BIOFIBER-REINFORCED POLYPROPYLENE COMPOSITES

Biofibers, natural lignocellulosics, have an outstanding potential as a reinforcement in thermoplastics. This study deals with tile preparat ion of lignocellulosic composites by reactive extrusion processing in which good interfacial adhesion is generated by a combination of fiber modification and matrix modification methods. PP matrix was modified by reacting with maleic anhydride and subsequently bonded to the surfa ce of the modified lignocellulosic component, in-situ. The fiber surfa ce was modified by reacting it with a silane in a simple and quick aqu eous reaction system, similar to that employed for glass fibers. The m odified fibers are then extruded with the modified polymer matrix to f orm the compatibilized composite. The various reactions between the li gnocellulosic fiber/filler and modified polymer chains, is expected to improve the interfacial adhesion significantly as opposed to simple m ixing of tile two components, since new covalent bonds between the fib er surface and matrix are created in the former case. These composite blends were then injection molded for mechanical characterization. Typ ical mechanical tests on strength, toughness and Izod impact energy we re performed and the results are reported. These findings are discusse d in view of the improved adhesion resulting from reactions and enhanc ed polar interactions at phase boundaries.