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Tang, Eunice Wai Chong. "Preparation and characterization of polypropylene-polypropylene (PP-PP) composites /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20TANG.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 91-95). Also available in electronic version. Access restricted to campus users.
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Kobbe, Ryan Gregory. "Creep behavior of a wood-polypropylene composite." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Summer2005/r%5Fkobbe%5F062905.pdf.
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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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Pehlivan, Hilal Tıhmınlıoğlu Funda. "Preparation and characterization of polypropylene based composite films /." S.l. : s.n.], 2001. http://library.iyte.edu.tr/tezler/master/kimyamuh/T000018.pdf.
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Wang, Kui. "Characterization and modeling of the thermomechanical behavior of polypropylene-based composites : effect of recycling and filler content." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00962217.
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The use of thermoplastic olefins like polypropylene is currently growing in the automotive industry. However, the increase of wastes from end of life vehicles represents a threat to our environment. Mechanical recycling is the most acceptable and ecological method. The purpose of this thesis is to identify the thermomechanical degradation mechanisms of PP-based composites, as a function of fillers content. Recycling was simulated by multiple extrusions. The considered fillers consist of ethylene octene copolymer and talc. The different properties of recycled PP-based composites were studied by a multiphysical approach. A detailed study of high strain rate and temperature sensitivities of recycled PP-based composites is achieved. The micromechanical modeling is used to predict the yield and the elastic behaviors of non-recycled and recycled materials.
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Sjögren, Anders. "Failure behaviour of polypropylene/glass bead composites." Licentiate thesis, Luleå tekniska universitet, 1995. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18681.
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Schildmeyer, Andrew Joseph. "Temperature and time dependent behaviors of a wood-polypropylene composite." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/a%5Fschildmeyer%5F072006.pdf.
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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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Chang, Wei-Ping. "Ultrasound-assisted surface-modification of wood particulates for improved wood/plastic composites." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5824.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains iv, 87 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-86).
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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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Newell, Kathryn J. "Evaluation of stiffness constants of wood fibre polypropylene composite by ultrasonic velocity measurement." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1995. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ51564.pdf.
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Robertson, Christopher G. "Processing of composite fibers based on polypropylene and a thermotropic liquid crystalline polymer." Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/40661.
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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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Zhang, Yan. "Relationship between morphology, crystallization behavior and mechanical properties of polypropylene micro- and nanocomposites /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CENG%202004%20ZHANG.
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Ozturk, Serhat. "Modification Of Calcium Carbonate Surfaces In Natural Gas Plasma For Their Use In Polypropylene Composite Systems." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12608004/index.pdf.
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In this study calcium carbonate (CaCO3) particles are surface modified by using plasma polymerized natural gas and effects of surface modification of CaCO3 filler on mechanical properties of CaCO3-PP composites are investigated. Different combination of plasma factorsRF power, natural gas flow rate, and plasma discharge durations, are investigated. Mechanical properties such as tensile strength and Young&rsquo
s Modulus are measured by tensile testing machine. Storage modulus and loss modulus measurements are done by DMA. Some information about structures generated by natural gas plasma surface modification is obtained by FTIR tests. The tensile fracture surfaces of prepared composites are investigated by using SEM micrographs. It is concluded that, despite some enhancement obtained in the moduli
the technique of natural gas plasma surface modification of CaCO3 particles did not introduce significant improvement in mechanical properties of composite as expected. This result may partially be attributed to selected plasma parameters (i.e., flow rate, RF power, and discharge duration).
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Okubo, H., M. Nagino, H. Kojima, N. Hayakawa, T. Takahashi, and K. Yasuda. "Impulse and ac PD inception characteristics of LN/sub 2//polypropylene laminated paper composite insulation system." IEEE, 2005. http://hdl.handle.net/2237/6830.
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Thevenin, Philippe. "Etude rheologique d'un composite polypropylene/fibres de verre estampe : couplage entre l'orientation et l'ecoulement visqueux anisotrope." Besançon, 1995. http://www.theses.fr/1995BESA2056.
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Ce memoire rapporte une etude experimentale et theorique de la rheologie d'un materiau composite a matrice thermoplastique renforcee de fibres discontinues lors de sa phase de mise en forme par estampage. A l'oppose des materiaux techniques traditionnels, le composite doit au niveau de sa specificite s'adapter aux exigences de conception alors que celle-ci decoule habituellement des proprietes des materiaux constitutifs. En cherchant a realiser simultanement le materiau et le produit, le procede devient indissociable des composants puisque les performances de la structure en dependent etroitement. Un des buts a atteindre est ainsi de disposer les renforts de maniere optimale en fonction des efforts ou des contraintes auxquelles la structure est en mesure d'etre soumise, c'est-a-dire de placer le cout dans les zones les plus sollicitees et non partout ailleurs, comme cela est communement opere en presence de materiaux homogenes et isotropes. Il s'agit en quelque sorte de realiser une anisotropie controlee generatrice de proprietes adequates. Or la fabrication d'un materiau composite a matrice polymere est en general un procede rendu complexe par la nature heterogene de la structure. Et, dans la majeure partie des cas, les proprietes mecaniques et physico-chimiques du materiau objet de la mise en forme presentent un degre d'anisotropie plus ou moins prononce mais dont il serait inopportun de negliger les effets. C'est dans ce contexte que s'inscrit cette etude dont l'objectif est de materialiser le couplage entre l'ecoulement gouverne par une loi de type fluide visqueux anisotrope non-newtonien et l'etat local d'orientation du renfort interagissant et evoluant tout au long de la transformation. Des lois de comportement et d'orientation sont developpees et identifiees sur des ecoulements experimentaux isothermes de type plaque. Puis, la description de l'etat local est integree dans un code de calculs par elements finis permettant de simuler l'ecoulement de maniere globale et de confronter le modele a l'experience. L'interet est d'une part de predire l'evolution de l'anisotropie et ses repercussions sur l'ecoulement, notamment la deformee du front de matiere en presence de bords libres, et d'autre part de pouvoir quantifier l'etat d'orientation final responsable des proprietes mecaniques et physiques de la structure
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ALFARO, EDUARDO de F. "Estudos da utilizacao da cinza de casca de arroz como carga em matriz de polipropileno e do efeito da radiacao ionizante sobre este composito." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9580.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Soroudi, Azadeh. "Melt Spun Electro-Conductive Polymer Composite Fibers." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3590.
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One interesting approach is the development of conductive polymer composite fibers for innovative textile applications such as in sensors, actuators and electrostatic discharge. In this study, conductive polymer composite fibers were prepared using several different blends containing conductive components: a conjugated polymer (polyaniline-complex) and/or carbon nanotubes. Different factors such as processing parameters, the morphology of the initial blends and the final fibers, fiber draw ratio and material selection were studied separately to characterize their effects on the fiber properties. In binary blends of PP/polyaniline-complex, the processing conditions, the matrix viscosity and the fiber draw ratio had substantial effects on the electrical conductivity of the fibers and linearity of resistance-voltage dependence. These factors were associated with each other to create conductive pathways through maintaining an appropriate balance of fibril formation and breakage along the fiber. The blend morphology was defined as the initial size of the dispersed conductive phase (polyaniline-phase), which depended on the melt blending conditions as well as the PP matrix viscosity. Depending on the initial droplet phase size, an optimum draw ratio was necessary to obtain maximum conductivity by promoting fibril formation (sufficient stress) and preventing fibril breakage (no excess stress) to create continuous pathways of conductive phase. Ternary blend fibers of PP/PA6/polyaniline-complex illustrated at least three-phase morphology with matrix/core-shell dispersed phase style. When ternary fibers were compared to binary fibers, the former could combine better mechanical and electrical properties only at a specific draw ratio; this showed that draw ratio was a more determinant factor for the ternary fibers, as both conductivity and tensile strength depended on the formation of fibrils from the core-shell droplets of the PA6/polyaniline-complex through the polypropylene matrix. The achieved maximum conductivity so far was in the range of 10 S/cm to 10 S/cm, which for different samples were observed at different fiber draw ratios depending on the mixing conditions, the matrix viscosity or whether the fiber was a binary or ternary blend. To improve the properties, PP/polyaniline-complex blends were filled with CNTs. The CNTs and the polyaniline-complex both had an increasing effect on the crystallization temperature and the thermal stability of PP. Furthermore, the maximum conductivity was observed in samples containing both CNTs and polyaniline-complex rather than the PP with either one of the fillers. Although increasing the content of CNTs improved the conductivity in PP/CNT fibers, the ease of melt spinning, diameter uniformity and mechanical properties of fibers were adversely affected. Diameter variation of PP/CNT as-spun fibers was shown to be an indication of hidden melt-drawings that had occurred during the fiber extrusion; this could lead to variations in morphology such as increases in the insulating microcracks and the distance between the conductive agglomerates in the drawn parts of the fiber. Variations in morphology result in variations in the electrical conductivity; consequently, the conductivity of such inhomogeneous fiber is no longer its physical property, as this varies with varying size.Thesis to be defended in public on Friday, May 20, 2011 at 10.00 at KC-salen, Kemigården 4, Göteborg, for the degree of Doctor of Philosophy.
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Basson, Nicolaas Christiaan. "The effect of molecular composition on the properties of polyolefin-wood composites." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80222.
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Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Polymer composites, and in particular wood-polymer composites have become commercially and environmentally important materials. Studies in polyolefin-wood composites have mostly focused on polypropylene (PP) and polyethylene (PE). To our knowledge, no study has been undertaken on advancing impact polypropylene copolymer (IPPC)-wood composites as a suitable alternative to using PP and PE. IPPC have proven to be a suitable alternative to PP at low temperatures to improve impact resistance for manufactured polymer products, and could be a great addition to improved properties for wood polymer composites. This study shows that the physical properties of IPPC-wood composites can be markedly improved when compatibilizer(s) are used to improve the distribution of the wood within the matrix, as well as improving the interaction between the wood and the polymer matrix.. The use of different compatibilizers, vi polypropylene-graft-maleic anhydride (PPgMA) and poly(ethylene-co-vinyl alcohol) (EvOH) results in different physical properties. Using simple admixtures of the PPgMA and EvOH in IPPC-wood composites result in a large spread of results, while pre-reacting the PPgMA and EvOH to form a joint compatibilizer gives reproducible results w.r.t the physical testing. A study of the fundamental interactions of the compatibilizer(s) with the molecular components of the IPPCs was undertaken. The IPPCs used were fractionated by preparative temperature rising elution fractionation, and the fractions were mixed with the compatibilizers. To this end, fluorescence microscopy was utilized to study the interaction. The results clearly indicate that the interaction of the PPgMA with the fractions differ from that of the EvOH. These differences can be explained in terms of the chemical composition distribution within the IPPC fractions. Atomic force microscopy (AFM) was used to study adhesive forces between compatibilizer, polymer and cellulose and lignin. Successful coating of AFM tips with PPgMA and EvOH was achieved. Whilst interactions based on chemical force microscopy (CFM) could not be quantified, the AFM results in conjunction with fluorescence spectroscopy provided meaningful insight in the way that compatibilizers interact with both the wood and the impact copolymers used in this study.
AFRIKAANSE OPSOMMING: Polimeer saamgestelde material, en meer spesifiek hout-polimeer saamgestelde material het die afgelope tyd belangrike produkte geword, beide kommersieel en in verband met omgewingvriendelikheid. Navorsing op die gebied van poli(olefien)-hout komposiete het tot op hede meestal gefokus op die grbruik van poli(propileen) (PP) en poli(etileen) (PE). Sover dit on kennis strek is daar nog geen studie gedoen om die gebied van impak polipropileen kopolimere (IPPK)-hout komposiete uit te bou nie. IPPKs is ‘n geskikte alternatief vir PP in veral laetemperatuur aanwendings. Die gebruik van IPPKs as matriks vir die hout komposiete kan ‘n groot staqp vorentoe beteken. Hierdie studie wys dat die fisiese eienskappe van iPPK-hout komposiete merkwaardig verbeter kan word waneer versoeningmateriale gebruik word om die verspreiding van die hout in die polimeermatriks sowel as die interaksie tussen die hout en polimeer te verbeter. Die gebruik van verskillende versoenings material, t.w poli(propileen-ent-maleinsuur anhidried) (PPeMA) en pol(etlieen-ko-viniel alkohol) (EVOH). Deur gebruik te maak van eenvoudige mengsels van PPeMA en EVOH in IPPK-hout composite het ‘n geweldige wye verpreiding van resultate tot gevolg gehad, terwyl ‘n voorafgaande reaksie tussen die PPeMA en die EVOH om ‘n saamgestelde versoeningmateriaal te maak tot gevolg gehad het dat reproduseerbare resultate verkry kon word. ‘n Studie van die fundamentele interaksies van die versoeningsmateriale met die molkulêre komponente van die IPPKs is uitgevoer. Die IPPKs is gefraksioneer deur preparatiewe temperatuur-stygende uitloog frakasionering en die fraksies is gemeng met die versoeningmateriale. Fluoressensie mikroskopie is gebruik om hierdie interaksies te bestudeer. Die resultate dui duidelik daarop dat die interaksie van die PPeMA met die fraksies verskil met die van die EVOH. Die verskille kan verduidelik word aan die hand van die chemiese samestelling verspreiding van die IPPK fraksies. Atoomkrag mikroskopie (AKM) is gebruik om die adhesive-kragte tussen die versoeningmateriale, polimere, sellulose en lignien. AKM tippe is suksesvol bedek met PPeMA en EVOH, onderskeidelik. Alhoewel interaksies gebaseer op chemiese krag mikroskopie (CKM) nie gekwantifiseer kon word nie, lewer hierdie resultate tesame met die fluoressensie spektroskopie unieke insig in die manier wat versoeningmateriale met beide die hout en die polimeer reageer.
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Jadhav, Prakash. "Analytical and experimental investigations of the impact response of grid-stiffened E-glass/polypropylene (PP) composite panels /." Full text available from ProQuest UM Digital Dissertations, 2005. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1276391131&SrchMode=1&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1185301529&clientId=22256.
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Suzuki, Katsuhito. "Study on the continuous production process of microfibrillated cellulose composites." Kyoto University, 2017. http://hdl.handle.net/2433/225321.
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Shiroma, Leandro 1975. "Efeito da composição e tamanho de partículas de resíduos de pinus nas propriedades de compósito de polipropileno." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256913.
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Orientadores: Antônio Ludovico Beraldo, Alcides Lopes LeãoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: Durante o processo de fabricação de paletes de madeira, em uma empresa situada em Limeira-SP, gera-se um volume de resíduo de Pinus sp de aproximadamente 100 toneladas por dia, que atualmente são destinados para queima em indústrias contribuindo para o aquecimento global. O objetivo desta pesquisa foi avaliar as propriedades de um composto de partículas de Pinus sp e de uma matriz de termoplástico de polipropileno (PP). Paralelamente, também se estudou o efeito da composição e do tamanho de partículas de resíduos de Pinus sp nas propriedades de compósitos de polipropileno. Na primeira fase, os compósitos foram processados em uma extrusora de dupla rosca, contendo de 20 a 40% de partícula de madeira e três tamanhos de partículas: 1,2 mm, 0,42 mm e 0,15 mm. Os corpos-de-prova foram injetados de acordo com ASTM e submetidos a ensaios mecânicos de tração, flexão estática e impacto (com e sem entalhe). Os resultados foram submetidos à análise estatística, com o auxílio do software Statgraphics 4.1. No geral, o compósito com a partícula de Pinus sp de 0,15mm foi que apresentou melhor resultado nos ensaios de tração e impacto. Para o ensaio de flexão estática, o compósito à base de Pinus sp com 1,2 mm apresentou o resultado mais adequado. Na segunda fase, o compósito com tamanho de partícula de 0,15 mm foi selecionado e foi novamente processado com as três relações polímero: resíduo adotando-se, no entanto, dois tipos de agente de acoplamento, a saber: polipropileno grafitizado com anidrido maleico (MAPP) e um organosilano, numa razão de 2% em relação à massa de polipropileno, buscando avaliar o desempenho de cada um nas características do compósito, quando submetidos aos ensaios de tração, flexão estática e impacto (com e sem entalhe). Os resultados obtidos foram submetidos à análise estatística com o auxílio de um software buscando-se sua validação, de forma a permitir a escolha da melhor combinação entre os materiais. De forma complementar, avaliou-se o efeito dos tratamentos de superfície aplicados às partículas de Pinus sp, na estabilidade dimensional do compósitos, quando imerso em água. Paralelamente, também se buscou avaliar a modificação na superfície das partículas, por meio da microscopia eletrônica de varredura (MEV), onde se observou a formação de pontos de ancoragem insuficientes na superfície das partículas de Pinus sp quando se utilizou gentes de acoplamento
Abstract: Wood pallets manufacture process at a company at Campinas region generate 100 tons per day of woodflour (Pinus sp), which are currently used for burning in industries of the region contributing to the global warming. The aim of this research was evaluated the effect of formulation and size woodflour (Pinus sp) in properties of polypropylene composite. It was investigated the effect of the wood particle size and polymer: particle ratio in the properties of polypropylene composite. In the first phase, the composite was processed in a twin-screw extruder, containing 20- 40% of wood particles and three particle sizes: 1.2, 0.42 and 0.15 mm. Specimens were molded according to ASTM Standards and submitted to the mechanical tests (tensile, flexural and impact). The results were compared by statistics analysis, with Statgraphics 4.1 software. In general, best results were obtained with composite with size Pinus sp of 0.15mm in the tensile and impact test. To flexural, best results were obtained with composite with size of 1.2mm. In second phase, the composite with particle 0.15mm was processed again with 20- 40wt% and coupling agent, maleic anhydride modified polypropylene (MAPP) and organosilane, added in ratio of 2% of total weight of PP by assessing the performance between them when submitted a tensile, flexural and impact test (notch and unnotcht). The results were compared by statistics analysis, with a software, to validate best combination of materials. The effect of the surface treatments applied to the Pinus sp particle on the dimensional stability of composites when immersed in water. In parallel, also sought to evaluate the change in particle surface, by scanning electron microscopy (SEM), where he observed the formation of insufficient crosslink on the surface of the particles of Pinus sp when using coupling agents
Mestrado
Construções Rurais e Ambiencia
Mestre em Engenharia Agrícola
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Peralta, Marvin Marco Chambi. "Tratamento químico de uma vermiculita visando seu uso em compósitos de polipropileno." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-13102009-161509/.
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Neste trabalho estudou-se o efeito de três diferentes tratamentos químicos utilizando- se soluções aquosas de LiCl, NaCl, e HCl sobre o inchamento, a distribuição de tamanho de partículas e a capacidade de troca catiônica (CTC) de uma vermiculita proveniente da jazida de Paulistana, localizada no Estado do Piauí, visando seu uso em compósitos de matriz polimérica. Para os tratamentos com sais inorgânicos foram utilizadas várias concentrações de LiCl e NaCl a 90°C por 144 horas, permitindo a secagem da solução de tratamento. Para o tratamento ácido foram utilizadas soluções 2M de HCl à temperatura ambiente, utilizando tempos de tratamento de 2 a 10 horas. Após os tratamentos, as amostras foram submetidas a agitação mecânica intensa em dispersor de alta energia de cisalhamento (24000 RPM). Todos os tratamentos empregados resultaram em aumentos nos índices de inchamento e reduçães nos tamanhos de partícula em diferentes graus. Os maiores inchamentos antes da agitação mecânica foram observados nas amostras tratadas com soluções 0,8M de LiCl sem lavagem (4 a 5 vezes a da prova em branco). Após agitação mecânica, os maiores inchamentos foram observados nas amostras tratadas com soluções 2M de HCl por 5 horas (11 vezes a da prova em branco). No entanto, após o processo de secagem não foi possível atingir-se os mesmos valores de inchamento. A diminuição mais importante no tamanho de partícula foi observada nas amostras tratadas com soluções 2M de HCl durante 5 horas, enquanto que as quedas mais significativas nos valores de CTC foram obtidas com as amostras tratadas com soluções 2M de HCl (CTC crescentes com o aumento do tempo de tratamento). Foi analisado o efeito da incorporação de vermiculita tratada acidamente em uma matriz polimérica de polipropileno (PP). A presençaa dessa vermiculita provocou um alto nível de degradação na matriz de PP, com a consequentemente perda de propriedades mecânicas. Esta degradação pode ser atribuída à formação de sítios ácidos nas partículas de vermiculita gerados pelo ataque do HCl, bem como à presença de HCl residual da solução de tratamento.In the present work, the effect of three different chemical treatments using inorganic solutions of LiCl, NaCl, and HCl on the swelling, particle size distribution, and cation exchange capacity (CEC) of a vermiculite clay was studied. The clay is originary from Paulistana mine, located in the State of Piauí, Northeastern Brazil, and the final purpose of the treatment of the clay was its use in polymer-matrix composites. For the inorganic salts treatments, several solutions of NaCl and LiCl at different concentrations were used, at 90°C for 144 hours, allowing the treatment solution to dry out. For the acid treatment, 2M HCl solutions at room temperature were used, using treatment times of 2 to 10 hours. After the treatments, all the samples were subjected to intense mechanical stirring in the high shear energy disperser (24000 RPM). The results showed that all treatments resulted in increases in the rates of swelling and reduction in the mean particle sizes, in different degrees. The largest swelling before mechanical stirring was observed in samples treated with solutions of 0.8M LiCl without washing (4 to 5 times that of the untreated sample). After mechanical desagglomeration, the highest swelling was observed in samples treated with solutions 2M HCl for 5 hours (11 times that of the untreated sample). However, after drying, it was no longer possible to achieve the same values of swelling. The most significant decrease in particle size was observed in samples treated with solutions 2M HCl for 5 hours, whereas the most significant reduction in the CEC values were also obtained with the samples treated with solutions 2M HCl (CEC increasing with the time of treatment). Finally, the effect of the addition of the acid treated vermiculite to a polymeric matrix of polypropylene (PP) was examined. The evaluation of the resultant composite specimens indicated that the presence of vermiculite caused a high level of degradation of the PP matrix, with the consequent loss of mechanical properties. This degradation can be attributed to the formation of acidic sites on the vermiculite particles, generated by the direct attack of HCl, and the presence of residual HCl from the treatment solution.
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Hayakawa, N., T. Kobayashi, M. Hazeyama, T. Takahashi, K. Yasuda, and H. Okubo. "Partial discharge inception characteristics of LN/sub 2//polypropylene laminated paper composite insulation system for high temperature superconducting cables." IEEE, 2005. http://hdl.handle.net/2237/6846.
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Liang, Jiarong. "Cellulose oxalates in biocomposites." Thesis, KTH, Fiber- och polymerteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297506.
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Under de senaste åren, på grund av överanvändningen av icke förnybara resurser har den ekologiska miljön på jorden påverkats allvarligt. I takt med detta ökade oron bland människor om att resurserna skulle ta slut. Därför är det nödvändigt att utveckla och använda mer miljövänliga förnybara resurser. Ett av dessa alternativ är cellulosabaserat material, vilket är ett utmärkt val. Vanligtvis består cellulosabaserat material av ett förstärkande material (cellulosafiber) och en matris (polymer eller metall). Dock bör kompatibiliteten mellan cellulosamaterialet och polymermatrisen ses över, eftersom generellt är kompatibiliteten mellan de låg. I detta projekt studerades olika metoder för att förbättra kompatibiliteten mellan cellulosamaterialet och polymermatrisen. Två cellulosamaterial (mikrokristallin cellulosa (MCC) och cellulosaoxalat (COX)) behandlades med olika modifieringsmetoder för att förbättra kompatibiliteten och gränssnittsinteraktionen mellan materialen. För att modifiera MCC och COX användes bland annat kulmalning, vatten som dispergeringsmedel, förestring av cellulosafibrerna med oljesyra under olika reaktionstider (6, 18, respektive 48 timmar), samt att tillsätta ett kompatibiliseringsmedel, maleinsyraanhydrid-ympad polypropylen (MAPP), i olika halter (1% respektive 2%). För att framställa kompositproverna användes extrudering och formsprutning. Dragprovning genomfördes för att testa de mekaniska egenskaperna hos proverna. Ytterligare karakteriseringsanalyser som utfördes på de olika cellulosapulvren var kontaktvinkeln (CA), svepelektronmikroskopi (SEM), infrarödspektroskopi (FTIR), och röntgendiffraktion (XRD). Resultatet från dragprovningen visade att COX-proverna med 1% MAPP som kompatibilisator gav den högsta draghållfastheten och Youngs modul av alla kompositproverna som producerades i detta exjobb. Användningen av MAPP som kompatibiliseringsmedel visade ett bättre resultat än de andra undersökta metoderna för att förbättra kompatibiliteten mellan den hydrofila ytan på MCC/COX och den hydrofoba ytan på polymermatrisen. Att använda MAPP som kompatibilisator bör prioriteras vid tillverkningen av kompositmaterial.In recent years, with the excessive use of non-renewable resources on the earth, the ecological environment has been seriously affected. At the same time, humans began to worry about running out of resources. Therefore, it is necessary to develop environmentally friendly renewable resources. Cellulose-based material is an excellent choice. Commonly, cellulose-based material consists of reinforcement (cellulose fiber) and matrix (polymer or metal). However, the compatibility between cellulosic material and polymer matrix should be considered. In general, the compatibility between them is poor. In this project, several methods to improve the compatibility between the cellulose material and polymer matrix were studied. Two cellulosic materials (microcrystalline cellulose (MCC) and cellulose oxalate (COX)) were treated with different modification methods to improve the compatibility and interfacial interaction between the cellulosic material and polymer matrix. Ball milling, using water as a dispersing agent, using oleic acid to esterify cellulose fiber for different reaction times (6 h, 18 h, and 48 h), and using different concentrations (1% and 2%) of maleic anhydride grafted polypropylene (MAPP) as compatibilizers were applied to improve the compatibility between cellulose fiber and polymer matrix. To produce the composite specimens, extrusion and injection molding were utilized. Tensile testing was done to test the mechanical properties of the specimens. Contact angle (CA), scanning electron microscope (SEM), Fourier Infrared Spectrometer (FTIR), X-ray diffraction (XRD) were also performed on the various cellulose powders as characterization methods. According to the result of tensile testing, COX samples with 1% MAPP as compatibilizer, showed the highest tensile strength and Young’s modulus of all the composite samples produced in this master thesis. Using MAPP as a compatibilizer shows a better result than using other methods to improve the compatibility between hydrophilic MCC/COX surface and hydrophobic PP matrix. The use of MAPP as a compatibilizer should be prioritized when producing composite materials.
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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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Silva, Celso de Araujo Duarte. "Compósitos de polipropileno reforçados com fibras de sisal para uso na indústria automobilística." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3149/tde-30122014-162204/.
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O polipropileno com carga ou reforço de fibras de sisal (PP Sisal) é um composto desenvolvido para ser aplicado no processo de injeção de peças plásticas automotivas. Compósitos de polipropileno reforçados com cargas minerais (talco) ou fibras de vidro têm sido largamente aplicados nesse segmento. Porém, fibras naturais são uma importante alternativa considerando-se os aspectos de sustentabilidade, reciclabilidade, abundância e baixo custo, se comparadas a fibras de vidro e ao talco industrial. Neste trabalho escolheu-se o sisal como reforço em função dos resultados obtidos em testes de tração, impacto, homogeneidade, resistência a riscos, a não formação de pontas quando fraturado e ao menor peso específico da peça final. Este trabalho conduziu ensaios e testes para comparar o desempenho do novo composto aos compostos atualmente em uso. Resultados mostraram que o PP - sisal apresenta melhor rigidez e maior resistência do que os seus concorrentes, ainda contando com o apelo natural e ecológico do composto. Outro aspecto muito importante neste estudo foi o uso de polipropileno reciclado, o que transformou o resultado final num produto ainda mais ecológico e rentável.Reinforced with sisal fibers, polypropylene (PP - Sisal) is a compound developed to be applied in the injection process of plastic automotive parts. Polypropylene compounds reinforced with mineral fillers (talc) or fiber glass have been widely applied in this segment. However, natural fibers are an important alternative considering the following aspects: sustainability, recyclability, abundant availability and low cost, if compared with fiber glass and mineral fillers. This work chose sisal as reinforcement in function of the results achieved in the tests of traction, impact, homogeneity and scratch resistance. Besides that, no sharp is formed when broken and specific weight is light in the final part. We conducted try-outs and test to compare the performance of the new composition with that of current ones, and results have shown that the PP - sisal presents better rigidity and greater resistance than its competitors, still counting with natural and ecological appeal. Another very important aspect in this study was the use of recycled polypropylene, which made final results more ecological and profitable.
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Selver, Erdem. "Tow level hybridisation for damage tolerant composites." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/tow-level-hybridisation-for-damage-tolerant-composites(8cf53f8c-165f-4e8b-b67f-f8fd34c327e2).html.
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Fibre reinforced composites have higher specific strength and stiffness in comparison to metals. However, composites are susceptible to impact damage resulting in degradation of mechanical properties especially compression strength. Numerous studies have been conducted to improve the impact damage tolerance of composite laminates using modified resin systems, thermoplastic matrices, 3-D fibre architectures and through thickness reinforcement. This work is primarily focussed on incorporating non dissolvable polypropylene fibres (PP) in a thermoset matrix for improving the damage tolerance. Commingling and wrapping techniques have been investigated. PP fibres have been incorporated at the preform stage and hence do not adversely affect the viscosity of the resin during infusion. The healing effect of PP fibres on impact damaged composite laminates when heating is introduced has also been studied. High velocity impact test results showed that using commingled glass/PP fibres increased the total energy absorption of composite laminates by 20% due to the extensive plastic deformation of the PP fibres and through the use of toughening mechanisms in the form of resin cracking and delamination. It has been found that PP fibres provide protection to the glass fibres during low velocity impact loading, so fewer fibre breakages occur which lead to improved residual properties compared with pristine glass laminates. Compression after impact (CAI) tests showed that the residual strength as a percentage of non-impacted strength increased with percentage of PP fibres used. For impact of 20-50J, glass/epoxy laminates retained 32 45% of their compressive strength while laminates with 7%, 13% and 18% PP fibres retained 37 50%, 42-52% and 43-60% of their compressive strength, respectively. It was also observed that glass/PP woven laminates had better compressive strength retention (62 83%) than the glass/PP non-crimp laminates (37-50%). Composite laminates with high-modulus PP fibres (Innegra) exhibited higher residual compression strengths in comparison to laminates with lower modulus PP fibres. For 15-50J impact, glass/Innegra laminates showed residual compression strength of 50 63% in comparison to 39-60%; laminates without thermoplastic fibres exhibited 33 43% residual compression strength. Modulus of thermoplastic fibres appears to be important at higher energy levels. Healing of damaged commingled laminates produced a significant reduction in the damage area and a corresponding increase in CAI strength after heating at 200ºC; CAI strength of healed laminates is about 85% of undamaged samples in comparison to 60% for non-healed samples. A novel micro-wrapping technique, developed in this work, demonstrated significant reduction in damage area (46%) in comparison to the commingling method. Core wrapped laminates had higher residual strength (43-60%) than glass laminates (33-43%). Better PP distribution in core-wrapped composites helped to decrease the PP rich areas and the impact damage did not propagate easily in comparison to commingled composites. However due to the reduction in damage area, impact energy absorption in core wrapped laminates was lower than for commingled.
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ULLOA, MARITZA E. P. "Estudo do efeito da radiação ionizante em compósitos de polipropileno/pó de madeira usando titanato de bário como agente de acoplagem." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11576.
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Made available in DSpace on 2014-10-09T12:53:27Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:09:34Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Alkoles, Omar M. S. "Mechanical behaviour and fracture toughness of unfilled and short fibre filled polypropylene both drawn and undrawn. Experimental investigation the effect of fibre content and draw ratio on the mechanical properties of unfilled and short glass fibre filled polypropylene." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5510.
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The goal of this research is to investigate the combined effects of glass fibre reinforcement and molecular orientation in polypropylene-short glass fibre composites. Specimens have been fabricated using the injection moulding process and drawn using a small die drawing rig. The effects of die drawing on the fibre composites are complex, with the drawing process orienting both the polymer molecules and the glass fibres. This may be accompanied by the creation of voids in the polymer matrix and their destruction in the compressive stress field thus restoring the interfacial contact area between fibre and matrix. Unfilled and short glass fibre filled polypropylene specimens, with fibre content 7% wt, 13%wt, 27%wt, and 55%wt, were injection moulded prior to the die drawing process. An experimental program of die drawing within an oven at elevated temperature was conducted for polypropylene filled to various levels and at different strain rates. The specimens drew to draw ratios in the range ¿=1.41 to ¿=5.6. Mechanical characterization of the test materials has been conducted by examining the tensile stress strain and fracture behaviour under uniaxial conditions. The influence of glass fibre content and drawing conditions (draw ratio) on the fracture toughness and crack propagation was investigated using the double edge notched fracture test. The notch lengths ranged from 1.5 to 2.5 mm for 10 mm wide specimens. The critical stress intensity factor increased as the fibre content increased up to a limiting filler level. The fracture toughness of both unfilled and fibre filled polypropylene were found to be highly dependent on draw ratio. The results were analysed to find out the optimal draw ratio and fibre content that yielded the maximum modulus, strength and fracture toughness. Data showed that, at a given draw ratio, modulus, strength and fracture toughness increased with increasing fibre content to a maximum and then decreased. The optimum material was obtained at a draw ratio of 2.5 and filler loading 13wt%.
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Alkoles, Omar M. "Mechanical behaviour and fracture toughness of unfilled and short fibre filled polypropylene both drawn and undrawn : experimental investigation of the effect of fibre content and draw ratio on the mechanical properties of unfilled and short glass fibre filled polypropylene." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5510.
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The goal of this research is to investigate the combined effects of glass fibre reinforcement and molecular orientation in polypropylene-short glass fibre composites. Specimens have been fabricated using the injection moulding process and drawn using a small die drawing rig. The effects of die drawing on the fibre composites are complex, with the drawing process orienting both the polymer molecules and the glass fibres. This may be accompanied by the creation of voids in the polymer matrix and their destruction in the compressive stress field thus restoring the interfacial contact area between fibre and matrix. Unfilled and short glass fibre filled polypropylene specimens, with fibre content 7% wt, 13%wt, 27%wt, and 55%wt, were injection moulded prior to the die drawing process. An experimental program of die drawing within an oven at elevated temperature was conducted for polypropylene filled to various levels and at different strain rates. The specimens drew to draw ratios in the range γ=1.41 to γ=5.6. Mechanical characterization of the test materials has been conducted by examining the tensile stress strain and fracture behaviour under uniaxial conditions. The influence of glass fibre content and drawing conditions (draw ratio) on the fracture toughness and crack propagation was investigated using the double edge notched fracture test. The notch lengths ranged from 1.5 to 2.5 mm for 10 mm wide specimens. The critical stress intensity factor increased as the fibre content increased up to a limiting filler level. The fracture toughness of both unfilled and fibre filled polypropylene were found to be highly dependent on draw ratio. The results were analysed to find out the optimal draw ratio and fibre content that yielded the maximum modulus, strength and fracture toughness. Data showed that, at a given draw ratio, modulus, strength and fracture toughness increased with increasing fibre content to a maximum and then decreased. The optimum material was obtained at a draw ratio of 2.5 and filler loading 13wt%.
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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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Dostálová, Darina. "Částicové kompozity v konstrukčních detailech obvodových plášťů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390260.
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Due to a European energy concept for reducing energy consumption and also the concept of sustainable development, there is a growing demand for reduced energy consumption during the operation of the building and hence increasing demands on the thermal and mechanical properties of the building envelope. For this reason, it is necessary to look for materials that could meet both thermal and mechanical properties, as well as mechanical resistance and loadability, especially for the application for the foundations of the house, the base of the house and for application to structural details for elimination of the thermal bridges between interior and exterior boundaries. The main motivation for choosing the topic of thesis was to find materials derived from recycled or secondary raw materials that would be suitable for manufacturing composite applicable for structural details in the envelope of the building and for insulating in humid environment. An economic and environmental aspect plays an important role in the choice of material. The main theme of the thesis is the laboratory manufacturing of a composite with a thermoplastic matrix derived from recycled plastic materials and waste foam as a phase. Has been developed a unique Waste-based Particle Polymer Composite (WPPC) made from recycled foam and polypropylene. However, before WPPC can be reliably used by construction designers, physical properties of WPPC must be accurately identified. Therefore, it was designed laboratory manufacturing system and sample testing system, it was studied thermal, mechanical, thermomechanical and moisture absorptivity of WPPC. Application of finished composite material with satisfying thermal insulation properties to structural details to eliminate the thermal bridge, was the next step. These are details of the unloaded, prefabricated balconies, windows, atics, as well as basement constructions and the heel of the central load-bearing wall, the terrain flooring and the staircase wall
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Huczala, Vít. "Vliv fyzikální úpravy sráženého CaCO3 na vlastnosti kompozitu na bázi PP." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217005.
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The diploma thesis deals with study of system of polypropylene and inorganic filler. As filler was used commercially available particulate filler CaCO3 termed NPCC 201. The objective of the study was a surface plasma treatment of filler in order to obtain composite based on polypropylene. Mechanical properties of this composite will show significantly greater value than basic matrix. The filler was treated in dielectric barrier plasma discharge by atmospheric pressure. The characterization of filler was performed before and after plasma treatment by x-ray photoelectron spectroscopy (XPS), electron microscope (SEM) and sedimentation analysis. The distribution of particle size was measured by laser diffraction and by dynamic light scattering. The composite materials with various weight concentration of filler were prepared in POLYMER INSTITUTE BRNO by using the twin-screw extruder and the test specimens were prepared by the injection molding technology. Their mechanical properties was studied by using of short and long-term tests. The uniaxial creep testing in tension was used for study of long-term behavior of composites.
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Alfaro, Eduardo de Faria. "Estudos da utilização da cinza de casca de arroz como carga em matriz de polipropileno e do efeito da radiação ionizante sobre este compósito." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-08082011-105312/.
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Na primeira etapa deste trabalho foi avaliada a potencialidade do uso da cinza de casca de arroz como carga em polipropileno (PP) comparando-a com o talco que é a carga mineral mais utilizada em polímeros. Esta comparação foi feita utilizando os compósitos formados por polipropileno com 20% da cinza de casca de arroz assim como, os formados por polipropileno com 20% de talco, determinando as suas propriedades. Apesar das propriedades do compósito de PP com a carga de 20% de cinza de casca de arroz apresentarem resultados inferiores em relação àqueles quando se utilizou o talco como carga, pode-se dizer que a cinza de casca de arroz pode ser usada como carga para outros usos menos nobres do PP. Desta forma se está dando um destino para esse resíduo que hoje é descartado no meio ambiente contribuindo assim, para a preservação do mesmo, além de reduzir o custo do produto. Este trabalho também teve como objetivo estudar o efeito da radiação ionizante nas propriedades destes compósitos de PP com 20% de cinza de casca de arroz. Utilizou-se o agente de acoplagem, anidrido maleico, para verificar se houve melhora na homogeneização das amostras. Em virtude do PP ser um polímero semicristalino, quando exposto ao processo de irradiação, tem sua morfologia modificada devido aos mecanismos de cisão das cadeias poliméricas. Este fato é atribuído aos mecanismos de cisão das cadeias poliméricas, que está de acordo com a literatura.In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature.
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Righi, Débora Pedroso. "Caracterização do comportamento de compósitos cimentícios de elevada capacidade de deformação com a utilização de fibras de polipropileno e cinza de casca de arroz." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/130106.
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O compósito cimentício de elevada capacidade de deformação é um tipo especial de compósito cimentício de alto desempenho reforçado com fibras, cuja principal característica é a alta ductilidade, devido à capacidade de gerar fissuração múltipla quando em carregamento. Este compósito também é conhecido como Engineered Cementitious Composite (ECC), desenvolvido pelo Pesquisador Professor Victor Li na Universidade de Michigan, nos Estados Unidos. Nos últimos cinco anos, o Laboratório de Ensaios e Modelos Estruturais (LEME) vem desenvolvendo uma linha de pesquisa com o objetivo de adaptar o ECC com materiais locais. Neste intuito, fibras de polipropileno têm sido utilizadas em conjunto com cinza da casca de arroz visando o desenvolvimento de misturas mais viáveis economicamente e mais ambientalmente sustentáveis. Este estudo teve como finalidade avaliar a possibilidade da utilização da cinza de casca de arroz residual (moída em laboratório por 1, 2, 4, 6 e 8 horas) como material pozolânico para substituição parcial de cimento. A caracterização da cinza foi realizada por meio dos ensaios de difração de raio-x, fluorescência de raio-x, perda ao fogo, índice de desempenho, massa especifica e distribuição granulométrica. Este estudo caracterizou compósitos cimentícios de elevada capacidade de deformação contendo 10%, 20% e 30% (em volume) de substituição de cimento por cinza de casca de arroz residual, analisando o comportamento mecânico quanto à tração direta e flexão a quatro pontos. Na busca de um indicativo de durabilidade foram avaliados a absorção e índice de vazios destes compósitos. Além disso, foi realizada a análise da curva de liberação de calor de hidratação para verificar o efeito retardador que a cinza de casca de arroz possa gerar no compósito. E como possível utilização deste compósito como material de reparo, foi analisada a aderência pelo método de cisalhamento oblíquo e pelo método de arrancamento e avaliada a reflexão de fissuras juntamente com a realização de microscopia eletrônica de varredura destes compósitos. Os resultados obtidos mostraram-se satisfatórios para os compósitos com 30% de cinza de casca de arroz moída por 8 e 4 horas, apresentando bons resultados quanto à ductilidade e resistência à propagação de fissuras.The high strain cementitious composite is a special type of fiber reinforced high performance cementitious composite which main characteristic is the high ductility achieved through the ability to generate multiple cracking under loading. This composite is also known as Engineered Cementitious Composites (ECC), which was first developed by Professor Victor Li at the University of Michigan, in the United States. Over the last five years, the Laboratory of Testings and Structural Models (LEME) of UFRGS has developed a research area aiming to adapt ECC with local materials. In this context, polypropylene fibers were used to substitute PVA fibers and rice husk ash was used to partially replace cement, aiming to develop more cost attractive and greener mixtures. This study analyzed the use of non-processed rice husk ash (grinded in laboratory for 1, 2, 4, 6 and 8 hours) as a pozzolanic material by means of x-ray diffraction tests, x-ray fluorescence, fire loss, performance index, specific mass and particle size distribution. This study characterized, in terms of mechanical behavior, the high strain cementitious composites with 10%, 20% and 30% (by volume) of non-processed rice husk ash as cement replacement. The experimental tests were carried out in terms of direct tensile and four points bending tests. Aiming to obtain a first indication of durability, absorption and void rate tests were performed. Other tests were performed to obtain the hydration heat curve aiming to determine a possible retarding effect that the rice husk ash may cause to the composite. Finally, in order to analyze the use of the composite as a reinforcement material, tests were carried out to obtain the bond behavior in terms of oblique shear and pullout methods. The reflection of cracks was also evaluated along with scanning electron microscopy of the composites. The results were satisfactory for composites with 30% of rice husk ashes grinded for 8 and 4 hours, presenting good results in terms of ductility and resistance to crack propagation.
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Gupta, Mohit. "Enhancing the Value of Commodity Polymers Part 1. Structure-Property Relationships in Composite Materials Based on Maleated Polypropylene/Inorganic Phosphate Glasses Part 2. New Value-Added Applications for Polyesters." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1269883793.
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Thesis (Doctor of Philosophy)--Case Western Reserve University, 2010Department of Macromolecular Science and Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Badji, Célia. "Vieillissement de matériaux composites renforcés de fibres naturelles : étude de l’impact sur les propriétés d’aspect et sur les émissions dans l’air intérieur." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3022/document.
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Les biocomposites sont des matériaux renforcés de fibres issues de ressources renouvelables. Ces matériaux sont une solution alternative aux composites renforcés de fibres de verre ou de carbone. En effet, leur légèreté et leurs propriétés mécaniques intéressantes leur confèrent un intérêt grandissant dans les secteurs tels que la construction (terrasse, meubles de jardin) ou l’automobile (panneaux de porte, tableaux de bord). Toutefois, les milieux humides, la température et le rayonnement UV sont des paramètres pouvant compromettre la stabilité physico-chimique des biocomposites. L’objectif principal de cette thèse a été d’évaluer la durabilité des biocomposites sous leurs conditions d’usage principales. Pour cela, ces matériaux ont été exposés pendant une année à l’extérieur (lames de terrasse) et sous vitre pare-brise (tableaux de bord). Les résultats ont montré que, bien que la performance mécanique des biocomposites ait été affectée, celle-ci n’a pas été grandement influencée par le type d’exposition. Par contre, les différences de variations de couleur et de cristallinité différant entre les deux expositions suggèrent des mécanismes de dégradation différents et très dépendants des conditions d’usage.Puisque les biocomposites peuvent être utilisés dans des environnements clos tels que les habitacles d’automobile, ils peuvent être également des sources de polluants dans l’air intérieur. L’étude des émissions de composés organiques volatils (COV) par les biocomposites au cours de leur vieillissement sous vitre pare-brise, a permis de générer des données nécessaires à l’évaluation de l’impact sur la qualité de l’air intérieur de véhicule de ces nouveaux matériaux. Cependant, l’augmentation drastique de la concentration de surface en COV au cours du vieillissement suggère que l’exposition a fortement affecté les biocomposites à cause de la sensibilité des composants structurant les fibres végétales face aux conditions d’exposition.La compréhension des mécanismes de dégradation peut s’effectuer à travers l’interprétation des liens de causalité entre les propriétés mécaniques et de microstructure, les émissions de COV, et l’apparence visuelle. Un traitement statistique par analyse en composantes principales (ACP) a ainsi permis de dégager les relations entre les paramètres quantitatifs.Le vieillissement naturel nécessite souvent une durée d’exposition longue pour apercevoir une dégradation effective des matériaux. De ce fait, le vieillissement accéléré en enceinte de laboratoire est de plus en plus réalisé en industrie permettant un gain de temps. Afin de vérifier la représentativité des mécanismes de dégradation en environnement extérieur par l’enceinte, une étude comparative entre le vieillissement naturel extérieur et un vieillissement accéléré en enceinte a été menéeBiocomposites are fiber-reinforced materials from renewable resources. These materials are an alternative to fiberglass or carbon reinforced composites. Indeed, their lightweight and interesting mechanical properties give them a growing interest in sectors such as building (decking, garden furniture) or automobile (door panels, dashboards). However, humidity, temperature and UV radiation are parameters that can compromise the physicochemical stability of biocomposites.The main objective of this thesis is to assess the biocomposites durability in their main conditions of use. For this purpose, these materials have been exposed for one year outdoors (deck boards) and under windshield glass (dashboards). The results showed that the mechanical performance of biocomposites was affected and greatly influenced by the type of exposure. On the other hand, the differences in color and crystallinity variations that differ between the two exposures suggest different degradation mechanisms that are very dependent on the conditions of use.Since biocomposites can be used in environments such as the passenger cabin, they can also be sources of pollutants in indoor air. The study of emissions of volatile organic compounds (VOCs) by biocomposites during their ageing under windshield glass allowed generating data necessary for the evaluation of the impact on the car indoor air quality of these new materials. However, the drastic increase of VOCs surface concentration during exposure suggests that weathering strongly affected biocomposites due to the sensitivity of the structural components of plant fibers to exposure conditions.Understanding of the degradation mechanisms can be carried out through the interpretation of the causal links between mechanical and microstructural properties, VOC emissions and visual appearance. Statistical treatment by Principal Component Analysis (PCA) revealed the links and relationships existing between the quantitative parameters.Natural weathering often requires long time of exposure for an efficient perception of the materials degradation. Thus, accelerated ageing in laboratory is more and more carried out in industry for time saving. In order to verify the representativeness of the degradation mechanisms occurring during exterior weathering by weathering chambers, a comparative study between the exterior aging and the artificial aging was carried out
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Fichtová, Zlata. "Chování cementových kompozitních materiálů s vláknovou výztuží při působení vysokých teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225882.
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This master’s thesis studies the influence of dispersed reinforcement on the behaviour of cement composites at thermal loading. In the theoretical part of the research was performed knowledge of the behaviour of concrete at high temperatures. The paper describes the on-going happening in the individual components of concrete and benefits of using dispersed reinforcement. In the practical part were designed concrete mixtures with different types and quantities of fibers. The object of the research was to determine how different types and amounts of fibers affect the physical - mechanical properties of concrete and their suitability for use in high temperatures.
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Işık, Kıvanç Tanoğlu Metin. "Layered silicate/polypropylene nanocomposites/." [s.l.]: [s.n.], 2006. http://library.iyte.edu.tr/tezler/master/makinamuh/T000532.pdf.
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Metin, Dildare Tıhmınlıoğlu Funda. "Interfacial enhancement of polypropylene-zeolite composites/." [s.l.]: [s.n.], 2002. http://library.iyte.edu.tr/tezler/master/kimyamuh/T000132.pdf.
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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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Wilks, C. E. "Processing techologies for woven glass/polypropylene composites." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520625.
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Volke, Sebastian. "Modifizierung der Werkstoffeigenschaften von Polypropylen-Kompositen durch eine Hochtemperatur-Elektronenbehandlung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-65355.
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Polypropylene (PP) is a common thermoplastic and frequently adapted permanently with increasing requirements by adding fillers as well as reinforcing materials.
Because of incompatibility of non-polar PP and polar inorganic filler, resulting composites are brittle which has a detrimental effect on the desired properties. Improvements in mechanical properties can be reached by compatibilization, creating of chemical couplings between phases and by increasing of inhomogeneity. Thus, maleic anhydride grafted PP is used as well as reactive processing of PP in presence of peroxide radical initiators. The temperature dependence of peroxide decay as well as the dependence of radical generation rate on time are two disadvantages of peroxide induced reactive processing.
Modification of polymers with high energy electron treatment is also well known and used to form parts (after) molding as well as raw materials (pellets, powders, fibers) in solid state and at room temperature. The spatially and temporally precise input of energy is used to produce desired material properties on radical-induced chemical reactions.
Coupling of high energy electron modification of polymers and melt mixing offers a new possibility of reactive processing. In this case, radical generation is independent of temperature, can be easily controlled by beam current and kept constant over time. Absence of any crystallinity, high reaction rates as well as intensive macromolecular mobility and intensive mixing are reasons to expect novel structures and properties.
Electron beam induced reactive processing is a novel technique where chemical reactions are induced by spatial and temporal precise energy input via high energy electrons under dynamic conditions of melt mixing. This method gives the possibility to increase surface energy of polypropylene (PP) effectively as well as to generate chemical couplings between filler and PP. The process was applied to a proved system consisting of PP (38 wt%), magnesium hydroxide (MH) (60 wt%), triallyl cyanurate (TAC) (2 wt%). This composite system was successful tested in peroxide induced conventional reactive processing. Absorbed dose imparted per rotation of rotors is a new parameter controlling mechanical properties of polymer composites. Improved properties were found in tensile strength (150 %), elongation at break (175 %), and impact strength (175 %). It can be shown that chemical couplings are generated during electron induced reactive processing in comparison to only compatibilized material.
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Jafelice, Domingos Antônio. "Caracterização de compósitos de polipropileno reciclado e fibra de coco." Universidade Presbiteriana Mackenzie, 2013. http://tede.mackenzie.br/jspui/handle/tede/1334.
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Previous issue date: 2013-06-21Despite their many advantages for use in applications such as packaging, garbage bags, personal items, automotive components, appliance, marine, aviation, among others, plastics have a disadvantage at the time of disposal: harm the environment. For this reason, the recycling of plastic has been used frequently by their economic, social and ecological viability. To optimize the properties of plastics often recycled, natural or synthetic fibers are blended to the materials forming the composites. The polymeric composite materials are increasingly used in various applications for their outstanding mechanical, physical and chemical properties. In this study, we characterized the mechanical and morphological properties of recycled polypropylene with coconut fiber. Compounds were obtained by means of mechanical processing, with concentrations of 25%, 20%, 15% and 10% of fibrous reinforcement with and without addition of coupling agent (functionalized polypropylene with maleic anidride). The results showed that the addition of coconut fiber to recycled polypropylene, in the studied concentrations, causes an increase in thermal and mechanical properties such as tensile strength and impact, and a decrease in hardness, and there was almost no change in processing conditions (Melt Index).
Os plásticos, apesar de suas inúmeras vantagens para aplicações como embalagens, sacos de lixo, objetos de uso pessoal, peças utilizadas nas indústrias automobilística, de eletrodomésticos, naval, aeronáutica, entre outras, apresentam uma desvantagem no momento do descarte: nocividade ao meio ambiente. Por esse motivo, a reciclagem de plásticos vem sendo utilizada com freqüência por sua viabilidade econômica, social e ecológica. Devido ao reprocessamento, os plásticos perdem propriedades a cada ciclo de reciclagem. Para otimizar as propriedades dos plásticos, muitas vezes reciclados, são misturadas fibras naturais ou sintéticas a esses materiais, formando os compósitos. Os compósitos poliméricos são cada vez mais usados nas mais variadas aplicações por suas extraordinárias propriedades físico-mecânicas. Neste trabalho, foram caracterizadas as propriedades mecânicas e morfológicas do polipropileno reciclado com fibra de coco. Foram obtidos compósitos de polipropileno, por meio de processamento mecânico, com concentrações de 10, 15, 20 e 25% em massa de fibra de coco, com e sem adição de agente de acoplagem (polipropileno funcionalizado com anidrido maleico) nas concentrações de 0, 2 e 3% em massa. Os resultados mostraram que a adição da fibra de coco ao polipropileno reciclado, nas concentrações estudadas provoca um acréscimo nas propriedades térmicas e mecânicas, como a resistência à tração e impacto e um decréscimo na dureza, sendo que praticamente não houve alteração nas condições de processamento (índice de fluidez).
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Ponçot, Marc. "Comportements thermomécaniques de polymères chargés selon différents chemins de déformation et traitements thermiques." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL064N/document.
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Le centre de recherche ArcelorMittal de Montataire développent de nouvelles solutions acier innovantes associant métal et polymère. Pour les ailes de voiture, le composite retenu est un matériau multicouche composé d’une lame d’acier sur laquelle est déposé un film mince de polypropylène choc chargé avec des particules minérales par l’intermédiaire d’une fine couche de polypropylène fonctionnalisé par le greffage d’anhydride maléique. Afin de prévoir et de connaitre le comportement de la partie organique du matériau lors de sa mise en forme par emboutissage et à posteriori de prédire l’état de ses propriétés mécaniques lors de son utilisation, la détermination des lois de comportement mécanique vrai et intrinsèque sur le modèle de la loi G’sell et Jonas est nécessaire. Ces lois sont définies selon trois chemins de déformation : la traction uniaxiale, le cisaillement simple et la traction plane. Les micromécanismes de déformation de la microstructure semi-cristalline des différentes formulations des matériaux selon leur mode de sollicitation mécanique ont été étudiés. Les résultats obtenus Post Mortem et In Situ ont permis la description qualitative et quantitative des évolutions des principales modifications microstructurales. Ces dernières diffèrent avec l’ajout de charges minérales. Deux nouvelles méthodes, la Tomographie X et la spectroscopie Raman permettent la détermination de la déformation volumique dans le cas de matériau de géométrie fine (300 µm). Le retrait lors d’un cycle thermique est étudié. Les influences du chauffage, de la formulation et de la microstructure (orientation des chaînes macromoléculaires et endommagement volumique) sont décritesThe ArcelorMittal research centre of Montataire elaborates innovative steel / polymer products. In the case of automotive fenders, the composite is a multilayered material. A thin impact polypropylene film is laminated on steel using a thin layer of a functionalized polypropylene. Mineral particles are added to improve stiffness. In order to predict and understand the behaviour of the organic layer all along its production process and finally to be able to characterize the state of its mechanical properties in use, the determination of the true and intrinsic mechanical behaviour laws according to the G’sell and Jonas model is necessary. These laws are obtained for three different mechanical paths: uniaxial tensile, simple shear and plane tensile. The deformation micromechanisms of the impact polypropylene semi-crystalline microstructure which depend on the materials formulations and on the mechanical path used are studied. Post Mortem and In Situ results give qualitative and quantitative description of the main microstructural modifications. Two new methods, X Tomography and Raman spectroscopy allow the quantification of the volume deformation which is developed during tensile tests. They are mainly available for very thin samples. X radiography and VideoTraction™ are not suitable anymore for this kind of geometry. Finally, the thermo-mechanical phenomenon of shrinkage which occurs during thermal treatment above the material melting point is analysed. Influences of the heating conditions, of the material formulations and of the material microstructure are described. Special overviews are done on the macromolecular chains orientation and on the volume damage influences
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Vallejos, María Evangelina. "Aprovechamiento integral del Cannabis sativa como material de refuerzo/carga del polipropileno." Doctoral thesis, Universitat de Girona, 2006. http://hdl.handle.net/10803/7793.
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En este trabajo se ha estudiado el potencial tanto los filamentos de cáñamo como de la cañamiza como refuerzo/carga del polipropileno. La modificación de estos materiales se realiza para lograr una mayor compatibilidad con la matriz polimérica. Se evaluaron las propiedades mecánicas de las resistencias a tracción e impacto, de los materiales compuestos reforzados tanto de filamento como de cañamiza. Los filamentos de cáñamo poseen suficiente capacidad de refuerzo en los materiales compuestos basado en polipropileno debido a sus propiedades intrínsecas, siendo una buena alternativa como material de refuerzo. Así, la adición de MAPP (polipropileno modificado con anhídrido maleico) conduce a materiales compuestos con unas resistencias a tracción de hasta el 70% de las que se obtienen con compuestos de PP reforzados con fibra de vidrio. Mientras que la cañamiza ha actuado como una carga en la matriz, incrementado significativamente la rigidez de los materiales compuestos.In this work, the potential of hemp strands as well as hemp straw, to be used as reinforcement/filler of polyprppylene has been studied. The modification of these materials ha been carried out to obtain a greater compatibility with the polymer matrix. The mechanical properties of the obtained materials were evaluated under tensile, flexural and impact stresses. The hemp strands showed a sufficient capacity of reinforcement in the polypropylene-based composite due to their intrinsic properties, being a good alternative like reinforcement agent. Thus, the addition of MAPP (polypropylene modified with maleic anhydride) leaded to composites with a value of ultimate tensile strength that achieved 70% of the value of materials formulated with PP and fibreglass. In the particular case of the addition of hemp straw, this component acted as a filler of the polymer matrix, increasing the rigidity of the composite but with a limited influence in the ultimate tensile strength.
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Premphet, Kalyanee. "Structure-property characterisation of ternary phase polypropylene composites." Thesis, Brunel University, 1995. http://bura.brunel.ac.uk/handle/2438/7276.
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An investigation to study factors controlling the structure and properties of binary- and ternary-phase polypropylene (PP) composites containing ethylene-propylene rubber (EPR) and glass beads has been carried out. The composite structure was evaluated using various techniques including SEM, DSC, XRD and DMA. While the mechanical tests included tensile and impact measurements at ambient temperature, and a fracture toughness test based on the J-integral method carried out at -20 oC. EPR and glass beads were found to influence the structure and properties of polypropylene in different ways. Incorporation of EPR into polypropylene results in an improvement in impact strength and toughness, accompanied by a decrease in tensile strength and modulus. The opposite was found for composites containing glass beads. Polypropylene composites with balanced mechanical properties were achieved by physical blending of this polymer with both EPR and glass beads. The effect of composite structure, composition and processing variables on the properties of the ternary systems were analysed. A study of their morphology has shown that two kinds of phase structure can be formed, either a separate dispersion of the phases, or encapsulation of the filler by rubber. Factors controlling these structures are believed to be due mainly to the surface characteristics of the components. Modification of EPR by maleic-anhydride grafting results in composites with rubber encapsulation of the filler, with FTIR revealing a reaction between these phases. Composites containing unmodified EPR, on the other hand, show separate dispersion of the components. The former composites, with good adhesion at the rubber and filler interface, have noticeably higher impact strength and fracture toughness at and below ambient temperatures, while the latter variant is characterised by higher tensile strength and modulus, accompanied by a lower impact strength. Improvements in impact strength of the composites was also achieved by promoting adhesion between the polymer and filler interface using surfacecoated glass beads, or by increasing the number of rubber particles adhering to the glass bead surfaces using a two-step mixing technique. Results of the present study have thus shown that mechanical properties of ternary phase polypropylene composites can be adjusted, to a certain extent, by controlling their morphologies through the use of suitable functionalised materials and also by using an appropriate compounding methodology.
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Toke, Jeff M. "Investigating interfacial phenomena in polypropylene/glass fiber composites." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/10023.
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