Study On Preparation And Properties Of EPDM/PP Thermoplastic Elastomer

The preparation of EPDM/PP thermoplastic elastomer by Dynamic vulcanization method, it has became a very useful polymer materials in recent years. Because of its simple processing, low cost, short molding cycle, can manufacture in a continuous manner and recycle utilization. It has gradually replaced rubber to use in automotive, electronic, building and so on many kinds of fields. So base on the above, the dynamic vulcanization for preparation of EPDM/PP thermoplastic elastomer was researched in this article. The EPDM/PP thermoplastic elastomer mechanical properties, microstructure, dynamic rheological behavior, heat resistant and the degradation properties of products were studied respectively.1. The priority crosslinking agent phenolic resin (1045), stannous chloride (Sncl2 · H2O) and zinc oxide (ZnO) as the auxiliary crosslinking agent were determined. The double screw extrusion machine was applied to prepare EPDM/PP thermoplastic elastomer (TPV) successfully. TPV Gel content could approach 96%, It has been shown by SEM that, cross-linked EPDM particles adequate distributed in PP, it was knew as the typical two phase structure and rubber particle was micron-sized. TG analysis showed that, compared with EPDM, TPV heat resistant performance improved greatly, Initial decomposition temperature increased 71℃.2.The influence of curing system constituent content, EPDM and PP properties, the blending ratio of EPDM/PP were investigated, The results showed that PP melt index has greatly influenced to TPV mechanical properties. Along with the PP melt index reduced, TPV tensile strength and tear strength increased, but the elongation at break reduced. TPV that has used PP copolymer, the tensile strength and tear strength were less than the samples that used PP homopolymer. But it could hold an advantage in elongation at break. When EPDM ethylene segment content and mooney viscosity increased, TPV tensile strength, tear strength and elongation at break also increased. TPV strength mainly depended on the content of PP plastic phase. rubber and plastic ratio decreased, TPV material’s tensile strength, tear strength strength and hardness increased.3.The plasticizer types and content impact on TPV’s performance were researched. When plasticizer was joined, TPV tensile strength, tear strength and hardness has decreased obviously. SEM showed that the phase interface became more uniform. TG thermal analysis showed that TPV thermal weight loss has two stages. And plasticizer could improve TPV processing performance.4.The influence of different molecular weight’s compatibilizer (SEEPS) to TPV was studied. The results showed that, when SEEPS was accessed, TPV tensile strength, elongation at break and tearing strength were enhanced. SEM pictures showed that phase interface was improved, rubber phase distribution became more uniform. TG thermal analysis confirmed that TPV could keep good heat resistant properties. At the same time, the different processing methods about how to join SEEPS was studied. The result showed two foot method could make TPV mechanical properties better, especially the permanent compression performance has improved remarkably.5.The Kssinger, Flynn-Wan-Ozawa and Friedman methods were used to research TPV’s non-isothermal thermal degradation kinetics. Separately calculated activation energy of degradation were 296.2 KJ/mol,323.1 KJ/mol and 303.9 KJ/mol. Compared with the EPDM was not crosslinked, activation energy of degradation was increased. At the same time, the isothermal thermal degradation kinetics was used to calculate TPV’s isothermal degradation activation energy, It was 262.2 KJ/mol. And through it, TPV heat aging life was estimated.6.The influence to dynamic rheological behavior of EPDM/PP was researched by different molecular weight of SEEPS. The results showed that the addition of SEEPS increased the complex viscosity, storage modulus and loss modulus. And along with the increase of the molecular weight, the dynamic parameters has became more higher and the elastic effect of melt was growth dramatically. The two step got the TPV’s dynamic rheological parameters more lower than one step.