本论文利用低分子量聚丙烯酸钠的盐析作用，在室温下直接通过向聚丙烯酸钠（PAAS）水溶液表面加入聚乙烯醇（PVA）水溶液的方法获得机械性能良好的物理交联PVA-PAAS水凝胶。后续对该水凝胶分别进行干燥溶胀或冷冻解冻处理，获得了力学性能进一步提升的高强度水凝胶。通过红外光谱与X射线粉末衍射，证明了水凝胶的结构组成以及氢键作用是该水凝网络交联形成的主要原因。探究了PAAS浓度、溶液静置时间及后处理对水凝胶含水量和力学性能的影响。随着PAAS浓度增加，水凝胶的力学性能得到明显提升，但含水量随之下降。干燥溶胀处理和冷冻解冻处理对较低PAAS浓度下制备的水凝胶的力学性能有明显的提升，但对高PAAS浓度下制备的水凝胶的力学性能提升作用有限。PVA质量分数固定为10%，在室温下通过质量分数为35%的PAAS水溶液直接制备得到的水凝胶的断裂强度和弹性模量分别为14.8 MPa和3.5 MPa；经过冷冻解冻处理后的水凝胶的断裂强度和弹性模量分别为16.4 MPa和5.8 MPa。由此可见，通过该方法可以有效且简便地制备出强度较高的聚乙烯醇水凝胶。

In this paper, the physical cross-linked poly(vinyl alcohol)-sodium polyacrylate (PVA-PAAS) hydrogels with good mechanical properties are prepared directly by adding PVA aqueous solution to the surface of PAAS aqueous solution at room temperature because of the salting out effect of low molecular weight sodium polyacrylate. The hydrogels are subsequently dry-swollen or freeze-thawed, respectively, to obtain a high-strength hydrogel with further improved mechanical properties. Hydrogels composition and formation mechanism are studied through infrared spectroscopy and X-ray powder diffraction and it is proved that these hydrogels are fabricated by hydrogen bonding. The effects of PAAS concentration, solution placement time and post-treatment on the water content and mechanical properties of hydrogels are also investigated. With the increase of PAAS concentration, the mechanical properties of the hydrogels are significantly improved, but the water content decreases. Dry-swelling and freeze-thawing can significantly improve the mechanical properties of hydrogels prepared at a low PAAS concentration, but have limited effects on those prepared at higher PAAS concentrations. At a fixed PVA mass fraction of 10%, the tensile strength and Young’s modulus reach 14.8 MPa and 3.5 MPa when PAAS mass fraction is 35%. Tensile strength and Young’s modulus of the hydrogel reach a maximum of 16.4 MPa and 5.8 MPa after freeze-thawing treatment. It can be seen that high strength PVA hydrogels can be effectively and simply prepared by this method.