基于离子超分子网络设计的室温高自修复效率天然橡胶

Design of room temperature high self-healing efficiency natural rubber based on ionic supramolecular network

将山梨酸与氧化锌按照摩尔比2/1在引发剂过氧化二异丙苯的作用下与天然橡胶(NR)共混,部分山梨酸与氧化锌原位生成的山梨酸锌(ZDS)接枝到NR基质上,使得自由的锌离子起到交联点的作用,形成离子簇,与相容性较好的NR分子链之间产生可逆的离子超分子网络,从而具备了室温下自修复的特征。研究结果表明,在NR/ZDS试样中,随着ZDS用量的增加,NR的离子交联密度先增大后减小,自修复性能逐渐下降,拉伸强度增大;ZDS超过30份(质量)时NR开始出现共价交联,自修复效率明显下降;ZDS为30份时NR的自修复效率可达99%,拉伸强度为0.78 MPa,综合性能最好。

The introduction of ion association is one of the most effective approaches to achieve the self-healing behavior of rubber.However,most commercially available rubbers are non-polar rubbers and do not have functional groups available for conversion to ionic groups.In this paper,natural rubber material that can repair itself without external interfe-rence at room temperature was prepared by introduced a reversible ionic crosslinking network.In the current work,the in situ reaction of sorbic acid(SA)with excess ZnO has been realized in natural rubber(NR).Allowed the in situ polymerization of SA/ZnO,ionic crosslinking in NR matrix were obtained by limiting the covalent crosslinking of NR molecules.Specifically,the SA with excess ZnO are blended with NR in a molar ratio of 2/1 under the action of the initiator dicumyl peroxide.