Extrusion and mechanical properties of highly filled cellulose fibre–polypropylene composites

Bengtsson, Magnus; Baillif, Marie Le; Oksman, Kristiina

doi:10.1016/j.compositesa.2007.03.004

Cited by 158 publications

(146 citation statements)

References 24 publications

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“…As condições de processamento escolhidas são muito importantes na qualidade da dispersão e na prevenção da aglomeração das fibras na matriz polimérica, especialmente nos compósitos com carga lignocelulósica, pois essas podem ser empregadas em altas concentrações, pelo fato de apresentarem baixo caráter abrasivo [21] . Fibras curtas também reduzem os problemas relacionados à dificuldade de alimentação e à ação cisalhante do equipamento, pois quanto menor é o comprimento das fibras, menores são os efeitos da redução de tamanho causados por sua quebra durante o processamento [22,23] .…”

Section: Processamento E Moldagemunclassified

Extrusão de compósitos de PP com fibras curtas de coco: efeito da temperatura e agentes de acoplamento

et al. 2010

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que os dois agentes de acoplamento melhoraram o módulo elástico, a tensão máxima e a resistência à absorção de água quando os materiais foram processados utilizando-se um perfil de temperaturas mais elevadas. A morfologia dos compósitos também ficou mais homogênea na presença dos agentes de acoplamento, especialmente naqueles processados na temperatura mais alta. Esses resultados indicam que a temperatura é uma variável fundamental no estabelecimento das interações envolvendo os processos de compatibilização. Palavras-chave: Compósitos, fibras naturais, agentes de acoplamento, extrusão, absorção de água. Extrusion of PP Composites with Short Coir Fibers: Effect of Temperature and Coupling AgentsAbstract: PP composites filled with coir short fibers were prepared in an extruder using two temperature profiles. The objective was to evaluate the compatibilizing effect of PP modified with vinylsilane and with maleic anhydride. Both coupling agents improved elastic modulus, tensile strength and water absorption resistance when the materials were processed at the highest temperature profile. The composite morphology was more homogeneous in the presence of the coupling agents, mainly in the composites processed at the highest temperatures. These results indicate that temperature is a key variable for the establishment of the interactions involved in the coupling processes. Keywords: Composites, natural fibers, coupling agent, extrusion, silane. IntroduçãoO desenvolvimento sustentável, a redução da demanda por materiais de origem fóssil e a redução da produção de resíduos são fatores que se relacionam entre si e que, bem conduzidos, podem resultar em benefícios importantes para a vida humana [1] . Nesse contexto o Brasil, na qualidade de concentrador de uma das mais ricas biodiversidades do planeta, tem um papel fundamental [2] . O crescente interesse no uso de fibras naturais na preparação de compósitos poliméricos constitui uma alternativa de obtenção de novos e interessantes materiais com menor impacto ambiental porque permite substituir parte dos polímeros obtidos a partir de material fóssil por fibras de origem agrícola, de caráter renovável e biodegradável. Além disso, muitas fibras e cargas vegetais constituem resíduos da atividade agrícola e seu aproveitamento, além de lhes prover um destino final racionalizado, pode reduzir os custos de preparação do produto final. Uma das principais aplicações dos compósitos poliméricos com fibras vegetais tem sido na indústria automobilística [3,4] , porém seu uso também tem se mostrado promissor na construção civil e na produção de artefatos de uso geral, tais como solados de calçados, pentes, utensílios domésticos e outros.O Brasil é um país que se destaca na produção de muitas fibras, tais como sisal, rami, algodão, coco e juta, porém diversas outras espécies são encontradas e cultivadas no país [5,6] . No Brasil, as fibras obtidas da casca do coco são materiais lignocelulósicos de baixo custo, que não encontram aplicação em fins alimentícios, por isso representam uma intere...

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Section: Processamento E Moldagemunclassified

Extrusão de compósitos de PP com fibras curtas de coco: efeito da temperatura e agentes de acoplamento

et al. 2010

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“…The thermal stability of cellulose was found to depend mainly on its crystallinity 11,12 . Thus, cellulose crystallinity and hydrogen bond between cellulose chains play an important role in the mechanical and thermal properties of composite materials reinforced with cellulose fibers 1,13 . Several techniques as X-ray diffraction and FTIR spectroscopy were used to evaluate the wood and cellulose crystallinity 5,7,8,9,10,12 .…”

Section: Introductionmentioning

confidence: 99%

“…Cellulose fibers are extensively used to reinforce polymeric composite materials [1][2][3][4] . The considerable interest in these fibers is due to their biodegradability, renewability, low density and mechanical properties comparable to those inorganic fibers 5 .…”

Section: Introductionmentioning

confidence: 99%

Materials produced from plant biomass: part II: evaluation of crystallinity and degradation kinetics of cellulose

et al. 2012

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In this study Eucalyptus grandis (CEG) and Pinus taeda (CPT) cellulose fibers obtained from kraft and sulfite pulping process, respectively, were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetry (TGA). The degradation kinetic parameters were determined by TGA using Coats and Redfern method. FTIR results showed that CPT presented a more ordered structure with higher crystallinity than CEG. Thermogravimetric results showed that CPT had a higher thermal stability than CEG. The kinetic results revel that for CEG the degradation mechanism occurs mainly by random nucleation, although phase boundary controlled reactions also occurs while for CPT the degradation process is more related with phase boundary controlled reactions. Results demonstrated that differences between thermal stability and degradation mechanisms might be associated with differences in the cellulose crystalline structure probably caused by different pulping processes used for obtaining the cellulose fibers.

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“…These composites are mostly produced by thermoforming; however, they can be also produced by continuous large scale processes, like extrusion [4,5] , and can be molded into detailed parts, with good surface finishing, by injection molding. In contrast to glass fibers, vegetal fibers are: less dense, obtained from renewable sources and biodegradable.…”

Section: Introductionmentioning

confidence: 99%

“…For polyolefins, polymers grafted with maleic anhydride are commonly used as coupling agent [12] . In this case the agent is mainly localized at the polymer/fiber interface, with the polymeric component of the coupling agent interacting with the hydrophobic polymer matrix and the maleic anhydride interacting with the hydrophilic fibers [9,5] , promoting adhesion between the two phases [13] .…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties, morphology and thermal degradation of a biocomposite of polypropylene and curaua fibers: coupling agent effect.

et al. 2013

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Biocomposites of polymers with vegetal fibers have a broad spectrum of applications due to their high specific properties in comparison to their counterparts made with fiberglass. Polypropylene, PP, composites with curaua fiber compatibilized with different concentrations of maleic anhydride grafted polypropylene, PP-g-MA, were characterized according to their mechanical properties, morphologies and thermal stabilities in oxidative and inert atmospheres. The composites were prepared by single screw extrusion and injection molded specimens were used for testing. The composite with 20 wt % of curaua fiber with and without compatibilizer presented improved mechanical properties compared to pure PP. The use of PP-g-MA as a compatibilizer significantly increased fiber/matrix adhesion, however, the mechanical properties were only slightly improved in comparison with composites without compatibilizer. We observed an improvement in thermal stability of the composites, compared to that expected from the weighted average of the individual components, both under inert and oxidative atmospheres. Furthermore, the thermal stability improved under inert atmosphere as a function of the concentration of compatibilizer. In this situation, indeed, there was a different shift of the weight loss processes owing to the presence of the compatibilizer.

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Extrusion and mechanical properties of highly filled cellulose fibre–polypropylene composites

Cited by 158 publications

References 24 publications

Extrusão de compósitos de PP com fibras curtas de coco: efeito da temperatura e agentes de acoplamento

Extrusão de compósitos de PP com fibras curtas de coco: efeito da temperatura e agentes de acoplamento

Materials produced from plant biomass: part II: evaluation of crystallinity and degradation kinetics of cellulose

Mechanical properties, morphology and thermal degradation of a biocomposite of polypropylene and curaua fibers: coupling agent effect.

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