Abstract: This paper reported an investigation on the effect of NaHCO3 and azodicarbonamide (AC) foaming agents on high-density polyethylene (PE-HD)/wheat straw wood-plastic composites. The PE-HD/wheat straw foaming wood-plastic composites were prepared by a hot-pressing method, and their various properties were investigated. The results indicated that the addition of foaming agents into the PE-HD/wheat straw wood-plastic composites could improve the mechanical and water-absorption performance significantly. AC foaming agent exhibited a better modification effect than NaHCO3, and the composites achieved the optimum performance with the Rockwell hardness of 82.9, tensile strength of 13.0 MPa, water absorption of 19.53 % and water contact angle of 83.2 ° at AC content of 1.5 wt %.

Key words: wood-plastic composite, foaming agent, mechanical property, water absorption, water contact angle