关键词: 木塑复合材料, 聚丙烯, 发泡剂, 挤出成型, 微孔塑料

Abstract:

To address the high density and low toughness of conventional wood⁃plastic composites （WPCs）， this study employed chemical foaming technology to introduce a microcellular structure into the material. Subsequent crack passivation and other methods were applied to achieve simultaneous enhancement and toughening， thereby facilitating high⁃performance applications of WPCs. Using azodicarbonamide （ADC） and sodium bicarbonate （SBC） as foaming agents， the influence of their pyrolysis behavior on cellular morphology was investigated through thermal stability analysis. Formula optimization was further conducted to examine the effect of gas production rate on the mechanical properties of the composites. The results indicated that， compared to SBC⁃based foam masterbatch， ADC foaming agent compounded with zinc oxide was easier to yield a “fine and dense” microcellular structure. At an optimal dosage of 1 phr， a microporous structure with an average cell size of 71 μm and a cell density of 2.7×10⁴ cells/cm³ was achieved. The corresponding impact strength， tensile strength， and flexural strength of the composite reached 6 kJ/m²， 9.7 MPa， and 22.1 MPa， respectively.

Key words: wood plastic composite material, polypropylene, foaming agent, extrusion molding, microporous plastic