Thermoset matrix reinforced with sisal fibers: Effect of the cure cycle on the properties of the biobased composite

Megiatto, Jackson D.; Silva, Cristina G.; Ramires, Elaine C.; Frollini, Elisabete

doi:10.1016/j.polymertesting.2009.07.001

Cited by 61 publications

(36 citation statements)

References 28 publications

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“…A incorporação de fibras de sisal a plásticos tem sido reportada por vários pesquisadores, que investigaram a viabilidade do desenvolvimento de compósitos poliméricos de baixo custo reforçados por fibras de sisal por meio da avaliação das propriedades mecânicas, reológicas, elétricas e viscoelásticas desses compósitos [4][5][6]9,[24][25][26][27] .…”

Section: Compósitosunclassified

“…Alguns pesquisadores [6,22,23,[28][29][30][31][32] avaliaram as propriedades mecânica de impacto de compósitos poliméricos. Em especial, o elevado trabalho de fratura obtido para os compósitos reforçados por sisal, apesar de estas fibras apresentarem problemas de adesividade, …”

Section: Compósitosunclassified

“…No entanto, há vários trabalhos na literatura que avaliam o reforço de fibras celulósicas em diversos tipos de matrizes poliméricas com objetivo de melhorar o desempenho mecânico e/ou compensarem possíveis degradações de compósitos poliméricos [3][4][5][6][7][8][9][10] . As fibras vegetais são abundantes, não-tóxicas, de baixo custo, de baixa densidade, não são abrasivas e, portanto, não desgastam os equipamentos, assim como provêm de fontes renováveis.…”

Section: Introductionunclassified

“…Fernandes e Domingues analisaram-se as propriedades mecânicas de misturas de PP virgem e reciclado, em três porcentagens diferentes, por meio de ensaios de tração axial e de impacto Charpy. Esses pesquisadores concluiram que porcentagens de reciclado acima de 30% causam deterioração das propriedades mecânicas do produto [2] .No entanto, há vários trabalhos na literatura que avaliam o reforço de fibras celulósicas em diversos tipos de matrizes poliméricas com objetivo de melhorar o desempenho mecânico e/ou compensarem possíveis degradações de compósitos poliméricos [3][4][5][6][7][8][9][10] . As fibras vegetais são abundantes, não-tóxicas, de baixo custo, de baixa densidade, não são abrasivas e, portanto, não desgastam os equipamentos, assim como provêm de fontes renováveis.…”

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Resíduos de sisal como reforço em compósitos de polipropileno virgem e reciclado

et al. 2011

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Resumo:Foram estudadas as propriedades térmicas e mecânicas de compósitos de polipropileno, virgem e reciclado, reforçados com 30% em massa de fibras residuais de sisal, assim como o perfil de processamento e a morfologia da matriz polimérica. Para tanto, foram determinadas a resistência à tração, o módulo de Young, alongamento na ruptura, e energia de impacto. As amostras também foram caracterizadas por MEV, DMTA e TG. Para ambos os compósitos de polipropileno, virgem e reciclado, com a adição das fibras, o alongamento na ruptura mostrou uma queda significativa, enquanto que a resistência à tração não sofreu grandes variações. Houve um aumento significativo nos valores de tração na ruptura e de energia de impacto com a adição das fibras de sisal na matriz de polipropileno. As análises térmicas mostraram ligações secundárias, como as ligações polares, entre as fibras e a matriz, concordando com o comportamento mecânico dos compósitos. Constatou-se que a temperatura de transição vítrea não variou após a adição da fibra. Palavras-chave: Sub-produto do sisal, extrusão, compatibilidade, propriedades mecânicas, propriedades térmicas. Virgin and Recycled Polypropylene Composites Reinforced with Sisal By-ProductAbstract: The mechanical and thermal properties of virgin and recycled polypropylene composites reinforced with 30% by mass of residual sisal fibers were studied, in addition to an analysis of the extrusion process and morphology of the polymeric matrix. Tensile strength, Young's modulus, elongation at break, and impact energy were determined. The samples were also characterized by SEM, DMTA and TG analyses. Elongation at break of the composites presented a significant decrease, while the tensile strength was not affected significantly by addition of sisal fibers. A significant increase was observed in the tension of rupture and in the impact energy of the composite reinforced with sisal fiber. The thermal analyses indicated secondary interactions, such as polar interactions, between the fibers and the matrix, consistent with the mechanical behavior of the composites. The glass transition temperature has not changed after fiber addition. Keywords: Sisal by-product, extrusion, compatibility, mechanical properties, thermal properties. IntroduçãoO polietileno de baixa e alta densidade e polipropileno representam 45% da produção de plástico no mundo [1] . Particularmente, o polipropileno (PP) virgem é amplamente explorado, mas o aumento do custo das resinas plásticas, pressionado pelas constantes flutuações do preço do petróleo no mercado internacional, tem estimulado as pesquisas em reciclagem deste polímero. Normalmente, o preço do plástico reciclado é 40% mais baixo do que o da resina virgem [2] . Fernandes e Domingues analisaram-se as propriedades mecânicas de misturas de PP virgem e reciclado, em três porcentagens diferentes, por meio de ensaios de tração axial e de impacto Charpy. Esses pesquisadores concluiram que porcentagens de reciclado acima de 30% causam deterioração das propriedades mecânicas do produt...

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Section: Compósitosunclassified

Section: Introductionunclassified

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Resíduos de sisal como reforço em compósitos de polipropileno virgem e reciclado

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“…However, the use of natural fibers as reinforcement agent, particularly in hydrophobic polymeric matrices, has some drawbacks such as poor adhesion in the fiber/matrix interfacial region. This is because the natural fibers are highly polar due to the high polysaccharide content (hemicelluloses and cellulose), making the lignocellulosic fibers to also be highly hydrophilic [5]. Moreover, the large moisture sorption of natural fibers adversely affects adhesion with hydrophobic matrices that may cause material degradation and loss of strength [6].…”

Section: Introductionmentioning

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Effect of Chemical Treatment on Mechanical and Water-Sorption Properties Coconut Fiber-Unsaturated Polyester from Recycled PET

Abdullah

Ahmad

2012

ISRN Materials Science

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Coconut fibers were used as reinforcement for unsaturated polyester resin from recycled PET that has been prepared using glycolysis and polyesterification reaction. Various concentrations of alkali, silane, and silane on alkalized fiber were applied and the optimum concentration of treatments was determined. Morphological and mechanical properties of the composite have also been investigated to study the effect of fiber surface treatment. The influence of water uptake on the sorption characteristics of composites was studied via immersion in distilled water at room temperature. Surface treatment of coconut fiber caused a significant increase in the tensile properties with the optimum treatment of 0.5% silane on the 5% alkalized coconut fiber/polyester composites. For water absorption study, it was observed that the treated fiber composites showed lower water absorption properties in comparison to those of untreated fiber composites. SEM investigation showed that the surface modification of fiber has better fiber-matrix interaction. Thus, chemical treatments on the fiber improve fiber/matrix adhesion especially for silane on alkalized fiber treatment.

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Phenolic Resins and Composites

Frollini

Castellan

2012

Wiley Encyclopedia of Composites

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One of the major contributions of phenolic resins is their use as a matrix in fiber‐reinforced composites to prepare materials with low fire‐smoke toxicity coupled with favorable economics and excellent properties. New formulations became available in the 1980s and were developed mainly to meet requirements of the mass‐transit fire code, which allowed the application of phenolic composites in new areas, such as in mass‐transit car interiors and architectural and marine components. These facts, along with their properties, led to a favorable conjunction for phenolic composites, making them widely used when the requirements of both public and worker safety are of primary importance. Currently, there are basically three types of phenolic resins: the traditional resoles and novolacs and the more recent polybenzoxazines. Lignin, a phenolic biopolymer present in wood and non‐wood plants, is a by‐product of the pulp and paper industry. The growing number of biorefineries in many countries, aiming to convert lignocellulosic wastes into fuels and chemical raw materials, will lead to the availability of large quatities of lignin, which gives it strategic importance as a substitute of phenol in phenolic resins. Aside from lignins, the condensed tannins, also obtained from renewable sources, are suitable to prepare a phenolic‐type polymeric matrix because of the presence of phenolic rings with a larger number of free positions where the electrophilic attack can occur. To decrease the dependence of phenol–formaldehyde (PF) resins on formaldehyde, and hence their formaldehyde emissions, phenolic–furfural (PFu) resins have been developed. In addition, the low vapor tension and low toxicity of glyoxal (OHC–CHO) solutions represent some of the advantages of using glyoxal instead of formaldehyde for many applications. Concerning the reinforcement of phenolic‐type composites, the properties required for a particular application, along with other questions such as cost, define the fiber to be used as reinforcement. The prerequisites for a given application define the fiber length, the diameter, and the need for surface modifications of the fiber, among other characteristics. In addition to the traditional fibers used (as glass, carbon, aramids), agro‐fibers can be mentioned, going by the growing interest this material has aroused. Lignocellulosic fibers are particularly interesting as plastic reinforcements because of their low cost, low density, process flexibility, and modest equipment requirement. These fibers are renewable, widely grown, moldable, anisotropic, nonabrasive, porous, viscoelastic, biodegradable, compostable, and reactive. Lignocellulosic fibers have many hydroxyl groups on the surface, mainly from cellulose and lignin, which may interact easily with the phenolic or lignophenolic polar matrices. The use of nanofibers or nanoparticles as reinforcement can be highlighted, as they can improve several properties of the related composite, such as thermal, flame, chemical, and moisture resistance, and decreased permeability. The set of properties of phenolic‐type matrices, as well as both the flexibility to make changes in their formulations and possible use of different reinforcements, in addition to their favorable cost/performance characteristics, place these materials in a prominent position in relation to other thermoset matrix composites.

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Thermoset matrix reinforced with sisal fibers: Effect of the cure cycle on the properties of the biobased composite

Cited by 61 publications

References 28 publications

Resíduos de sisal como reforço em compósitos de polipropileno virgem e reciclado

Resíduos de sisal como reforço em compósitos de polipropileno virgem e reciclado

Effect of Chemical Treatment on Mechanical and Water-Sorption Properties Coconut Fiber-Unsaturated Polyester from Recycled PET

Phenolic Resins and Composites

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