Improvement of Rice Husk/HDPE Bio-Composites Interfacial Properties by Silane Coupling Agent and Compatibilizer Complementary Modification

Composites using agricultural and forestry residues as raw materials with potentially high-performance, multifunctional and biodegradable ecological advantages, are viewed as very promising for new-generation lightweight and low-cost bio-based sustainable building materials. At present, the research on wood-plastic composite materials is relatively mature. However, it is still a challenge to effectively use other biomass and improve the interface of the high-polymer compound system. Herein, we proposed a simple and effective method to enhance the interfacial adhesion properties of rice husk fibre and High Density Polyethylene (HDPE) composites by the silane coupling agent KH-550 and compatibilizer Maleic anhydride grafted polyethylene (MAPE) with complementary modification. It was found that the coupling agent KH-550 cross-linked with the hydroxyl group on the husk fibre surface and solidified with the high polymer by –NH–, –C=O– functional group generation. Compatibilizer MAPE strengthened the two phases by covalently bonding with an ester linkage and lowered the roughness of the cross-section of the composites. Meanwhile the modification enhanced the dispersibility, and mechanical properties of the husk-high polymer compound system, the bending and flexural strength were improved by 11.5% and 28.9% with KH-550, and MAPE added, respectively. The flexural strength of the composites increased by 40.7% after complementary modification. Furthermore, the complementary modification treatment reduced the hydrophilic hydroxyl groups and increased the molecular chain to improve the water-resistance, elastic modulus and toughness of the composite. This study prepared a bio-composite, which is expected to expand the use of agricultural and forestry residues as an extension of wood-plastic composites.