Temperature scanning stress relaxation (TSSR) measurement of peroxide vulcanized polymer blends of polypropylene (PP) and ultrahigh molecular-EPDM (UHM-EPDM) rubber has been performed to study the thermomechanical behavior of thermoplastic vulcanizates (TPVs). Co-agents play crucial roles in the enhancement of properties of TPVs. Different types of co-agents (Triallyl cyanurate-TAC; N, N-m-phenylene-dimaleimide-HVA2; zinc dimethacrylate-ZDMA; and in-situ formed zinc dimethacrylate-ZMA) have been explored in this work. TSSR study shows that higher T₅₀ and T₉₀ values have been achieved in ZMA co-agent assisted-TPV. Higher TSSR-index (RI) value was also found for the same co-agent ZMA, indicating higher elastic behavior. TSSR result supports the mechanical and rheological properties, and it is found that the ZMA and ZDMA show higher mechanical strength. Cross-linked-density calculated by modified Flory–Rehner equation and the cross-link-density as obtained from TSSR method have been compared and the trend was found to be the same. Stress relaxation study shows the slow relaxation-phenomena of the ZMA-TPV with slowest relaxation-time (θ_r) than the other TPVs, which correlates with superior material strength. Thermogravimetric analysis proves that there is a difference in degradation temperature of the blends at approximately 5–10°C. Ultrahigh molecular weight-EPDM/PP based TPVs reveal superior thermomechanical and physico-mechanical properties with ZMA and ZDMA co-agent over TAC and HVA2. These ultrahigh molecular weight-EPDM based TPVs can be used in automotive seals/strips, hoses, bellows, and 2 K-molds for automotive applications.

中文翻译：

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通过温度扫描应力松弛测量探索过氧化物/助剂辅助热塑性硫化橡胶的热机械性能

已对聚丙烯 (PP) 和超高分子量三元乙丙橡胶 (UHM-EPDM) 橡胶的过氧化物硫化聚合物共混物进行温度扫描应力松弛 (TSSR) 测量，以研究热塑性硫化橡胶 (TPV) 的热机械行为。协同代理在增强 TPV 的性能方面起着至关重要的作用。不同类型的活性助剂的（三烯丙基cyanurate- TAC ; N，NM -亚苯基- dimaleimide- HVA2 ;锌dimethacrylate- ZDMA ;和原位形成的锌dimethacrylate- ZMA）在这个工作被探索。TSSR 研究表明，在 ZMA 助剂辅助 TPV 中已经实现了更高的T ₅₀和T ₉₀值。较高的 TSSR 指数 ( RI) 值也被发现用于相同的助剂 ZMA，表明更高的弹性行为。TSSR 结果支持机械和流变性能，发现 ZMA 和 ZDMA 显示出更高的机械强度。比较了由修正的 Flory-Rehner 方程计算的交联密度和由 TSSR 方法获得的交联密度，发现趋势相同。应力松弛研究表明，ZMA-TPV 的缓慢松弛现象具有最慢的松弛时间 ( θ _r) 与其他 TPV 相比，这与卓越的材料强度相关。热重分析证明共混物的降解温度在大约 5-10°C 之间存在差异。基于超高分子量 EPDM/PP 的 TPV 与 ZMA 和 ZDMA 助剂相比，显示出优于 TAC 和 HVA2 的热机械和物理机械性能。这些基于超高分子量 EPDM 的 TPV 可用于汽车密封件/条带、软管、波纹管和汽车应用的 2 K 模具。