Studies on natural fiber reinforced isotactic polypropylene-ethylene-octene copolymer blend composites

Blends of isotactic polypropylene (iPP) and ethylene-octene-copolymer (EOC), having different proportions, were prepared in a co-rotating twin screw extruder. The tensile and flexural properties of iPP-EOC blends containing up to 20% EOC content were determined. Impact strength of blend containing 5% EOC increased drastically to the tune of > 200% whereas the modulus and strength decreased marginally. The effect of EOC content on the mechanical properties was found to be linear suggesting uniform dispersion of EOC domains in polymer matrix. Various proportions of treated sisal and banana fibers were blended with iPP-EOC blend containing 5% EOC polymer matrix by melt blending technique. Both tensile and flexural properties increased whereas impact strength decreased with increase in fiber content. The extent of reinforcing effect of both sisal and banana fiber on iPP-EOC matrix is at comparable level. The melting point of composites was lower than virgin iPP, and the degree of crystallinity of composites was found to be lower than virgin iPP but higher than iPP-EOC blend. The extent of decrease in melting point and degree of crystallization remained same in both banana and sisal fiber composites. Thermal stability of composites was found to be lower than virgin iPP and iPP-EOC blend. Poor adhesion between polymer matrix and fiber was observed.