辐照改性聚丙烯拉伸流变行为及其挤出发泡的研究

通过在线形聚丙烯中加入双官能团丙烯酸酯类单体,经小剂量γ射线高能辐照,制备了高熔体强度聚丙烯,研究了其拉伸流变行为及其在挤出发泡方面的应用。Rheotens拉伸流变测试表明,辐照改性后由于形成了长支化分子结构,聚丙烯的熔体强度、拉伸黏度显著提高,具有明显的应变硬化特征。实验表明,ZnO可明显降低AC发泡剂分解温度,缓和分解放热;在辐照改性制备的高熔体强度聚丙烯中加入AC／ZnO复合发泡剂,可挤出发泡得到泡孔尺寸较为均一、分布均匀、具有闭孔结构的发泡材料。

Extensional Rheologicai Behavior of Irradiated Polypropylene and Its Application in Extrusion Foaming

Polypropylene was mixed with a small amount of bi-functional acrylate and was subjected to y-irradiation. Due to the generation of long-branching structure, the melt strength and extensional viscosity of polypropylene were greatly increased and exhibited a strain hardening behavior, thus was suitable for extrusion foaming. With high melt strength, polypropylene foam with uniform close-pores was successfully prepared with AC/ZnO as a composite foaming agent. It was demonstrated that zinc oxide could activate azodicarbonamide(ADC) leading to a lower decomposition temperature and a smaller heat release.