电子束辐照烯烃嵌段共聚物制备二重形状记忆弹性体

摘要

在真空氛围中对烯烃嵌段共聚物(OBC)进行电子束辐照.探讨了吸收剂量对OBC交联程度、力学性能、结晶和二重形状记忆效应的影响.通过应力?应变拉伸性能测试、X射线衍射(XRD)和拉伸恢复等方法对辐照样品的力学性能、晶体结构和二重形状记忆效应进行表征.结果表明:随着吸收剂量的增加, OBC凝胶含量增加,断裂伸长率逐渐降低,100%定伸强度增加,而在剂量50~150 kGy时,拉伸强度随剂量的增加而增加,在更高剂量时开始降低;XRD测试表明,交联主要发生在无定形区域,重结晶的样品晶型结构没有发生改变,高剂量下三维交联结构部分抑制可结晶聚乙烯链段的扩散和重排,从而结晶度稍微降低;拉伸恢复测试表明,在剂量50 kGy以上时,样品都有二重形状记忆效应,形状固定率和形状回复率均在93%以上.%ABSTRACT The effects of electron-beam radiation, under vacuum, on the tensile property, re-crystallized structure, and dual-shape memory effect of an olefin block copolymer (OBC) were studied through stress-strain measurements, X-ray diffraction (XRD), and observation of strain recovery. The results showed that the gel content and strength at 100% strain increased for an absorbed dose of 50~250 kGy, whereas the elongation at break decreased with the increasing absorbed doses. The tensile strength increased when the absorbed dose was 50~150 kGy and decreased at 150~250 kGy. The XRD results demonstrated that electron-beam-induced selective crosslinking in the soft segment of the OBC did not influence the recrystallized structure but that crosslinking at higher doses slightly influenced the diffusion and rearrangement of the hard segment during recrystallization. The crosslinked OBC samples exhibit outstanding melt strength and dual-shape memory effect based on the observation of strain recovery. Both the shape fixity and recovery ratio are greater than 93%.