The effects of coupling/grafting modification of wood fiber on the dimensional stability, mechanical and thermal properties of high density polyethylene/wood fiber composites

In this study, unsaturated double bond was successfully introduced onto the surface of wood fiber (WF) by the coupling reaction with γ -(methacryloxypropyl) trimethoxy silane, and the grafting reaction between the coupled WF (c-WF) and high density polyethylene (HDPE) was initiated with the presence of an initiator in melt blending. The molecular bridge between WF and the HDPE matrix introduced by the coupling/grafting reaction could greatly improve the interfacial adhesion between them. The surface morphology and chemical composition of c-WF were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectroscopy, and the grafting of HDPE onto WF was confirmed by thermogravimetric analysis. The effects of coupling/grafting modification on the dimensional stability, mechanical and thermal performances of HDPE/WF composites were evaluated. The results clearly show that the composite with coupling/grafting modified WF (cg-WF) has better water resistance, mechanical and thermal properties than maleic anhydride grafted polyethylene compatibilized HDPE/WF composite. The performances of HDPE/WF composites can be further improved by combining coupling/grafting modification and compatibilizer.