Coir Fibres II: Evaluation as a Reinforcement in Unsaturated Polyester Resin Composites

Hybrid laminates consisting of glass fiber mat, chopped bristle coir fibers and un saturated polyester resin matrix were fabricated. Effect of treatment of coir fibers with alkali and dichloro methyl vinyl silane on the mechanical properties of the laminates was investigated. The hybrid composites having 66% resin (w/w) and 19.7% chopped coir fiber (1cm long) showed 35% improvement in flexural strength and 70% in flexural modulus over the neat polyester resin sheets. Mechanical properties of laminates increased on increasing the coir fiber length up to 1 cm beyond which a decrease in strength was observed. Hybrid laminates fabricated from NaOH treated coir fibers had better mechanical properties than those fabricated from untreated coir fibers. A decrease in thermal conductivity was observed with increasing weight fraction of coir fibers.