基于可交换硅醚化学的橡胶网络设计和性能

Although significant effort has been devoted to introduce dynamic covalent bonds into cross-linked polymer materials, however, the cross-linking of rubber materials, a typical category of thermosets, is still lacking of high-efficient and universal strategies based on dynamic covalent chemistry. Furthermore, the correlations between network topology and reprocessability of rubber materials with dynamic covalent networks is of great importance but rarely explored. In this proposal, reactive moieties of silyl ether linkages are introduced between rubber chains and cross-linkers for the implementation of silyl ether exchange chemistry into the cross-linked network of diene rubbers. By virtue of the dynamic nature of silyl ether-based networks, rubber materials with plasticity and reprocessability are prepared. The main research aspects include: (1) Structure design and implementation of exchangeable silyl ether-based networks into diene rubber materials; (2) Expositing the mechanism and influence factors of silyl ether cross-linking and exchange reactions; (3) Evaluation of structure-performance correlations between network topology and reprocessability of the resultant rubber materials. In this proposal, the implementation of dynamic covalent networks afforded by silyl ether exchange chemistry provides a brand-new avenue to translate plasticity and reprocessability into rubbers materials. Due to the prominent designability of silyl ether-based networks, the present universal strategy can facilely tune the network topology, which opens doors to rationalize the overall performance of resultant materials and also provide a novel methodology to afford evaluation and optimization of reprocessability of other vitrimers. Hence, the current proposal is convinced of great scientific and practical significance.

虽然动态共价键交联高分子的研究已取得了长足进展，但橡胶作为典型的交联高分子，依然缺乏高效和普适性的动态共价交联策略，而且人们对网络拓扑结构与橡胶再加工性能的关系不甚了了。本项目提出硅醚可交换键交联二烯烃橡胶的研究，通过在橡胶和交联剂间引入硅醚化反应性基团，将硅醚可交换化学植入橡胶交联网络中，制备具有可塑再加工性的交联橡胶材料。主要研究内容包括：（1）二烯烃橡胶材料中硅醚可交换交联网络的设计与构筑；（2）硅醚化交联和交换反应的机理与影响因素的研究；（3）硅醚交联橡胶的网络拓扑结构与再加工性能间的构-效关系研究。本项目提出了橡胶交联网络中引入可交换硅醚化学的新思路，为可塑再加工橡胶材料的设计制备提供了新策略。由于硅醚可交换网络的可设计性强，可简便地调节橡胶网络拓扑结构，不仅为调控材料性能提供新的途径，也为类玻璃高分子再加工性能评估和优化提供新的理论基础，具有重要的科学意义和现实意义。

动态硅醚键交联网络具有结构可设计性强的特点，可简便地调节网络结构来赋予材料预期的宏观性能。本项目提出烯烃橡胶中动态硅醚键交联网络的设计构筑及性能调控的研究，通过在交联剂中引入硅醚、或在橡胶和交联剂间引入可硅醚化的反应性基团，制备具有可塑再加工性的交联橡胶材料。主要研究内容包括：（1）发展了几种硅醚交联橡胶网络的构筑及增强方法，实现商品化橡胶中硅醚交联网络的可控构筑及高效强韧化。揭示了硅醚化交联及交换反应影响因素及其作用机制，建立了硅醚交联网络拓扑结构与材料性能间的构-效关系并探索其潜在应用前景；（2）开发了基于交联剂官能度或交联均匀性调控的动态共价交联网络的高温松弛特性可控调节方法，实现动态键交联橡胶材料的可重复挤出加工，揭示其网络松弛行为的影响因素及其作用机制；（3）提出了基于动态硼硅酸酯交联网络的可塑加工橡胶材料制备方法。揭示了硼硅酸酯交联及交换反应、交联网络物理机械、网络松弛蠕变及可重复加工等性能的影响规律。本项目提出了硅醚交联橡胶网络的可控构筑及网络松弛特性调控的新方法，为实现动态键交联橡胶材料的高性能化及连续回收加工提供了全新的思路，具有重要的科学意义和现实意义。