Nanostructured Thermoplastic Vulcanizates by Selectively Cross-Linking a Thermoplastic Blend with Similar Chemical Structures

Ethylene vinyl acetate rubber (vinyl acetate (VA) content = 50 wt %) (EVM) and ethylene vinyl acetate copolymer (VA content < 50 wt %) (EVA) are polymers with a very similar chemical structure. In this study, a novel thermoplastic vulcanizate (TPV) based on EVM/EVA28 (VA content = 28 wt %) blend has been successfully fabricated by dynamic vulcanization due to the selective cross-linking of EVM. The morphologies and properties of the TPVs have been investigated. It was found that the cross-linked EVM phase and the thermoplastic EVA28 phase form a perfect cocontinuous structure with the rubber phase size of about 100 nm. The fabricated TPV exhibits not only excellent stretchability (>900% elongation at break), nice elasticity (only about 19% remnant strain at 100% stretching), and good flexibility but also superior oil resistance.