高速铁路垫片TPEE的注射微发泡性能研究

Research on Porperties of Injection Foamed TPEE Used for High Speed Railway Gasket

应用可发泡的特种模具注射成型了热塑性聚酯弹性体(TPEE),探讨了在注射成型中TPEE发泡的结构形态与性能。通过改变物料配比,得到TPEE在不同工艺条件下的形态和性能。通过对制品的性能测试,得出TPEE注射成型的最佳配比和工艺条件,复合发泡母粒由吸热性发泡剂和放热型发泡剂以AC/NaHCO3/柠檬酸=2/1/1配比制成。测试结果表明,发泡助剂ZnO的加入不仅促进了气泡核的形成还可以促进AC的活化分解,使发泡体系的发泡温度下降,当ZnO含量为1份时,泡孔大小均一,分布均匀;加入挤出成型方法制备的聚苯乙烯—聚乙烯—聚丁烯—聚苯乙烯嵌段共聚物接枝甲基丙烯酸缩水甘油酯(SEBS-g-GMA),可以提高发泡体系的相容性,当SEBS-gGMA含量为6份时,TPEE制品力学性能最好;注射压力的大小对发泡TPEE制品的微观结构影响很大。

Thermoplastic polyester elastomer （TPEE） was injected through expandable special mold, the structure and properties of foamed TPEE in injection molding were discussed. The morphology and properties of TPEE in different conditions were getted through change of material ratio. The best proportion and process conditions of TPEE in injection molding was getted by properties test, composite foaming masterbatch was made of endothermicblowing agent and exothermie foaming agent based on AC/NaHCO3 /citric acid =2 / 1 / 1. Test results show that the addition of foaming agent ZnO not only promote formation of cell nuclei but also activate dissociation of AC to decrease the foaming temperature. When the content of ZnO is 1 phr, the bubble size is distributed and uniform. Addition of polystyrene - polyethylene -polybutene - polystyrene block copolymer grafting of glycidyl methacrylatethe （SEBS-g-GMA） synthesized by extrusion molding process can improve compatibility of the foaming system. When SEBS-g-GMA is 6 phr, the mechanical properties of TPEE products is the best. Injection pressure has great impact on microstructure of TPEE foam products.