. Chemical, Metallurgical and Materials EngineeringAims to develop a thermoplastic matrix-based composite with a view to identifying the most suitable combinations of locally available natural fibres and matrices, which meet some basic requirements (e.g., fire and moisture resistance) for the structural and non-structural materials utilised in the building and construction industries.This general goal is divided into three distinct aims: 1. Examine the chemical surface modification of natural fibres (flax, hemp, pineapple and sisal) using water glass (WG). The study investigates the effect of WG treatment on the mechanical and thermooxidative properties of natural fibres. 2. To produce untreated and WG-treated short sisal/polypropylene (with or without maleic anhydride-grafted-polypropylene) compounds using the injection moulding process. The study also investigates the failure behaviour of the composites produced by the tensile-acoustic emission technique as well as the thermal and water absorption characteristics thereof. 3. To produce untreated and WG-treated nonwoven sisal/polypropylene (with or without maleated polypropylene) composites by using the compression moulding process. The study also investigated the fire resistance characteristics of composite materials.
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Asumani, Oscar. "Characterization of the mechanical and moisture absorption properties of kenaf reinforced polypropylene composites." Thesis, 2014. http://hdl.handle.net/10539/15415.
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Great interest has been generated in the use of natural fibres as environmentally
friendly reinforcing materials in polymeric composites, which do not require high
load bearing capabilities. kenaf fibres extracted from kenaf plants (hibiscus
cannabinus) have been identified as an attractive option due to its production cost
and the ability of the kenaf plants to grow in a variety of climatic conditions.
Polypropylene (PP) has a relatively low production cost, excellent corrosion
resistance, good retention of mechanical properties and less recycling challenges
in comparison to other matrix systems such as thermosets. Given the individual
advantages of kenaf fibre and polypropylene, kenaf reinforced polypropylene
composites (kenaf/PP composites) have considerable commercial interest in the
composite industry. However, limitations arise with respect to the mechanical
performance and to the resistance to moisture absorption when natural fibres are
used.
This study focuses on the improvement of the mechanical properties (e.g. tensile,
flexural, fatigue and impact properties) and the resistance to moisture absorption
of kenaf reinforced polypropylene composites by means of fibre treatments (e.g.
alkali and alkali-silane treatments) and the use of filler materials (e.g.
functionalized multi-wall carbon nanotubes). Kenaf reinforced polypropylene
composites are manufactured by a modified compression moulding using the
film–stacking technique. The crux of this technique is that kenaf mats are
impregnated with polypropylene powder in order achieve a uniform material
distribution and to lower the manufacturing temperature, thereby preventing the
thermal alteration of the composite constituents (e.g. kenaf fibres) and silano
functional groups attached to the multi-wall carbon nanotubes. Fibre treatments
including alkali treatments and alkali followed by silane treatments (alkali-silane)
are considered in order to improve the fibre-matrix interfacial adhesion. The
concentrations of the alkali solutions range from 1% to 8% in intervals of 1% by
mass. Fibre contents ranging from 20% to 35% in interval of 5% by mass are
considered for both kenaf and glass fibre reinforced plates. Functionalized multi-wall carbon nanotubes are used as filler material in order to improve the
mechanical properties of the composite plates. The concentrations of the multiwall
carbon nanotube (MWCNT) range from 0.1% to 1.25%.
Mechanical test and microscopic examination results showed that alkali
treatments improve the mechanical properties of kenaf/PP composites. However,
the improvements due to alkali-silane treatments were found to be more
significant because additional silane treatments substantially enhanced the fibrematrix
interfacial adhesion. Material failures in untreated kenaf/PP composites
and alkali treated kenaf/PP composites were mainly characterized by fibre pullouts,
whereas in alkali-silane treated kenaf/PP composites they were characterised
by fibre breakage. Alkali concentrations of 5% and 6% NaOH are found to the
optimum concentrations for both alkali treatment and alkali-silane treatment.
The use of functionalized MWCNTs as filler material improved furthermore the
mechanical properties of kenaf/PP-MWCNT composites in comparison to those
of kenaf/PP and glass/PP composites. The main contributing factors of the
improvements were found to be the enhancement of the interfacial adhesion
between the nanoparticles and the matrix, and also between the nanoparticles and
kenaf fibres. Material failures in kenaf/PP-MWCNT composites were
characterized by fibre breakage and matrix cracks. The optimum MWCNT
concentrations were found to be 0.5% and 0.75%. 30% fibre contents was found
to be the optimum fibre content for both kenaf/PP and kenaf/PP-MWCNT
composites. Test results showed that the fibre treatments, especially alkali-silane
treatment, improved the resistance to moisture absorption of the composites. Test
results also showed that the manufacturing technique, which enables the
manufacturing of composite plates with layers of different moisture diffusion
resistances, has a significant influence on the resistance of kenaf/PP composites.
The addition of multi-wall carbon nanotubes to the polypropylene matrix did not
alter the moisture absorption resistance of kenaf/PP-MWCNT composites. The
impregnation of kenaf and fibre glass mats with polypropylene powder
significantly lowered the manufacturing temperature
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Wei, Chen-Po, and 陳伯瑋. "A study of polypropylene composites reinforced by the fiber recycling from disposable chopsticks." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/08792840921155273129.
Full textAbstract:
碩士朝陽科技大學
應用化學系碩士班
97
This study adopts the compounding method using a Banbury Mixer to blend polypropylene (PP), methylacetylene-propadiene (MaPP) and natural fibers (bamboo) to obtain the natural fiber-reinforced green PP composites. First of all, the bamboo chopsticks were treated with alkali to remove the surface pectin, hemicellulose and other impurities, and then treated by coupling agent to change its nature chemically. Subsequently, PP was blended with different proportions of these chemically-treated fibers and non-treated fibers, to form the plant fiber-reinforced composites. The materials were then investigated for their morphology (dispersibility and compatibility), mechanical (tensile strength, bending endurance and impact strength) and heat distortion temperature (HDT) properties. An observation under the electronic scanning microscope discovered that among the polymer materials, the fibers modified by coupling agent exhibited better compatibility with polymer matrix than the non-treated fibers. Moreover the heat resistant property of polymer materials also improved after the addition of plant fibers. The HDT test showed that the HDT of pure PP was 80°C. However, after adding 60phr of bamboo fibers, its HDT reached up to 144.8°C with an increase of approximately 81%. In addition, a test with the universal tester has indicates that the addition of natural fibers was capable of increasing the mechanical property of PP. The tensile strength of pristine PP was 31.52Mpa, Whereas the composite material comprising 40phr of bamboo fibers would exhibit strength up to 51.89Mpa with an increase of approximately 66%. With regard to bending endurance, the bending endurance of pristine PP was 45.58Mpa, whereas when the composite material comprising 60phr bamboo fibers would exhibit bending endurance up to 73.9Mpa with an increase of approximately 62.1%. Moreover, the impact strength of pristine PP was 24.5J/m, whereas the composite material comprising 40phr bamboo fibers would exhibit impact strength up to 48.3J/m with an increase of approximately of 97.1%. In general, the addition of plant fibers not only would lower the costs of the materials, but also reduce the consumption of petrochemical plastics that would cause pollution. Moreover, it is also capable of enhancing agricultural development and cutting down agricultural wastes that would damage the environment.
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Tsai, Chou-Yung, and 蔡州永. "A Study on Mechanical and Thermal Properties of Basalt Fiber Reinforced Polypropylene Composites." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/nuvsa5.
Full textAbstract:
碩士國立臺北科技大學
有機高分子研究所
100
Composites are a new material composed from two or more materials with different mechanical and chemical properties. They are normally formed by integrating organic and inorganic materials, taking the advantages of high stress, high hardness and thermal stability of inorganic ones, combined with the virtue of high toughness, the ability for processing of organic ones to produce a united material with characteristics of both. This study was to investigate the tensile properties and damage behavior of basalt staple fiber reinforced thermoplastic polypropylene composites. Various proportions of basalt staple fiber were added to the polypropylene, and the twin-screw mixer was applied for the evenly mixing result. Afterward, tensile specimens were obtained by using the injection molding machine. The decomposition temperature and weight loss rate of basalt staple fiber / polypropylene composite were analyzed by TGA. The variation in melting temperature was analyzed by DSC. A computer servo controlled tensile testing machine was used and the testing method was complied with the standard CNS4396 K6423. The results showed that the tensile elastic modulus increases with the increasing of basalt staple fibers. Also, while the added amount of basalt staple fiber was 12wt%, the proposed composite was with the largest yielding stress. For thermal properties, it was obviously that the inorganic fillers would raise the thermal decomposition temperature that would enhance its thermal stability.
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Chia-Chuan, Chang, and 張家銓. "The Performances and Crystallization Effects of the Particle Size on the Talc Particles Reinforced Polypropylene Composites." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/242zeh.
Full textAbstract:
碩士崑山科技大學
材料工程研究所
107
In this study, PP/Talc composites were fabricated using a twin screw. To estimate the performances of the PP/Talc composites, mechanical properties, heat deflection temperature (HDT), thermomechanical analysis, and isothermal crystallization characterization were conducted. Incorporating talc particles increased the tensile strength, flexural properties, and HDT of the PP matrix, but reduced the elongation at break and notched impact strength. Moreover, the inclusion of talc particles in PP/Talc composites induced heterogeneous nucleation and considerably reduced the crystallization time. Consequently, the time required for processing was also greatly reduced.
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(11201085), Ronald F. Agyei. "INVESTIGATING DAMAGE IN SHORT FIBER REINFORCED COMPOSITES." Thesis, 2021.
Find full textAbstract:
In contrast to traditional steel and aluminum, short fiber reinforced polymer composites (SFRCs) provide promising alternatives in material selection for automotive and aerospace applications due to their potential to decrease weight while maintaining excellent mechanical properties. However, uncertainties about the influence of complex microstructures and defects on mechanical response have prevented widespread adoption of material models for
SFRCs. In order to build confidence in models’ predictions requires deepened insight into the heterogenous damage mechanisms. Therefore, this research takes a micro-mechanics standpoint of assessing the damage behavior of SFRCs, particularly micro-void nucleation at the fiber tips, by passing information of microstructural attributes within neighborhoods of incipient damage and non-damage sites, into a framework that establishes correlations between the microstructural information and damage. To achieve this, in-situ x-ray tomography of the gauge sections of two cylindrical injection molded dog-bone specimens, composed of E-glass fibers in a polypropylene matrix, was conducted while the specimens were monotonically loaded until failure. This was followed by (i) the development of microstructural characterization frameworks for segmenting fiber and porosity features in 3D images, (ii) the development of a digital volume correlation informed damage detection framework that confines search spaces of potential damage sites, and (iii) the use of a Gaussian process classification framework to explore the dependency of micro-void nucleation on neighboring microstructural defects by ranking each of their contributions. Specifically, the analysis considered microstructural metrics related to the closest fiber, the closest pore, and the local stiffness, and the results demonstrated that less stiff resin rich areas were more relevant for micro-void nucleation than clustered fiber tips, T-intersections of fibers, or varying porosity volumes. This analysis provides a ranking of microstructural metrics that induce microvoid nucleation, which can be helpful for modelers to validate their predictions on proclivity of damage initiation in the presence of wide distributions of microstructural features and
manufacturing defects.
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Phiri, Goitseona. "Fracture and failure behaviour of sisal fibre reinforced injection moulded composites." 2011. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000539.
Full text
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"Clinoptilolite-polypropylene composites for the remediation of water systems polluted with heavy metals and phenolic compounds." Thesis, 2012. http://hdl.handle.net/10210/5076.
Full textAbstract:
M.Sc.In this study, natural and modified clinoptilolite (CLI) reinforced polypropylene (PP) composites possessing improved mechanical and adsorptive properties were prepared through melt-mixing. Determination of morphological, structural and thermal properties was achieved by means of different techniques (FTIR, TGA, DSC, electron microscopy and x-ray spectroscopy). Electron microscopy revealed that increasing filler loading beyond 20% leads to agglomeration of clinoptilolite particles reducing their dispersion within the matrix. Thermal studies showed that the reinforced composites had a lower thermal stability than the neat PP polymer, suggesting that the clinoptilolite interfered with polymer chain arrangement and bonding. It also showed that percentage crystallinity increased with increasing filler loading indicating that the filler particles acted as nucleating agents within the polymeric matrix during composite synthesis. Prior to the ion-exchange studies, water sorption behaviour of fabricated composites was evaluated because ion-exchange/adsorption studies were to be performed in aqueous media. It was therefore observed that the hydrophobic polymer, PP attained the property of water sorption mainly due to the porous structure of the composites created by mixing and extrusion and also by the addition of the hydrophilic filler material.
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Parveen, Bushra, Philip D. Caton-Rose, F. Costa, X. Jin, and P. Hine. "Study of injection moulded long glass fibre-reinforced polypropylene and the effect on the fibre length and orientation distribution." 2014. http://hdl.handle.net/10454/10763.
Full textAbstract:
NoLong glass fibre (LGF) composites are extensively used in manufacturing to produce components with enhanced mechanical properties. Long fibres with length 12 to 25mm are added to a thermoplastic matrix. However severe fibre breakage can occur in the injection moulding process resulting in shorter fibre length distribution (FLD). The majority of this breakage occurs due to the melt experiencing extreme shear stress during the preparation and injection stage. Care should be taken to ensure that the longer fibres make it through the injection moulding process without their length being significantly degraded. This study is based on commercial 12 mm long glass-fibre reinforced polypropylene (PP) and short glass fibre Nylon. Due to the semi-flexiable behaviour of long glass fibres, the fibre orientation distribution (FOD) will differ from the orientation distribution of short glass fibre in an injection molded part. In order to investigate the effect the change in fibre length has on the fibre orientation distribution or vice versa, FOD data was measured using the 2D section image analyser. The overall purpose of the research is to show how the orientation distribution chnages in an injection moulded centre gated disc and end gated plaque geometry and to compare this data against fibre orientation predictions obtained from Autodesk Moldflow Simulation Insight.
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Hine, P., Bushra Parveen, D. Brands, and Philip D. Caton-Rose. "Validation of the modified rule of mixtures using a combination of fibre orientation and fibre length measurements." 2014. http://hdl.handle.net/10454/10647.
Full textAbstract:
NoThe goal of this study was to investigate the fibre orientation distribution (FOD), and subsequent mechanical properties, of an injection moulded plate with two different number averaged fibre lengths, termed in this paper medium (1.35 mm) and long (2.40 mm). Fibre orientation measurements (FOD) were made using the 2D elliptical section method and an in-house developed image analyser. The samples were injected from a pin gate located at the centre and top of the plate. Expansion flow on the divergent flow front from this pin gate resulted in a core region with circumferential alignment, while through thickness shear resulted in the usual realignment of fibres in the flow direction either side of the core, termed the shell layers. Two interesting aspects were discovered from these measurements. First, and most importantly, the FOD was found to be independent of the two fibre lengths in this study, and so predominantly controlled by the mould shape and the interaction with the flow front. Second, the fibres in the core region were found to be much closer packed than those in the shell regions. The interaction between the flow front and the mould shape resulted in a range of FOD across the moulded plate, from equal in-plane orientation at the centre of the plate, to highly aligned at the plate edge. This gave a very useful set of samples from which to test out the well known modified rule of mixtures (MROM). Often the fibre orientation distribution cannot be measured directly, but indirectly using the modified rule of mixtures model in reverse. The samples from this moulding (at two different average fibre lengths) gave an excellent opportunity to validate this often used approach. Both the tensile modulus and strength (measured parallel to the injection direction) were found to show a strong correlation with the measured fibre orientation, with a significant increase in both measures between the centre and the edge of both plates. The increased length of the ‘long’ fibre plate was found to give only a small increase in tensile modulus but a much larger increase in tensile strength. The tensile modulus showed a linear dependence with the measured fourth order orientation tensor average, 〈cos4 θ〉, with respect to the injection direction of the plate, as predicted by the modified rule of mixtures. Excellent agreement was found between the measured modulus and the predictions from the modified rule of mixtures, based only on measured quantities (matrix modulus, fibre fraction and average fibre length) for both plates.
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Chang, Ying-Hung, and 莊英鴻. "Study of the Mechanical Properties of Glass Fiber Woven Sheet Reinforced Polypropylene Honeycomb Sandwich Composite." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/69238073650452339867.
Full textAbstract:
碩士桃園創新技術學院
應用科技研究所
104
In this study, we prepared composite materials of sandwich structure with glass fiber woven sheet and polypropylene honeycomb structure by hot press method, then and discussed the mechanical properties of that. In this experiment, four kinds of layer (1, 2, 4 and 6) of glass fiber woven sheet as reinforced material laminated at the top and bottom of four thicknesses( 5, 10, 15 and 20mm) of polypropylene honeycomb structure, respectively. The experimental results show that the optimum value of specific bending strength appears that the 6 layers glass fiber woven sheet reinforced 5mm thickness of polypropylene honeycomb structure and the thickness of polypropylene honeycomb structure was increasing, specific bending strength of composite of sandwich structure was decreased. We also found that maximum value of specific bending modulus appears at the 2 layers glass fiber woven sheet reinforced 5mm thickness of polypropylene honeycomb structure and the layers of glass fiber woven sheet was increasing, the specific bending strength of composite of sandwich structure was decreased. Finally, the maximum value of specific impact strength show that the 6 layers glass fiber woven sheet reinforced 20 mm thickness of polypropylene honeycomb structure and the layers of glass fiber woven sheet was increasing , the specific impact strength of composite of sandwich structure was increased.