Nano silicon carbide-treated wheat straw fiber reinforced high-density polyethylene composites

In the present work, we innovatively used nano-silicon carbide (nano-SiC) with high specific surface area and high rigidity to modify wood-plastic composites, and investigated the effect of nano-silicon carbide content on wheat straw fiber (WSF) and on WSF-reinforced high-density polyethylene (HDPE) composites was investigated. Vinyltrimethoxysilane (A171) was employed as a coupling agent to improve the compatibility between WSF, nano-SiC and HDPE matrix. The results showed that the crystallinity of the treated WSFs were improved. Compared with the untreated fiber-reinforced composites, nano-SiC improved the mechanical properties of the composites, especially with nano-SiC content of 0.4 wt%, the tensile strength, flexural strength, and flexural modulus increased by 15.5%, 11.5%, and 12.4%, respectively. And the water absorption properties were also significantly improved, but the thermal stability decreased slightly. Scanning electron microscopy (SEM) showed that the addition of nano-SiC reduced the cracks and pores on the surface of the composites as well as the tensile fracture cross section, which indicated that the dimensional stability and interfacial properties of the composites were improved. • WSF/HDPE modified composites were prepared by melt–blending and injection molding. • The silane coupling agent acted as a bridge to form a structural network. • When nano-SiC was added at 0.4 wt%, the enhancement of mechanical properties of the WSF/HDPE was relatively significant. • The water absorption and thermal behavior were also investigated.