羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶的制备及溶胀性能研究

Preparation and Performance Characterization of pH/Temperature-sensitive Carboxymethylchitosan/Poly(N-isopropylacrylamide) Semi-IPN Hydrogels

制备了具有温度、pH值双重敏感特性的羧甲基壳聚糖/聚(N异丙基丙烯酰胺)的半互穿网络水凝胶(CMCS/PNIPAAm semi-IPN)。研究了温度及pH值对该凝胶溶胀度的影响。结果表明,在强酸(pH值为1.0,2.71)、弱碱(pH值为7.4)和强碱的条件下,semi-IPN凝胶溶胀度均随着温度的升高而下降直至达到平衡状态。经pH值为2.71缓冲溶液浸泡处理的凝胶的相转变温度有明显的降低。该凝胶的消溶胀速率随着凝胶中CMCS组分含量的增加而增大。这些现象主要与水凝胶本身的微观结构以及所加入的羧甲基壳聚糖基团结构有关。

A new kind of the semi-IPN hydrogels based on linear carboxymethyl chitosan （CMCS） ana cross-linked Poly （N-isopropylacrylamide） （PNIPPAAm）, which exhibited pH and temperature sensitivities, was synthesized. The effect of temperature and pH value on the swelling ratio（SR） of semi-IPN hydrogels was investigated in details. The result indicated that at acidic （pH 值为 1.0,2.71）, weak alkaline （pH 值为 7.4） and strong alkaline （pH 值为9.18） conditions, the SR of the semi-IPN hydrogels decreased with increasing temperature until reaching the equilibrium state. It is notable that the volume phase transmission temperature （VPTT） of the hydrogels was significantly reduced at pH 值为 2.71. In addition, the deswelling rate increases with increasing CMC content in the semi-IPN hydrogel at a temperature over the VPTT （45 ℃）.