采用自由基溶液聚合法,在不同温度下制备了N-异丙基丙烯酰胺(NIPAAm)与N-羟甲基丙烯酰胺(NHMAAm)的共聚物P(NIPAAm-co-NHMAAm)温敏水凝胶,并对其温敏性、溶胀动力学及其快速响应行为进行了研究。结果表明,共聚单体NHMAAm的添加量以及合成温度对凝胶的温敏响应性均有较大影响,NHMAAm摩尔分数小于15%时,共聚水凝胶具有明显的温敏性,其低临界溶液温度LCST随着NHMAAm含量的增加而提高;在60℃(高于共聚凝胶的LCST)制备的凝胶,快速响应性好,凝胶在4~8h内达到溶胀平衡,5min内能达到退溶胀平衡,失水率达到80%左右,且具有稳定的反复溶胀性。
Free-radical co-polymerization of N-isopropyl acrylamide(NIPAAm) and N-hydroxymethyl acrylamide(NHMAAm) at 60℃ and 25℃ has been employed to prepare thermo-sensitive poly(NIPAAm-co-NHMAAm) hydrogels.The thermo-sensitive behavior and the swelling and deswelling behavior of the hydrogels have been investigated.The results showed that the amount of NHMAAm in the hydrogel and the synthesis temperature both played an important role in the properties of the hydrogel.The lower critical solution temperature(LCST) of the hydrogel increased with increasing molar ratio of NHMAAm.The hydrogels prepared at 60℃ demonstrated faster response rates when the temperature was increased.The hydrogel swelled quickly within 4-8h,and shrank quickly to balance within 5min,with the water loss being about 80%.They also showed stable swelling and deswelling behavior when the temperature was switched between 25℃ and 60℃,which could be repeated over many cycles.