聚乙烯醇水凝胶溶胀特性研究

在前文对聚乙烯醇水溶液冰冻凝胶化浓度依赖性研究基础上，对接触浓度（Ｃ）以上聚乙烯醇水溶液通过冰冻－融化处理，制得了一种含水率高达９５～９８％的水凝胶．系统研究了该水凝胶在蒸馏水中的溶胀及溶解特性．得到了一个与实验结果相吻合的溶胀动力学方程：Ｑ１＝Ｑｅ－（Ｑｅ－ＱＯ）／ｅｋｔ，及平衡溶胀比Ｑｅ与浓度之间的定量关系：Ｑｅ＝６０．３－４．４５×１０２Ｃ．发现当冰冻－融化次数Ｎ≤５时，平衡溶胀比Ｑｅ及溶解量Ｗ与冰冻－融化次数（Ｎ）间满足幂函数关系：Ｑｅ。Ｗ通过对聚乙烯醇水凝胶平衡溶胀比与经冰冻处理的聚乙烯醇水溶液特性粘数进行比较，发现反映链间氢键凝聚缠结效应与反映链内氢键凝聚缠结效应的定量指标具有等效性．

INVESTIGATION OF SWELLING PROPERTY OF POLY (VINYL ALCOHOL) HYDROGEL

n the basis of previous investigation of concentration dependence of cryogenic gelation for aqueous solution of poly (vinyl alcohol) (PVA), the physical hydrogels with high water content were prepared by freezing and thawing to the PVA aqueous solution. The properties of the hydrogels in distilled water have been investigated. A swelling kinetic equation was proposed:Qt= Qe-(Qe- Qo) /eldThis equation fits the experimental results. A quantitative relationship between equilibrium swelling ratio and the solution concentration was also obtained: Qe=60.3 -4.45×102C. It was found that eqinlibrium swelling ratio Qe, dissolution amount W of the hydrogels and the times N of freezing-thawing cycles followed the power laws:Qe; W, as N≤5. By comparing the results of this work with that of previous paper, we found that Qe, reflected the intermolecular hydrogen bonding cohesional entanglement of concentrated soloution of PVA and η], described the intramolecular hydrogen bonding cohesional entanglement in dilute solution of PVA are equal in value.