Synergistic toughening effects of grafting modification and elastomer-olefin block copolymer addition on the fracture resistance of wood particle/polypropylene/elastomer composites

A novel wood particle/polypropylene/elastomer composites with good impact resistance and stiffness was prepared by adding elastomer-olefin block copolymer (OBC) and grafting maleic anhydride (MAH) on polypropylene/OBC blends. The grafted MAH greatly improved the interfacial interaction among polypropylene, OBC, and wood particle, resulting in an enhanced impact resistance, stiffness and dimensional stability of the resulting composites. The modified matrix and their composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, mechanical tests, and dynamic mechanical analysis. The results confirmed that with 60 wt% wood particles loading, the synergistic interactions between OBC blending and MAH grafting improved the impact strength of the MAH-grafted blends/wood particle composites by 49%, with stiffness comparable that of the MAH-grafted polypropylene/wood particle composites. The composites modified with MAH also revealed an enhanced interfacial adhesion among polypropylene, OBC, and wood particles, as evidenced by dimensional stability tests, dynamic mechanical analysis, and morphology observation.