撕裂模式下乙烯-乙酸乙烯酯共聚物/氯丁橡胶热塑性硫化胶的Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-乙酸乙烯酯共聚物（EVA）/氯丁橡胶（CR）热塑性硫化胶（TPV），对其微观形貌、撕裂强度、撕裂模式下的Mullins效应、热处理后的可逆回复行为及其机制进行了研究。结果表明，EVA/CR TPV橡塑质量比为30/70时其撕裂模式下的应变和撕裂强度较高，橡胶相与树脂相呈“海-岛”结构；撕裂模式下EVA/CR TPV的单轴循环测试中表现出明显的Mullins效应，增大应变时，其最大撕裂强度、瞬时残余应变、内耗值和阻尼因子均增加，但应力软化因子趋于下降；随着热处理温度的上升，Mullins效应的可逆回复效果获得改善，且温度为70℃时其可逆回复行为最好。

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

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 ℃.