动态硫化过程中EPDM/PP热塑性弹性体的相态演变及流变行为

Morphology Structure in the Process of Dynamic Vulcanization and Rheological Property of EPDM / PP-TPV

采用转矩流变仪制备三元乙丙橡胶/聚丙烯热塑性弹性体(EPDM/PP-TPV)。通过扫描电子显微镜观察二甲苯蚀刻后样品低温脆断面,并用旋转流变仪测试EPDM/PP-TPV的流变性能。扫描电镜分析结果表明,EPDM的充油量对EPDM/PP-TPV的相态结构有明显的调控作用,充油量达到30%时,体系分散程度最佳,硫化过程可实现相逆转;橡塑比对简单共混体系相态分布有明显调控作用,对动态硫化体系相态分布影响不大;适当提高转速会改善体系分散程度,转速为50 r/min时,交联EPDM颗粒粒径最小。流变性能测试结果表明,EPDM/PP-TPV试样在低频末端区会出现"第二平台",充油量为30%时,复数黏度最低,分散程度达到最佳,与扫描电镜分析结果一致;储能模量和损耗模量随着橡塑比的增大而增大,当橡塑比达到50/50时,整个频率范围内储能模量大于损耗模量;转速对EPDM/PP-TPV的复数黏度影响不大,转速为50 r/min时,储能模量达到最大值。

Ethylene-propylene-diene terpolymer / polypropylene thermoplastic vulcanizate( EPDM / PP-TPV) was prepared by a Haake batch mixer. Morphology structure and rheological property of EPDM / PP-TPV were investigated through scanning electron microscope and rotational rheometer. The results show that morphology structure of EPDM / PPTPV was strongly influenced by the content of naphthenic oil. The 'second plateau'is observed at low frequency,complex viscosity and degree of the dispersion is the best when the content of naphthenic oil is 30%. The mass ratio of rubber to plastic has obvious regulating effect on the morphology structure of EPDM / PP blends,however,no severe regulating effect is observed in dynamic vulcanization system. Storage modulus and loss modulus increase with increasing the mass ratio of rubber to plastic. The rotational speed has no significant effect on the complex viscosity,the storage modulus of crosslinked EPDM particles reaches the minimum when the rotational speed is 50 r / min.