Flammability, thermal stability, and mechanical properties of wood flour/ polycarbonate/polyethylene bio-based composites

Fire risk limits further commercial utilization of bio-based composites. In this study, polycarbonate (PC) hybridization improved the fire retardancy and the mechanical properties of wood flour/high-density polyethylene (HDPE) bio-based composites. A boric acid treatment improved the thermal stability of wood flour; the latter was then combined with the PC and the HDPE to produce hybrid-polymer-based composites. This study characterized the chemical structure, microstructure, and properties of the resulting bio-based composites. Results showed that the PC dispersed in the polyethylene matrix as micro or nanoparticles. The addition of PC increased the thermal stability of the resulting composites, and the char residue rate increased by 6.7 % at a PC content of 28 %. PC particles acted as a nucleating agent for the crystallization behavior of the bio-based composites. Adding PC reduced the heat release rate of the composites upon combustion. The tensile strength and modulus of elasticity of the resulting composites increased by 27.7 % and 91.1 %, respectively. Meanwhile, flexural strength and elasticity increased by 22.7 % and 53.8 %, respectively. The creep strain of the composites gradually decreased with increasing PC content, indicating that the addition of PC increased the anti-creep properties of the composites. Thus, the plastic hybridization and the wood flour fire retardant treatment led to bio-based composites with improved strength, thermal stability, and inflammability by wood flour modification.