Mechanical and Thermal Properties of Wood-Plastic Composites Reinforced With Hexagonal Boron Nitride

Mechanical and thermal properties of injection molded wood plastic composites (WPCs) were prepared from poplar wood flour (50 wt%), thermoplastics (HDPE or polypropylene) with coupling agent (3 wt%), and hegzagonal boron nitride (h-BN, 2, 4, or 6 wt%) nano powder were investigated. The flexural and tensile properties of WPCs significantly improved with increasing content of the h-BN. Unlike the tensile and flexural properties, the notched izod impact strength of WPCs decreased with increasing content of h-BN but it was higher than that of WPCs without the h-BN. The WPCs containing h-BN were stiffer than ones containing wood flour alone i.e., the partial replacement of h-BN with polymer had a synergistic reinforcing effect. The tensile elongation at break values of WPCs increased with the addition of h-BN. The differential scanning calorimetry (DSC) analysis showed that the crystallinity, melting and crystallization enthalpy of WPCs increased with increasing content of the h-BN. The increase in the crystallization peak temperature of WPCs indicated that hBN was the efficient nucleating agent for on thermoplastic composites to increase the crystallization rate. Based on the findings obtained from the present study, it could be said that the optimum content of h-BN in the WPC for structural applications was 4 wt%.