超临界N_2及CO_2注塑发泡聚丙烯性能对比研究

Comparative Study on the Properties of Injection Foamed Polypropylene by Using Supercritical N_2 and CO_2

采用具有二次开模功能的注塑发泡机,对比研究了不同开模距离条件下超临界氮气(N_2)以及二氧化碳(CO_2)对改性聚丙烯(PP)的发泡性能。研究发现,相同的开模距离条件下,超临界N_2发泡PP相比超临界CO_2发泡PP具有更多更小的泡孔,具有更高的减重比例;减重比例大,力学性能保持率则较低。而开模距离越大,泡孔更容易发生合并的现象。

The comparison of foaming properties of polypropylene(PP) with supercritical nitrogen(N2) and carbon dioxide(CO2) as the foaming agents by injection foaming machine with core-back function was investigated. The results show that at the same core-back distance supercritical N2 foamed PP has smaller cell sizes than supercritical CO2 foamed PP,which means higher weight reduction. As the increase of the weight reduction,the retention of mechanical properties of PP is reducing. And as the increase of core-back distance,there would be more cell rupture and amalgamation.