摘要
在5种不同温度下聚合交联,制备了一系列温度和pH双重敏感性聚(N-异丙基丙烯酰胺-co-衣康酸)水凝胶。实验发现,15、25℃得到的凝胶是透明的,45、55℃得到的凝胶是白色不透明的,而在相转变温度附近(35℃)得到的凝胶则是半透明的。FTIR测定表明,它们具有相似的化学组成和结构。SEM观察证实,它们具有不同的表面形态。测定了不同温度和pH下达到平衡时水凝胶的溶胀比,考察了水凝胶在水和强酸性溶液中的去溶胀动力学。结果表明,与15℃或25℃制备的水凝胶相比,45℃和55℃制备的水凝胶的性能有显著提高:(1)溶胀比大为增加。15℃或25℃制备的水凝胶在25℃时溶胀比分别为65.3和68.1,而45℃和55℃制备的水凝胶此时溶胀比分别高达105.7和110.1;(2)45℃和55℃制备的水凝胶在极端环境下对温度的变化仍具有较快的响应速率。例如在温度为60℃,pH=1.67的强酸条件下,45℃和55℃制备的水凝胶在60 min内皆可失去95%的水,而15℃或25℃制备的水凝胶在120 min内只能失去42%左右的水。
A series of temperature and pH dual responsive P （N-isopropylacrylamide-co-itaconic） hydrogels were prepared at five different temperatures. It was found that the gels prepared at 15 ℃ and 25 ℃ were transparent, gels prepared at 45 ℃ and 55 ℃ were opaque, while gels prepared near the phase transition temperature（35 ℃ ） were semi-translucent. The chemical compositions and structures of these hydrogels were similar to each other, as measured by FI＇IR. The surface morphologies of these hydrogels were quite different, as observed by SEM. The equilibrium swelling ratios of the hydrogels were measured at different temperatures and pH values. Furthermore, the deswelling kinetics of the hydrogels was also studied in distilled water and strong acid media. The result indicated that in comparison with gels prepared at 15 ℃ and 25 ℃, the hydrogels prepared at 45 ℃ and 55 ℃ had following improved properties. （ 1 ） Higher swelling ratios. At 25 ℃, the equilibrium swelling ratios of gels prepared at 15 ℃ and 25 ℃ were 65.3 and 68, 3 ,whereas those of gels prepared at 45 ℃ and 55 ℃ were as high as 105.7 and 110. 1 respectively. （2）Gels prepared at 45 ℃ and 55 ℃ still exhibited fast deswelling behaviors even at extreme conditions, for example, at 60 % in pH 1, 67 buffers,hydrogels prepared at 45 ℃ and 55 ℃ lost 95% water within 60 min,whereas gels prepared at 45 ℃ and 55 ℃ lost only about 42% water in 120 min.
出处
《精细化工》
CAS
CSCD
北大核心
2008年第6期545-549,557,共6页
Fine Chemicals
基金
中国科学院“百人计划”资助项目~~
