The Effects of Alkalized and Silanized Woven Sisal Fibers on Mechanical Properties of Natural Rubber Modified Epoxy Resin

Bisphenol-A based epoxy resin was modified by blending with 1% by weight (wt%) of methyl methacrylate (MMA)/glycidyl methacrylate (GMA) grafted depolymerized natural rubber (GDNR). The blend showed the impact strength of 163% higher than that of neat epoxy resin. In order to study the effect of alkalized and silanized woven sisal fiber on the properties of 1 wt% GDNR/epoxy resin blend, alkalized woven sisal fiber was prepared using 2 wt% NaOH solution and silanized fiber was prepared by treated alkalized fiber with γ-glycidoxypropyltrimethoxysilane (A-187). Composites of the blend with alkalized and silanized woven sisal fiber were manufactured by hand-lay up process. Amounts of woven sisal fiber in the composite were 3, 5 and 7 wt%. The flexural modulus of all composites was higher than that of the blend and increased with increasing the amount of fiber. In addition, when silanized sisal fiber was used, the composites showed further improvement in flexural modulus. Flexural strength of all composites was lower than that of the blend but it was improved after silanized sisal fiber was employed. Compared to GDNR/epoxy resin blend, the impact strength of the composite containing 7 wt% silanized sisal fiber was significantly enhanced to 230%.