高熔体强度聚丙烯注塑发泡能力评价

Evaluation on injection foamability of high melt strength polypropylene

采用凝胶渗透色谱仪和熔体强度仪研究了高熔体强度聚丙烯HMS20Z和通用聚丙烯PPH-T03的分子结构及熔体强度。结果表明:HMS20Z的相对分子质量分布较PPH-T03宽,宽相对分子质量分布有助于提高其熔体强度。在注塑发泡实验中,具有更高熔体强度的HMS20Z较PPH-T03可以承受更高的物理发泡剂N_(2)注气量,且在相同的工艺条件下,得到的制品具有更高的减重比和更均匀细腻的泡孔结构。随着N_(2)注气量的增加,注塑发泡制品的减重比提高,抗冲击性能下降。相同减重比时,HMS20Z制品的泡孔更细腻,因此抗冲击性能下降幅度更小。

The molecular structure and melt strength of high melt strength polypropylene,HMS20Z and general polypropylene,PPH-T03 were studied by gel permeation chromatography(GPC)and Rheotens melt strength tester.The results show that the molecular mass distribution of HMS20Z is wider than that of PPH-T03,which contributes to higher melt strength.HMS20Z is able to be injected more physical blowing agent nitrogen than PPH-T03 thanks to its higher melt strength in injection foam experiment,and whose product has higher weight loss ratio and more uniform cell structure.The weight loss ratio of the foamed products is increased and impact resistance is weakened when more nitrogen is injected.The injected foam products of HMS20Z declines more slightly in impact resistance than PPH-T03 with the same weight loss ratio due to its more delicate cell structure.