将甲基乙烯基硅橡胶(VMQ)与乙烯-辛烯共聚物(POE)进行机械共混和化学交联,制得具有热响应形状记忆特性的共交联VMQ/POE共混物,其形状记忆性能由交联、结晶、熔融所决定,其中交联程度对结晶和熔融有显著的影响。将着重分析交联剂对共混物的硫化特性以及热学、拉伸和弯曲形状记忆性能的影响规律。结果表明:添加交联剂的共混物胶料的硫化曲线呈现出焦烧、热硫化、平坦硫化等典型硫化特征,且胶料的交联速率和凝胶率均随交联剂用量增加而呈现增大的趋势。在相同的拉伸应力载荷下,随着交联剂用量的增加,共混物的最大应变值和固定率逐渐减小,而回复率先增大后减小;共混物的循环拉伸形状记忆稳定性较好,最大应变和固定率变化较小,而回复率有明显的增大。在相同的弯曲应力作用下,共混物的固定角度、回复角度、回复速度均随交联剂用量增加而呈现出增大的趋势。对比发现,当交联剂添加份数为0.5～1.0内,共混物具有较为理想的拉伸和弯曲形状记忆性能。
Co-crosslinked methyl vinyl silicone rubber/polyolefin elastomer (VMQ/POE) blends with thermos-responsive shape memory properties were obtained by mechanically blending and chemically crosslinking VMQ with POE.The shape memory properties of the VMQ/POE blends were determined by crosslinking,crystallization and melting.Among them,the degree of crosslinking had a significant effect on crystallization and melting.In this paper,the influence of crosslinking agent on the vulcanization characteristics as well as the thermal,tensile,and bending shape memory properties of the blends was analyzed emphatically.The results showed that the vulcanization curve of the blends with crosslinking agent displayed typical vulcanization characteristics,such as scorch,thermal vulcanization and flat vulcanization,and the crosslinking rate and gelation rate of the blends increased with the increase of crosslinking agent content.Under the same tensile stress load,the maximum strain value and fixed rate of the blends gradually decreased,while the recovery rate increased first and then decreased with the increase of crosslinking agent content.The blends exhibited well cyclic tensile shape memory stability.The maximum strain and fixation rate of the blends did not change obviously,while their recovery rate increased significantly.Under the same bending stress,the fixation angle,recovery angle and recovery rate of the blends all increased with the increase of crosslinking agent content.Comparatively,when crosslinking agent content was between 0.5～1.0phr,the blends had better tensile and bending shape memory performance.
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基金资助
宁波市重大任务攻关项目(2022Z097);宁波市青年科技创新领军人才项目(2023QL051)
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