Abstract: Polyacrylamide grafted poly（vinyl alcohol）/polyvinylpyrrolidone semi-interpenetrating network hydrogels（PAAm-g-PEG/PVP）were designed and prepared via a simple free radical polymerization route initiated by a PEG-(NH4)2Ce(NO3)6 redox reaction technique. The swelling，and diffusion behavior as well as swelling kinetics were examined in various pH buffer solutions，and the structure and thermal properties were analyzed by Fourier transfer infrared spectra and thermal analysis system. The experimental results showed that the swelling ratios and diffusion mode of the PAAm-g-PEG/PVP hydrogels depended on the pH value of buffer solutions. The equilibrium swelling values were reduced with the increasing of pH values，which agreed with maximal theoretical water contents S∞ fitted by swelling kinetic data. The swelling behavior of the PAAm-g-PEG/PVP hydrogels might be controlled and modulated by PEG with different molecular weights.

Key words: hydrogels, polyvinylpyrrolidone, pH sensitive hydrogels, swelling behavior

摘要： 采用硝酸铈胺-聚乙二醇为氧化-还原引发体系，N,N-亚甲基双丙烯酰（N,N-MBA）为交联剂，通过简单的自由基聚合法，设计合成了一种聚（丙烯酰胺-g-聚乙二醇）/聚乙烯吡咯烷酮PAAm-g-PEG/PVP接枝交联结构的半互穿网络水凝胶。研究了它们在不同pH值缓冲溶液中的溶胀与扩散行为以及溶胀动力学；并采用红外光谱和热分析系统对其结构和热性能进行了分析测量。实验结果表明：水凝胶的溶胀行为和扩散模式取决于溶液的pH值。随着缓冲溶液pH值增加，平衡溶胀率减小；在不同的缓冲溶液中理论最大吸水量S∞与实验值基本相一致。水凝胶的溶胀行为可以通过选择加入不同分子量大小的PEG来调节和控制。

关键词: 水凝胶, 聚乙烯吡咯烷酮, pH 敏感水凝胶, 溶胀行为