Mullins effect under tearing mode and its reversibility of ethylene-vinyl acetate copolymer/chloroprene rubber thermoplastic vulcanizates

Abstract

Thermoplastic vulcanizate (TPV) based on ethylene-vinyl acetate copolymer (EVA)/chloroprene rubber (CR) blends were prepared by dynamic vulcanization. Its micromorphology, tearing strength, Mullins effect and reversible behavior and its mechanism under tearing mode at different heat treatment temperatures were investigated. The results showed that the strain and tear strength of EVA/CR TPVunder tearing mode were higher when the rubber-plastic mass ratio was 30/70, and the rubber phase and resin phase presented a “sea-island” structure. A significant Mullins effect was displayed during the uniaxial cycle loading-unloa-ding under tearing mode of EVA/CR TPV. The ma-ximum tear strength, residual deformation, internal friction and damping factor were increased with increasing of strain under tearing mode in the cycle uniaxial test, while the degree of stress softening effect tended to decrease. With increase of heat treatment temperature, the recovery ability of EVA/CR TPV was significantly improved, and the best reco-very temperature was 70 ℃.

Keywords

• ethylene-vinyl acetate copolymer
• chloroprene rubber
• tearing mode
• mullins effect
• reversibility behavior