Effect of phosphate treatment on interfacial properties of poplar fiber/high-density polyethylene composites

Poplar fiber was treated with phosphate solution as a modifier and then wood fiber/high-density polyethylene (HDPE) degradable composite was prepared by melt blending with HDPE. The effects of phosphate solution concentration on tensile strength and flexural strength of composites were investigated. The surface morphology of phosphate-treated poplar fibers was observed by scanning electron microscopy. The results show that the phosphate treatment increases the surface roughness of the poplar fiber, increases the strength of the single fiber, and effectively improves the mechanical adhesion to the HDPE matrix. However, when the phosphate concentration is too large, the density of the cellulose molecular chains is lowered, and the mechanical properties of the whole fiber are lowered. When the concentration of phosphate solution is 3%, the treatment time is 4 h, and the treatment temperature is 60°C, the tensile properties, bending properties, and water resistance of poplar fiber/HDPE composites are the best.