EVA/NBR TPV压缩Mullins效应的研究

Study on Compression Mullins Effect of EVA/NBR TPV

采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),系统研究了EVA/NBR TPV压缩Mullins效应。结果表明,随着EVA/NBR共混比及压缩应变的增大,TPV压缩Mullins行为趋于显著;当压缩应变一定时,首次循环加载-卸载过程中最大压缩应力、内耗和tanδ均达到最大值,而第2次加载-卸载过程中均发生大幅下降,之后下降趋势逐渐减弱。在相同应变下,EVA/NBR共混比60/40的TPV最大压缩应力、残余变形、内耗、应力软化因子和tanδ均大于共混比40/60的TPV,变化幅度较为明显。

Ethylene-vinyl acetate copolymer(EVA)/nitrile rubber(NBR)thermoplastic vulcanizate(TPV)was prepared by dynamic vulcanization method,and the EVA/NBR TPV compression Mullins effect was systematically studied.The results showed that with the increase of EVA/NBR blending ratio and compression strain,the compression Mullins effect of TPV was more obvious.When the compression strain was constant,the compression stress,internal friction and tanδreached the maximum during the first cyclic loading-unloading process,while it decreased significantly during the second loading-unloading process,and then the downward trend gradually weakened.Under the same strain,the maximum compression stress,residual deformation,internal friction,stress softening factor and tanδof TPV with an EVA/NBR blending ratio of 60/40 were greater than those of TPV with a blending ratio of 40/60,and the variation was obvious.