Abstract: The high concentration of poly(vinyl alcohol) hydrogels possesses self-healing property. However,its self-healing mechanism and the effects of the preparation conditions on the self-healing property of the hydrogel were rarely studied. In this paper,the high concentration PVA hydrogel was prepared by the freezing and thawing method. The optimum conditions were obtained by changing the preparation conditions(the PVA molecular weight,PVA concentration,freezing time,thawing time,numbers of freezing and thawing cycles,healing time,freezing temperature,etc.) and the self-healing mechanism was analyzed. The multiple self-healing performance of the hydrogel was also investigated. The results showed that the larger the molecular weight of the PVA,the better the self-healing performance of the hydrogels. The hydrogels prepared under 2h freezing and 1h thawing in only one cycle showed the best self-healing performance,and the best healing time was 12h. The PVA hydrogel could self-heal for many times. The self-healing property of the hydrogel was due to the interaction of reversible hydrogen bond,which was mainly influenced by the content of hydroxyl group and the mobility of the PVA molecules in the hydrogel.

Key words: poly(vingl alcohol)(PVA), self-healing, hydrogels, preparation, mechanism

摘要： 高浓度聚乙烯醇（PVA）水凝胶具有一定的修复功能，但其自修复机理及制备工艺参数对其修复性能的影响缺乏研究。本文采用冷冻-解冻法制备了高浓度自修复PVA水凝胶，通过调整PVA水凝胶制备工艺参数（PVA分子量、PVA浓度、冷冻时间、解冻时间、冷冻-解冻次数、修复时间、冷冻温度等）得到了最佳工艺条件，分析了水凝胶自修复机理，并研究了PVA水凝胶的多次自修复性能。研究结果表明：相对分子质量大的PVA制备的水凝胶自修复性能好；其中冷冻时间为2h，解冻时间为1h，一次冷冻-解冻循环制备得到的水凝胶自修复性能最好，最佳修复时间为12h，能较好地进行反复自修复。指出水凝胶自修复性能主要是由其内部可逆氢键的相互作用形成的，其主要影响源于冷冻-解冻处理后水凝胶内部羟基含量及PVA分子的流动性。

关键词: 聚乙烯醇, 自修复, 水凝胶, 制备, 机理