偶氮复合发泡剂对交联聚氯乙烯泡沫结构和性能的影响

采用异氰酸酯和环氧树脂作为交联剂，偶氮二异丁腈（AIBN）和偶氮二甲酰胺（AC）作为发泡剂制备了交联聚氯乙烯泡沫材料。 通过扫描电子显微镜分析了两种发泡剂的粒径、比例以及用量对泡孔结构的影响。 结果表明，AIBN的粒径对泡沫的泡孔结构影响不大，但其用量增加导致泡沫密度减小；AC的粒径对泡孔结构产生一定的影响，最优的粒径范围为8～20 μm，并且随着用量增加，泡孔尺寸变小，但对密度影响不大。 采用DSC研究了AIBN和AC在预混料中的分解情况，提出了两种发泡剂影响泡沫的泡孔结构的机理。 对泡沫材料力学性能的分析表明，泡沫的强度随密度的增加而增加，剪切变形则在60～80 kg/m3密度范围内出现最大值。

Effect of Foaming Agents on Structure and Properties of Crosslinked Polyvinyl Chloride Foam

Polyvinyl chloride(PVC) foam cross-linked by isocyanate and epoxy resin was prepared. Both azobisisobutyronitrile(AIBN) and azodicarbonamide(AC) were used as foaming agents in the prefoam process. Morphologies of foams were characterized by SEM. The effects of particle size, proportion, loading of foaming agents were investigated. The particle size of AIBN has no effect on the cell structure, but the increase of AIBN loading leads to a lower density. The effect of AC particle size on the cell structure is obvious, and the optimal size is 8~20 μm. The cell size mainly depends on the loading of AC. Decomposition of foaming agent was studied by DSC. Both the decomposition behavior of mixed foaming agents and the nucleating effect of AC for the prefoam determine the cell morphology of the resultant foams. The strength increases with the increase of density, but the maximum shear strain appears in the foams with the density of 60~80 kg/m3.