The interface designing and reinforced features of wood fiber/polypropylene composites: Wood fiber adopting nano-zinc-oxide-coating via ion assembly

Wood-plastic composites (WPCs) with excellent water resistance, light absorption, mechanical properties, and thermal stability features were fabricated on an assembled nano-interface using cationic polyethyleneimine-nano-ZnO (PEI-ZnO) and anionic sodium polyacrylate-wood (PAAS-wood). The charge grafting, assembly, and dispersive morphology on the wood surface were analyzed by ZETA potentials, SEM images, crystal features, XPS and FTIR spectra. With a three dimensional shielding-assembling nano-network, water absorption of wood-polypropylene composite decreased from 5.20 wt.% to 1.83 wt.%, and the decomposition temperature (Td) of wood and polypropylene were enhanced by 114 °C and 63 °C depending on passing and hindering. The tensile strength and the glass transition temperature (Tg) were enhanced from 20.42 MPa, 11.7 °C to 38.73 MPa, 33.21 °C, respectively, likely due to firmed nano-dispersion, strong interfacial adhesion, and sufficient load transfer. In addition, ultraviolet and near-infrared resistance of the composite were found to be promoted by adopting the assembled nano-interface.