Avaliação da potencialidade do uso de fibras de Eucalyptus como reforço alternativo em compositos de silicona

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

In this study, silicone composites reinforced with short Eucalyptus pulp fibers were obtained. Composites were prepared with untreated fibers and also with fibers modified with three different silane coupling agents, as vinyltriethoxysilane, methyltriethoxysilane, and g-glicidoxypropyltrimethoxysilane, using THF or ethanol as a solvent. The fibers were characterized prior to and after chemical modification and the presence of silane coating on the fiber surface was observed by infrared, energy dispersive and X-ray photoelectron spectroscopies. The morphology of the fibers was investigated by field emission scanning electron, optical and atomic force microscopies. The surface treatment improved the adhesion at fiber-matrix interface, trough the formation of covalente bonds at modified fiber surface and silicone matrix. In composites obtained with silane/ethanol modified fibers, a better dispersion of fibers into the matrix was achieved, with a significam improvement in the tensile strength compared with that of the pure silicone matrix. However, the composites obtained with untreated and silane/THF modified fibers showed similar properties, what is explained by irregular distribution of fibers into the matrix. Consequently, the tensile properties of the composites were found to depend more on the fiber dispersion in the matrix than on the interface nature. The thermal stability of the composites was lower than that of the silicone matrix, with a distinct mechanism of degradation, due to the presence of the cellulosic fibers in these composites. In conclusion, the Eucalyptus fibers can be used as an alternative reinforcement in silicone composites for applications that do not require high load bearings.

ASSUNTO(S)

celulose siliconas compositos polimericos

ACESSO AO ARTIGO

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