Construction and functional effects of a compatible nano-TiO2 interface between wood fiber and polypropylene via adopting chemical polyethyleneimine–(3-aminopropyl) triethoxysilane assembly on the fiber surface

A simple chemical assembly to construct a compatible nano-TiO2-coating on a wood surface has been reported using polyethyleneimine and (3-aminopropyl) triethoxysilane for recycled wood–polypropylene composites (WPCs). Crystal features, ZETA potential, and FTIR analysis indicated that the assembly was stable and sufficient, which could be verified further using SEM imaging. Via a three-dimensional hydrophobic network in the composite, water absorbance decreased from 2.89 wt% to 0.72 wt%. Ultraviolet and near-infrared resistance were found to be increased for the dispersive nano-network in the composite matrix. In particular, when the assembling nano-interface was 2.0 wt% for the composite, as well as the tensile strength, the elongation at break was enhanced by about 85%. Tg was also enhanced for strong interfacial adhesion and sufficient load transfer. Also, due to the shielding of the nano-network and the coupling aspect of the assembly, the decomposition temperature (Td) of wood and polypropylene were enhanced by 79 °C and 27 °C, respectively.