pH敏感性和温敏性聚丙烯酸钠与聚N-异丙基丙烯酰胺互穿网络材料的合成及其溶胀行为的研究

Preparation and Responsive Properties of Polysodium Acrylate and Poly (N-usioriotkacrkyamide) Inter-Polymer-Net Gels

制备了对温度和pH值具有双重敏感性的PAANa/PNIPAM互穿网络(IPN)材料,测定了IPN的平衡溶胀度和在不同温度和pH中的溶胀度变化的行为。结果显示,这种材料能分别在32℃和pH为5.5发生溶胀行为的突变, 溶胀度突变范围明显高于以往文献所报道的类似材料的变化值。根据它在温度变化和pH值变化中的溶胀行为可以得知,在网络中这两种分子链是独立作用的,但是相互之间又有影响。

A novel interpenetrating polymeric network (IPN) hydrogel composed of the temperature sensitive poly (N-isopropylacrylamide) and the pH-sensitive poly (acrylic acid) was prepared by conventional radical polymerization in the solution. The IPN hydrogels with different composition were characterized for their temperature-and pH-responsive behavior in the equilibrium state and oscillatory state. The permeability of these IPNs were investigated under various pH and temperature conditions. The results showed that these hydrogels show a best swelling ratio and temperature sensitivity when it is composed of 70% PNIPAM and exhibit a combined pH-and temperature-sensitivity at a fixed temperature range of 31-32°C and a pH value of approximately 5.5. The swelling ratio decreases when the ionic strength of solution increases, and reaches a constant value with ionic strength above 0.03 mol &middot L-1. The hydrogels also show a reversible swelling behavior with the temperature above or below the LTSC and pH higher or lower than 5.5.