疏水改性PNIPA水凝胶的制备及在表面活性剂溶液中的性能

SYNTHESIS OF HYDROPHOBICALLY MODIFIED HYDROGELS WITH ACRYLATES AND SWELLING BEHAVIOR OF HYDROGELS IN THE SOLUTIONS OF SURFACTANTS

采用水溶液和水溶液胶束自由基聚合方法分别制备了聚N-异丙基丙烯酰胺水凝胶(PNIPA)和疏水改性PNIPA水凝胶:聚N-异丙基丙烯酰胺-co-丙烯酸甲酯(MA)/丙烯酸乙酯(EA)/丙烯酸丁酯(BA)/丙烯酸十二酯(DA)水凝胶。研究了凝胶的微观结构及不同结构的水凝胶在表面活性剂溶液中的溶胀行为。结果表明,PNIPA与疏水改性PNIPA水凝胶有着不同的微观形态结构;与PNIPA水凝胶相比,疏水改性PNIPA水凝胶在十二烷基硫酸钠(SDS)和十六烷基三甲溴化铵(CTAB)水溶液中的溶胀率增大,温敏性增强。疏水改性水凝胶在溶液中的溶胀行为与凝胶化学结构、溶液组成有关。对于疏水改性丙烯酸酯-NIPA共聚水凝胶,其溶胀率随丙烯酸酯碳链长度的增加而降低,在SDS溶液中的相转变温度远比CTAB溶液中的高,突变温度区间更宽。

Poly-N-isopropylacrylamide (PNIPA) hydrogels and hydrophobically modified PNIAP, Poly-N-isopropylacrylamide-co-methyl acrylate/ethyl acrylate/ butyl acrylate/dodecyl arylate hydrogels, were synthesized respectively by free radical polymerization and free micellar copolymerization in aqueous solution. The microstructure of and the different swelling behaviors of hydrogels with various structures in surfactant solutions were studied. The results show that the hydrophobically modified PNIPA and PNIPA are different in microstructures, which are due to the diversity in compatibility. Moreover, the hydrophobically modified hydrogels (HMH) have greater swelling ratio and temperature sensitivity in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant cetyltrimethylammonium bromide (CTAB). The swelling behaviors of HMH relate to its chemical structure and solution components as well. With the increasing in carbon atom number of acrylate, the swelling ratio of the HMH by this paper decreases. Furthermore, the synthesized HMH have a higher transforming temperature and a wider abrupt changing interval in SDS solution than in CTAB solution.