Huang Jing, Zhang Lijie, Tang Zhenghai, Wu Siwu, Ning Nanying, Sun Haibin, Guo Baochun
Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou, 510640, P. R. China.
State Key Laboratory of Organic/Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Macromol Rapid Commun. 2017 Apr;38(7). doi: 10.1002/marc.201600678. Epub 2017 Feb 15.
It is a significant but challenging task to simultaneously reinforce and functionalize diene rubbers. Inspired by "sacrificial bonds", the authors engineer sacrificial hydrogen bonds formed by pendent urazole groups in crosslinked solution-polymerized styrene butadiene rubber (SSBR) via triazolinedione click chemistry. This post-crosslinking modification reveals the effects of the sacrificial bonds based on a consistent covalent network. The "cage effect" of the pre-crosslinked network facilitates the heterogeneous distribution of urazole groups, leading to the formation of hydrogen-bonded multiplets. These multiplets further aggregate into clusters with vicinal trapped polymer segments that form microphase separation from the SSBR matrix with a low content of urazole groups. The clusters based on hydrogen bonds, serving as sacrificial bonds, promote energy dissipation, significantly improving the mechanical properties of the modified SSBR, and enable an additional wide transition temperature region above room temperature, which endows the modified SSBR with promising triple-shape memory behavior.
同时增强二烯橡胶并使其功能化是一项意义重大但具有挑战性的任务。受“牺牲键”启发，作者通过三唑啉二酮点击化学方法，在交联的溶液聚合丁苯橡胶（SSBR）中设计了由侧基四氮唑酮基团形成的牺牲氢键。这种后交联改性揭示了基于一致共价网络的牺牲键的作用。预交联网络的“笼效应”促进了四氮唑酮基团的非均相分布，导致形成氢键多重体。这些多重体进一步聚集成簇，与相邻的被困聚合物链段形成微相分离，与低含量四氮唑酮基团的SSBR基体分离。基于氢键的簇作为牺牲键，促进能量耗散，显著改善改性SSBR的力学性能，并在室温以上实现额外的宽转变温度区域，赋予改性SSBR具有前景的三重形状记忆行为。
