聚丙烯共混体系制备及其发泡性能研究

Preparation and Foaming Properties of Polypropylene Blending System

以低熔点聚丙烯(LPP)与高熔点聚丙烯(HPP)的共混物为原料,CO2作为发泡剂,使用自制高压反应釜进行发泡。采用差示扫描量热仪和旋转流变仪剖析共混物的热行为与流变行为,通过扫描电子显微镜分析发泡后的泡孔形态。结果表明:HPP的加入使共混物的熔融温度与结晶温度向高温方向移动,HPP作为物理交联点,可显著提高共混物的熔体强度,减少泡孔合并与坍塌,提高泡孔密度,泡孔直径明显减小。

Using low melting point polypropylene(LPP)and high melting point polypropylene(HPP)blends as raw materials,CO2 as foaming agent,self-made autoclave was used for foaming.The thermal and rheological behavior of the blends were analyzed by DSC and rheometer,and the foam morphology was analyzed by scanning electron microscopy.The results show that the melting temperature and crystallization temperature of the blends move towards high temperature with the addition of HPP.As a physical crosslinking point,HPP can significantly improve the melt strength of the blends,reduce the coalescence and collapse of bubbles,increase the density of bubbles and decrease the diameter of bubbles.