The effect of drying on the viscoelastic, tensile behavior of a dual cross-linked poly(vinyl alcohol)(PVA) hydrogel is studied experimentally. This gel contains about 90% water when fully hydrated and is highly stretchable. Using a microbalance with a density kit it is found that as the gel dries its volume shrinks in linear proportion to the mass. The impact of drying on the gel’s mechanical properties is measured in uniaxial tension tests, which include loading–unloading tests at three different stretch rates, a complex loading history test consisting of two different loading segments and a stress-relaxation test. The resulting data show that the gel becomes much stiffer as the gel dries and that drier gels do not fully recover upon unloading. The viscoelastic response from specimens with different hydration levels can be described by a previously developed constitutive model of the gel. The results show that the constitutive model parameters are strongly dependent on hydration level.

通过实验研究了干燥对双交联聚乙烯醇 (PVA) 水凝胶的粘弹性、拉伸行为的影响。这种凝胶在完全水合时含有约 90% 的水，并且具有高度可拉伸性。使用带有密度套件的微量天平发现，随着凝胶干燥，其体积与质量成线性比例缩小。干燥对凝胶机械性能的影响在单轴拉伸试验中测量，包括在三种不同拉伸速率下的加载-卸载试验、由两个不同加载段组成的复杂加载历史测试和应力松弛试验。结果数据表明，随着凝胶变干，凝胶变得更加坚硬，并且在卸载时干燥的凝胶不会完全恢复。具有不同水合水平的样品的粘弹性响应可以通过先前开发的凝胶本构模型来描述。结果表明，本构模型参数强烈依赖于水化水平。