非硫硫化橡胶选择性解交联的机理研究

Traditional vulcanizates were difficult to chemical recycling. It is an important issues to efficiently reclaim vulcanizates by selective decrosslinking in materials science. In this proposal, study on recycling and mechanism of selective decrosslinkable sulfur-free vulcanized rubber was proposed. It will first begin with non-traditional vulcanization system (excluding sulfur or peroxide). By constructing sulfur-free crosslinking network, such as ester bonds, C-N bonds, and ionic bonds, chemically decrosslinkable vulcanizates could be developed. By using metal halide, organic tin, and rare earth catalyst as catalytic systems, the selective decrosslinking reaction could be proceeded. This method has an important significance and scientific value in the development of the rubber technology. The main aspects include: (1) Catalytic systems and reaction conditions of selective decrosslinking reaction on sulfur-free vulcanization; (2) Study on the mechanism and reaction kinetics of selective decrosslinking reaction; (3) Design of the recycling and processing route of reclaimed rubber. In this proposal, new design of selective decrosslinkable vulcanizates are proposed. It is believed that the development of renewable, degradable, recyclable vulcanizate has great significant both in scientifically and practically.

传统橡胶难以有效化学回收再生，如何在保护橡胶主链的前提下，高效有选择地破坏交联网络，使其恢复可塑性和粘性，发展新的化学解交联方法，实现橡胶的回收再生显得十分重要和迫切。本课题拟开展非硫硫化橡胶选择性解交联的机理研究，提出从橡胶非硫硫化体系出发，构筑如酯键、C-N键、离子键等非硫键交联网络，以金属卤化物、有机锡催化剂、稀土催化剂等作为催化体系，选择性裂解非硫键交联网络，设计和研究橡胶选择性解交联的反应路线和机理，达到橡胶回收再生目的。主要研究内容包括：（1）非硫硫化橡胶选择性解交联催化体系、反应条件的设计；（2）非硫硫化橡胶选择性解交联反应机理和反应动力学的研究；（3）非硫硫化橡胶回收再生及工艺路线的设计。本课题提出一种新的橡胶回收再生构建方法，探索非硫硫化橡胶选择性解交联方法，阐明和揭示其反应机理和技术路线，对发展可化学降解、可回收再生的橡胶材料具有重要的科研价值和实际意义。

硫磺硫化橡胶的多硫键交联网络不易解交联，这是制约废旧橡胶通过解交联回收再生的关键难题。基于此背景，本工作首先提出从非硫硫化橡胶出发，将选择性裂解交联键的方法引入到非硫硫化橡胶的解交联反应中。根据路易斯酸对非硫交联键的选择性裂解作用，以甲苯/AlCl3作为催化体系，探讨了解交联反应的最佳催化体系和反应条件，研究并揭示了非硫硫化橡胶解交联的机理。基于此，进一步阐明了再硫化胶以及并用胶的结构与力学性能关系。. 另一方面，借鉴目前广泛研究并报道的vitrimer材料特性，本工作将动态可逆共价键引入弹性体交联网络，制备出基于酯交换反应的vitrimer-like弹性体。这类弹性体材料可通过动态交换反应进行交联网络的拓扑结构重排，无需外加试剂即可高效且简易地实现其二次回收及循环利用。通过直接反应共混法制备了ZDA内部共价交联ENR和β-羟基酯界面动态交联ENR/PLA的高分子共混物。这种ENR/PLA vitrimer-like弹性体展现出良好的循环再生特性。采用溶剂蚀刻可在循环样品中发现了独特的纤维状相结构，这为高分子共混物的聚集态研究提供了新思路和新视角。