Effect of poly(methylhydrogen)siloxane modification on adjusting mechanical properties of bamboo flour‐reinforced HDPE composites

Poly(methylhydrogen)siloxane (PMHS) was applied for hydrophobic modification of bamboo flour (BF) at room temperature based on the dehydrogenation between hydroxyl groups of BF and –Si–H of PMHS, and the effect of PMHS modification on mechanical properties of BF/HDPE (high-density polyethylene) (BF/HDPE) composites was investigated. It was found that the hydrophobicity of BF were significantly improved by PMHS modification, and the mechanical properties of BF/HDPE composites could be adjusted effectively. PMHS with reactive hydrogen content of 1.5 % was the best candidate modifier for improving the strength of BF/HDPE, while PMHS with reactive hydrogen content of 0.2 % is more suitable to improve the toughness of BF/HDPE. More importantly, with optimal weight ratio of PMHS to BF, the strength and toughness of BF/HDPE could be improved simultaneously. After a systematic discussion on the results of FTIR, XPS, SEM and the chemical structure of PMHS, the relationship between microstructure and properties of BF/HDPE composites was built and then the mechanism for PMHS modification on BF/HDPE composites was proposed.