Thermal decomposition behavior of foaming agent and its influence of gas yield on properties of microporous PP⁃based wood⁃plastic composites

doi:10.19491/j.issn.1001-9278.2025.11.005

Abstract

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

CLC Number:

TQ325.1⁺4

WANG Suwei, HU Ping, ZONG Huzeng, XUE Ping. Thermal decomposition behavior of foaming agent and its influence of gas yield on properties of microporous PP⁃based wood⁃plastic composites[J]. China Plastics, 2025, 39(11): 27-31.

Figures/Tables 8

原料组分	PP	POE	木粉	PP⁃g⁃MAH	滑石粉	发泡剂
质量比/份	42	28	30	10	10	1

Tab.1. Composition formula of wood plastic composite materials

Fig.1. Thermal stability of different foaming agents

Fig.2. Microscopic morphology and bubble size distribution of samples

Fig.3. Pore structure parameters of wood plastic specimens

Fig.4. Mechanical properties of wood plastic specimens

Fig.5. Microscopic morphology and bubble size distribution of samples

Fig.6. Pore structure parameters of wood plastic specimens

Fig.7. Mechanical properties of wood plastic specimens

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