单宁基pH敏感水凝胶的制备及其对生物碱的吸附性能研究

pH-sensitive hydrogels have been applied in medicine, chemical industry and environmental protection,and many other fields. In this project, a kind of hydrophilic polymer used as crosslinker is synthesized by the copolymerization of allylglycidyl ether and hydrophilic vinyl monomer, pH-sensitive hydrogels are prepared from vegetable tannin by the ring-opening reaction that the epoxy groups in the hydrophilic polymer reacted with the phenolic hydroxyl groups in tannin.The polyphenol structure of vegetable tannin is introduced into the hydrogel network, and the selective adsorption properties of the hydrogel for alkaloids will be improved by the hydrogen bonding interactions between alkaloid and phenol hydroxy of vegetable tannin. The mechanism of the response of the hydrogel on pH is revealed by investigating the microscopic structure and phase transition behavior of the hydrogel, and studying the relationship between the structure and swelling properties of the hydrogel; the skeletal structure and functional groups of the hydrogel are regulated by the design of the network structure of the hydrogel,the adsorption mechanism of the hydrogel for alkaloids is clarified by studying the relationship of the chemical structure and crosslinked network of the hydrogel with the adsorption and desorption properties of the hydrogel, which will provide a theoretical basis for the applications of the material in the field of separation and purification of natural products. This project provides a new method for the preparation of tannin-based polymer material, which will have positive significance for the development of new biomass-based polymer materials and the realization of high-value utilization of tannin.

pH敏感水凝胶在医药、化工和环保等领域具有广泛的应用。本项目以植物单宁为原料，丙烯基缩水甘油醚和亲水的乙烯基单体共聚合成的亲水聚合物为交联剂，通过单宁分子结构中的酚羟基与共聚物分子链上的环氧基团开环交联制备pH敏感水凝胶。将植物单宁的多酚结构引入水凝胶网络中，利用植物单宁的酚羟基与生物碱的氢键作用以提高水凝胶对生物碱的选择性吸附性能。通过对水凝胶的微观结构和相变行为的考察，研究水凝胶的结构与溶胀性能的关系，揭示水凝胶对pH的响应机制；通过对水凝胶的网络结构的设计，调控水凝胶的骨架结构和功能基团，研究水凝胶的化学结构、交联网络与水凝胶对生物碱的吸附、脱附性能的关系，阐明水凝胶对生物碱的吸附机理，为实现该材料在天然产物分离纯化领域的应用提供理论依据。本研究提供一种制备单宁基高分子材料的新方法，对于开发新型生物质基高分子材料，实现单宁的高值化利用，具有积极意义。

利用可再生的生物质开发生产可降解性的高分子材料，实现生物质原料在高分子材料领域对石油原料的有效替代，对于缓解能源危机、保护环境，具有重要意义。本项目以单宁、间苯二酚为原料，多聚甲醛为交联剂，制备间苯二酚-单宁酚醛树脂，探讨了其对咖啡因的吸附性能，由于间苯二酚的扩链作用，增大了树脂网络空间结构，有利于咖啡因分子的渗透，改善树脂对咖啡因的吸附性能；以单宁酸为原料，丙烯基缩水甘油醚与亲水的乙烯基单体共聚合成带环氧基团的亲水性大分子为交联剂，单宁酸的酚羟基与交联剂分子链上的环氧基团开环交联制备单宁基水凝胶，通过凝胶网络中单宁酚羟基的离解程度随外界环境pH 的改变而实现水凝胶对pH 敏感性；以单宁与多聚甲醛缩合制备单宁基酚醛大分子，再以环氧氯丙烷为交联剂将单宁基酚醛大分子与羧甲基纤维素钠交联制备了羧甲基纤维素-单宁基吸附树脂，将单宁引入羧甲基纤维素侧链，通过羧甲基纤维素的羧基与单宁的酚羟基的协同作用改善树脂对亚甲基蓝的吸附性能。本项目研究提供制备单宁基高分子材料的新方法，对于开发新型生物质基高分子材料，实现单宁的高值化利用，具有积极意义。