Mullins Effect and Its Reversibility for Thermoplastic Vulcanizates Based on Ethylene–Acrylic Acid Copolymer/Nitrile–Butadiene Rubber Blends

Mullins effect during uniaxial cyclic compression tests, together with its reversibility, of ethylene–acrylic acid copolymer (EAA)/nitrile–butadiene rubber (NBR) thermoplastic vulcanizates (TPVs) were investigated systematically. The results showed that EAA/NBR TPVs had excellent mechanical properties when the weight ratio was 40/60. Morphology studies showed that sphere-like NBR particles were dispersed evenly in the etched TPVs surface with diameters of 5–8 μm. The experimental results of Mullins effect indicated that a stress softening phenomenon in the stress–strain curves of EAA/NBR TPVs during the uniaxial loading–unloading cycles could be observed obviously; moreover, the reversibility of Mullins effect could be significantly enhanced by increasing heat treatment temperature.