Mechanical, thermal, void fraction and water absorption of silane surface modified silk fiber reinforced epoxy composites

Abstract

In this research, the silk fibers that were successfully extracted from silk cocoons using Na2CO3 were treated with silane coupling agent (3-aminopropyl)trimethoxysilane. The silane treated and untreated silk fiber reinforced epoxy composites were fabricated using the hand lay-up technique. The effects of fiber loading and the presence of silane coupling agent on the mechanical, morphological, thermal, void fraction, and water absorption properties of the silk fiber reinforced epoxy composites were studied. Fourier transform infrared (FTIR) analysis confirmed presence of silane group on the surface of fiber. The void fraction and water absorption increased with increasing fiber loading for both untreated and silane-treated composites. However, the silane-treated composites displayed lower increment of both void fraction and water absorption in comparison to the untreated samples suggesting better properties. The impact, flexural and tensile properties of the treated composites exhibited better property enhancement compared to the untreated samples with optimum fiber loading was observed at 30 wt%. The presence of this coupling agent also increased the thermal properties of the composites in general. The morphological studies revealed good interfacial compatibility between fiber and matrix in the presence of silane coupling agent which consistent with the enhancement observed for impact properties.