Chen Chunkun, Liu Xiangyang, Wang Jiangtao, Guo Haoran, Chen Yingjun, Wang Ningfei
School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China.
Polymers (Basel). 2024 Aug 31;16(17):2486. doi: 10.3390/polym16172486.
Polyvinyl alcohol (PVA) hydrogels find applications in various fields, including machinery and tissue engineering, owing to their exceptional mechanical properties. However, the mechanical properties of PVA hydrogels are subject to alteration due to environmental factors such as temperature, affecting their prolonged utilization. To enhance their lifespan, it is crucial to investigate their aging mechanisms. Using physically cross-linked PVA hydrogels, this study involved high-temperature accelerated aging tests at 60 °C for 80 d and their performance was analyzed through macroscopic mechanics, microscopic morphology, and microanalysis tests. The findings revealed three aging stages, namely, a reduction in free water, a reduction in bound water, and the depletion of bound water, corresponding to volume shrinkage, decreased elongation, and a "tough-brittle" transition. The microscopic aging mechanism was influenced by intermolecular chain spacing, intermolecular hydrogen bonds, and the plasticizing effect of water. In particular, the loss of bound water predominantly affected the lifespan of PVA hydrogel structural components. These findings provide a reference for assessing and improving the lifespan of PVA hydrogels.
聚乙烯醇（PVA）水凝胶因其优异的机械性能而在包括机械和组织工程在内的各个领域得到应用。然而，PVA水凝胶的机械性能会因温度等环境因素而发生变化，影响其长期使用。为了延长其使用寿命，研究其老化机制至关重要。本研究使用物理交联的PVA水凝胶，在60℃下进行了80天的高温加速老化试验，并通过宏观力学、微观形态和微观分析测试对其性能进行了分析。研究结果揭示了三个老化阶段，即自由水减少、结合水减少和结合水耗尽，分别对应体积收缩、伸长率降低和“韧脆”转变。微观老化机制受分子链间距、分子间氢键和水的增塑作用影响。特别是，结合水的损失对PVA水凝胶结构部件的寿命影响最大。这些发现为评估和提高PVA水凝胶的使用寿命提供了参考。
