New polymeric-coupling agent for polypropylene/wood-flour composites

The suitability of using polypropylene modified with an organosilane as a coupling agent for polypropylene/wood-flour composites was investigated. The tensile properties, the water-absorption behavior, the thermal degradation properties and the morphology of the composites were analyzed and compared with those of non-coupled composites and of composites coupled with polypropylene modified with maleic anhydride. The coupling agents were prepared in the laboratory and it was verified that the silane showed higher reactivity towards PP chains. The results indicated that the silane-modified polymer increased the interfacial adhesion between the fibers and the polymer matrix and this effect was better than that obtained for the maleated-polypropylene-coupled composites.