羧乙基壳聚糖/聚乙烯醇自愈水凝胶的制备及其性能

Preparation and Properties of Carboxyethyl Chitosan/Polyvinyl Alcohol Self-Healing Hydrogel

先将壳聚糖与丙烯酸进行Michael加成反应制备羧乙基壳聚糖(CEC),高碘酸钠氧化海藻酸钠制备氧化海藻酸钠(OSA),再将OSA与少量硼酸作为交联剂交联CEC与聚乙烯醇(PVA)混合液制备CEC/PVA双网络、双动态化学交联的自愈水凝胶。采用FT-IR、SEM和TGA分别对水凝胶的结构、形貌和热稳定性进行分析。结果表明,CEC/PVA水凝胶具有良好的自愈性和pH值响应。在本文实验条件下,随着交联剂溶液用量的增加,凝胶时间减小,湿态凝胶平衡含水量减小;调控环境的pH值可实现体系的凝胶-溶液转变;PVA的引入能够提高水凝胶的抗压性能与韧性。

Carboxyethyl chitosan(CEC) was prepared by Michael addition reaction of chitosan and acrylic acid. Oxidized sodium alginate(OSA) was prepared by oxidation of sodium alginate with sodium periodate, and then CEC and polyvinyl alcohol(PVA)was crosslinked with the crosslinking agents which contained OSA and a small amount of boric acid to prepare a double-network,double dynamic chemical cross-linking, self-healing CEC/PVA hydrogel. The structure, morphology and thermal stability of the hydrogel were analyzed by FT-IR, SEM and TGA, respectively. The results demonstrated that the CEC/PVA hydrogel had good self-healing and pH response. Under the experimental condition in this study, when the dosage of the crosslinking agent increased, the gelation time and the equilibrium water content of hydrogel decreased. The sol-gel transition of the system could be achieved by adjusting the pH of the environment. The introduction of PVA could improve the compressive properties and toughness of the hydrogel.