基于蓖麻油和香草醛的Vitrimer材料动态双交联网络的构建及性能调控机制

Unsaturated polyester thermosets use petrochemical resources as raw materials and are difficult to recycle at the end of service life. To tackle these problems, this proposal outlines a strategy to develop a novel unsaturated polyester Vitrimer (glass-like polymer) material from biomass-based castor oil and vanillin. By introducing reversible dynamic transesterification bonds as well as disulfide bonds, a dynamic double crosslinking network with controlled crosslinking degree will be constructed. The dynamic double crosslinking network will impart the material with excellent mechanical properties at room temperature, while the dynamic chemical bonds will allow for high melt fluidity of the material at high temperatures, thus obtaining a balance of reshaping, reprocessing, and mechanical properties of the castor oil-based thermosets. The preparation of epoxidized methacrylated castor oil (EMCO) and vanillin-based reactive diluent (RMV), the crosslinking curing behavior of the resin system, and the construction of double crosslinking networks will be systematically studied. Based on this understanding, we will clarify the influence of AMD and RMV types and loadings on the crosslinking degree of dynamic double crosslinking networks and reveal the internal linkage among dynamic chemical bond types and quantities, crosslinking degree of dynamic double crosslinking network, mechanical properties, and reshaping and reprocessing ability. Furthermore, the structure-activity relationship between the microstructure and macroscopic properties of castor oil-based unsaturated polyester materials will be established. The regulation of material properties are expected to realize, providing a theoretical basis for the high value utilization of castor oil and vanillin and sustainable recycling of unsaturated polyester thermosets.

传统不饱和聚酯材料存在以石化资源为原料和使用后难以可持续循环利用的缺陷。针对此问题，本项目拟以生物质基的蓖麻油和香草醛为原料制备新型的不饱和聚酯类玻璃高分子（Vitrimer）材料，通过引入可逆的动态酯交换键和二硫键构筑交联度可调控的动态双交联网络，借助常温下动态双交联网络优异的力学性能和高温下动态化学键的重塑流动性，实现对蓖麻油基材料重塑再加工性和力学性能的兼顾。系统研究蓖麻油双官能度单体和香草醇基活性稀释剂RMV的制备工艺、树脂体系交联固化行为、双交联网络的构建，在此基础上，阐明二元胺AMD和RMV种类和用量对动态双交联网络交联度的影响规律，揭示动态化学键种类和数量、动态双交联网络交联度、材料力学性能和重塑再加工性三者间的内在联系，建立蓖麻油基不饱和聚酯材料微观结构与宏观性能的构效关系，实现材料性能的调控，为蓖麻油的高值化利用、不饱和聚酯的可持续循环利用及改善环境问题提供理论依据。

热固性材料通常存在以石化资源为原料和使用后难以可持续循环利用的问题。本项目以生物质基蓖麻油为原料，通过“甲基丙烯酸酐酯化”和“甲酸/双氧水环氧化”两步法制备了同时含有环氧基和不饱和碳碳双键的蓖麻油基不饱和聚酯（EMCO）基体树脂，在此基础上，将4,4-二硫代二苯胺（AFD）和衣康酸（IA）单独或复配作为固化剂/交联剂制备得到含有可逆动态二硫键或和酯交换键的蓖麻油基类玻璃高分子材料，系统研究了EMCO-AFD、EMCO-IA和EMCO-AFD-IA三种蓖麻油基材料体系的使用性能（力学性能、耐溶剂性、玻璃化转变温度）和循环再利用性能（重塑再加工性、自修复性、化学降解性）。当氨基与环氧基的摩尔比为1:1时，基于二硫键制备的EMCO-AFD Vitrimer材料表现出最佳的综合性能；当羧基与环氧基的摩尔比为1:1时，基于酯交换键制备的EMCO-IA Vitrimer材料表现出最佳的循环使用性能。基于酯交换键和二硫键的EMCO-AFD-IA Vitrimer材料，当IA与AFD的摩尔比为5:5时，该Vitrimer材料具有平衡兼顾的力学性能和循环使用特性。基于此，揭示了酯交换键和二硫键种类和数量、双交联网络交联度、材料力学性能和循环再利用性之间的关系，获得了蓖麻油基不饱和聚酯Vitrimer材料微观结构与宏观性能的构效关系，实现材料性能的调控，对于推动不饱和聚酯和环氧树脂等热固性材料的循环再利用和实现双碳目标有重要意义。