Effect of concentration of coupling agent on mechanical properties of coir–polypropylene composite

Abstract

Coir fiber and polypropylene (PP) composites were prepared using m-isopropenyl-α-α-dimethylbenzyl isocyanate grafted polypropylene as a coupling agent. The effect of concentration of coupling agent on mechanical properties (tensile, flexural and impact) was investigated and discussed. The mechanical tests indicate that tensile and flexural strength increases with increase in concentration of coupling agent. The optimum loading capacity of coupling agent was 5 %. Increase in tensile and flexural strength may be attributed to improved wetting and interaction between PP and coir fiber. However, their was no effect of coupling agent concentration on tensile or flexural modulus. The impact strength of composite was also investigated which showed that notched impact strength reduces with increase in coupling agent concentration, while un-notched impact strength increases with increase in coupling agent concentration.