Yu Shuangjian, Wu Siwu, Zhang Chengfeng, Tang Zhenghai, Luo Yanlong, Guo Baochun, Zhang Liqun
Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640, China.
College of Science, Nanjing Forestry University, Nanjing 210037, China.
ACS Macro Lett. 2020 Aug 18;9(8):1143-1148. doi: 10.1021/acsmacrolett.0c00527. Epub 2020 Jul 27.
Due to the exchangeability of dynamic covalent bonds in the covalent adaptable networks (CANs) at elevated temperature, they possess recyclability while still maintaining many of the superior properties of thermosets. The exploration of dynamic covalent chemistry is of great significance to the expansion of CANs library and hence the sustainable development of thermosets. In this work, we discovered that, in absence of catalyst, the direct metathesis of the cyclic acetals proceeds while the acyclic acetals cannot. The metathesis kinetics of the cyclic acetals were fully revealed with model compounds. For the CANs demonstration, a series of cross-linked spirocyclic acetal polymers with excellent reprocessability, high thermal stability, and high refractivity were prepared via thiol-ene click polymerization. We envisage that the uncovering of the catalyst-free metathesis of cyclic acetals will enrich the dynamic chemistry of acetals and greatly promote the development of acetal-based CANs and their potential applications in optical devices.
由于共价自适应网络（CANs）中的动态共价键在高温下具有可交换性，它们具有可回收性，同时仍保留热固性材料的许多优异性能。探索动态共价化学对于扩展CANs库以及热固性材料的可持续发展具有重要意义。在这项工作中，我们发现，在没有催化剂的情况下，环状缩醛会发生直接复分解反应，而非环状缩醛则不会。通过模型化合物全面揭示了环状缩醛的复分解动力学。为了展示CANs，通过硫醇-烯点击聚合制备了一系列具有优异再加工性、高热稳定性和高折射率 的交联螺环缩醛聚合物。我们设想，环状缩醛无催化剂复分解反应的发现将丰富缩醛的动态化学，并极大地促进基于缩醛的CANs的发展及其在光学器件中的潜在应用。
