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为了改善水凝胶的强度,通过端丙烯酸酯基阴离子型聚氨酯(PU)与甲基丙烯酰氧乙基苄基二甲基氯化铵(MAEBDAC)的共聚交联,合成了系列两性水凝胶(简称L1—L5)。采用差式扫描量热法(DSC)分析了阴阳离子摩尔比为0.3/1(样品L1)、1/1(样品L3)和1.3/1(样品L5)的干凝胶,结果表明,两组分间相容性良好。处于等电点的样品L3中没有微孔结构,且其可冻结水含量仅为总溶胀水量的11.7％,而在样品L1和L5中均具有微孔结构且可冻结水含量增至50％。研究pH响应性表明,水凝胶的响应行为取决于凝胶中过量电荷的性质,外加电介质对样品L3的吸水能力影响较小。凝胶强度随聚氨酯链段的引入而提高。
In order to improve the strength of hydrogels, a series of amphoteric hydrogels were synthesized by the copolymerization cross-linking of terminal acrylate-based anionic polyurethanes (PUs) and methacryloyloxyethylbenzyldimethylammonium chloride (MAEBDAC) (Referred to as L1-L5). Dry xerogels were analyzed by differential scanning calorimetry (DSC) with molar ratios of anion to cation of 0.3 / 1 (sample L1), 1/1 (sample L3) and 1.3 / 1 (sample L5). The results showed that two groups Good compatibility between points. Sample L3 at the isoelectric point had no microporous structure, and its freezable water content was only 11.7% of the total amount of water swelling, while it had a microporous structure in both of samples L1 and L5 and the content of freezable water increased to 50%. The study of pH responsiveness shows that the hydrogel’s response behavior depends on the nature of the excess charge in the gel, with the addition of dielectric having little effect on the water uptake capacity of sample L3. The gel strength increases with the introduction of polyurethane segments.