【作者】 张黎明； 王轶； 朱斯亮；

【Author】 Li-Ming Zhang, Yi Wang, Si-Liang Zhu Institute of Polymer Science, Zhongshan (Sun Yat-sen) University, Guangzhou 510275, China

【机构】 中山大学高分子研究所；

【摘要】 <正> 致力于结构更新、效能更高的新型聚电解质类凝胶材料的研究,最近我们采用自由基聚合交联原位复合法,以过硫酸钾为引发剂、N,N’-亚甲基双丙烯酰胺为交联剂,在水溶液中制备了基于聚(丙烯酸-co-磺酸甜菜碱两性单体)与亲水性Laponite粘土的纳米复合型聚电解质水凝胶。为研究所得纳米复合水凝胶的水溶胀行为,详细考察了时间、温度、pH值和外加盐浓度对凝胶溶胀性能的影响。与仅显示pH敏感性的单一聚丙烯酸凝胶不同,引入磺酸甜菜碱两性更多还原

【Abstract】 Crosslinked polyelectrolyte hydrogels loaded with dispersed clays are a new class of composite materials which combine elasticity and permeability of the hydrogels with good water absorption and swelling of the clays as well as their high ability to absorb different substances. In this work, novel polyelectrolyte-based nanocomposite hydrogels, based on poly(acrylic acid-co-sulfobetaine amphoteric monomer) and hydrophilic laponite clay, were synthesized by K2S2O8-initiated free radical in-situ polymerization in the presence of N,N’ -methylene bis acrylamide (MBA) as the crosslinking agent.To study the swelling behavior of the nanocomposite hydrogels in water, the effects of time, temperature, pH and the concentration of added salts on the swelling property were investigated. Different from individual polyacrylic acid hydrogel with only pH sensitivity, the hydrogels incorporating the sulfobetaine amphoteric monomer are characteristic of both pH and salt sensitivity. In the saline solution, the swelling ratio of the hydrogels containing the sulfobetaine amphoteric monomer increases with the increase of salt concentration, showing obvious "anti-polyelectrolyte swelling behavior" . In comparison with pure polyelectrolyte hydrogel, the nanocomposite hydrogels containing the clay have the improved swelling ability and enhanced stimuli response. The study on the swelling kinetics of the hydrogels shows that the transport of water in the hydrogels belongs to non-Fick diffusion under concerned conditions.In addition, differential scanning calorimetry (DSC) was used to probe the states of water in the nanocomposite hydrogels. Three types of water, including freezing water, non-freezing water and freezing bound water, were found. The effect of the structural change in the hydrogel, especially the amount of incorporated clay, on the water states was investigated.更多还原