Improving dimensional stability and durability of wood polymer composites by grafting polystyrene onto wood cell walls

Abstract

Wood polymer composites (WPCs) were prepared in this study by grafting polystyrene onto poplar wood cell walls through free‐radical copolymerization methods. Methacryloyl chloride was first employed to cause swelling and react with the hydroxyl groups on the wood cell walls. Styrene monomers were then copolymerized with the methacryl groups in situ. The resultant WPCs were observed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The physical and mechanical properties of the composites, including dimensional stability, water uptake, dynamic hydrophilicity, surface hardness, and thermal stability, were also evaluated. Results suggest that methacryl groups and styrene were successfully copolymerized, and that the resultant copolymer was grafted onto the wood matrix through the reaction of methacryl groups and hydroxyl groups on wood components. Graft copolymerization not only significantly improved the interfacial compatibility between the polymer and wood substance, but also provided the wood with higher dimensional stability, better hydrophobic properties, and enhanced surface hardness. POLYM. COMPOS., 39:119–125, 2018. © 2016 Society of Plastics Engineers