Optimization of Rubber Domain Morphology in Thermoplastic Elastomer Blends for Improved Resilience

Thermoplastic vulcanizates (TPVs), a class of thermoplastic elastomer blends, have recently gained significant attention as eco-friendly options for various industries owing to their combined advantages of recyclability and weight reduction. However, their low resilience compared to that of conventional rubber hampers their practical application. In this study, we enhance the elastic properties of typical polypropylene/ethylene propylene diene monomer (PP/EPDM) TPVs by introducing montmorillonites (MMTs) into the EPDM rubber domains using a compatibilizer. Nanocomposite TPVs are fabricated by using a three-step dynamic vulcanization process that is closely monitored for torque changes. The nanocomposite exhibits a higher degree of cure and improved elastic recovery (compression set = 42.0%) compared to TPVs without MMTs (compression set = 47.9%), which we attribute to the reduction in rubber domain size from 0.86 to 0.51 μm owing to the incorporation of MMTs. Combined with the tunable mechanical properties and well-balanced performance achieved through precise control of polymer phases, the developed nanocomposite TPVs and their fabrication methodology provide valuable insights into polymer blends, offering significant potential for expanding the TPV application fields.