化学发泡法制备发泡三元乙丙橡胶/聚丙烯热塑性硫化胶 Ⅰ.挤出工艺参数

Foamed ethylene-propylene-diene rubber/polypropylene thermoplastic vulcanizate prepared by chemical foaming Ⅰ. Extrusion processing parameters

以偶氮二甲酰胺(AC)为发泡剂,采用单螺杆挤出机制备了发泡三元乙丙橡胶(EPDM)/聚丙烯(PP)热塑性硫化胶(TPV),探讨了挤出温度、机头温度及螺杆转速对发泡TPV性能及形态结构的影响。结果表明,在保证EPDM/PPTPV充分塑化熔融及顺利挤出的前提下,较低的挤出温度和机头温度有利于制备密度低、泡孔尺寸小且分布均匀、表面光洁度高的发泡TPV,最佳的挤出温度和机头温度分别为185,170℃;随着螺杆转速的提高,发泡TPV的密度和拉伸性能均先降低后增高;泡孔平均直径基本不变,泡孔面密度先增大后减小,泡孔尺寸分布先变窄后变宽,最佳的螺杆转速为65r/min。

The foamed ethylene-propylene-diene rubber/polypropylene thermoplastic vulcanizate （EPDM/PP TPV） was prepared by single screw extruder using azodicarbonamide as chemical blowing agent. The effects of extrusion temperature, head temperature and screw rotation speed on properties and cell morphology of foamed TPV were explored. The results showed that under the premise of ensuring complete plasticization and melting of TPV as well as smooth extrusion, lower extrusion tempera- ture and extruder head temperature was of benefit to the preparation of foamed TPV with low density, fine and uniform cell or high surface quality. The optimal extrusion temperature and head temperature was 185 ℃ and 170℃ respectively. With the increase of screw rotation speeds, density and tensile properties of foamed TPV reduced first but then increased, average cell diameter kept constant, cell area density increased first but then decreased, and cell size distribution narrowed first but then broadened. The optimal screw rotation speed was 65 r/min.