Composite Materials Based on Natural Rubber Modified Epoxy Resin and Sisal Fiber

In the present work, bisphenol-A based epoxy resin was blended with methyl methacrylate (MMA)/glycidyl methacrylate (GMA) grafted depolymerized natural rubber (GDNR). GDNR/epoxy resin blend was composite with woven sisal fiber. GDNR was prepared by solution grafting MMA/GMA (90/10 w/w%) onto depolymerized natural rubber (DNR). The occurrence of GDNR was confirmed by proton nuclear magnetic resonance spectroscopy (1H-NMR). Amount of GDNR in the blend was 1 part per hundred resins. Impact strength of epoxy resin was increased by 62% when GDNR was added. Composites of GDNR/epoxy resin and woven sisal fiber were prepared by hand-lay up process. Amounts of woven sisal fiber in the composite were 3, 5 and 7% by weight (wt%). The flexural modulus of the composites was higher than that of neat epoxy resin and increased with increasing amount of woven sisal fiber. Nevertheless, flexural strength of all composites was lower than those of neat epoxy resin and the blend. Compared to neat epoxy resin, the impact strength of the composite containing 7 wt% woven sisal fiber was further increased to 114%.