Abstract A dual network hydrogel made up of polyvinylalcohol (PVA) crosslinked by borax and polyvinylpyrrolidone (PVP) was prepared by means of freezing-thawing circles. Here PVP was incorporated by linking with PVA to form a network structure, while the introduction of borax played the role of crosslinking PVA chains to accelerate the formation of a dual network structure in PVA/PVP composite hydrogel, thus endowing the hydrogel with high mechanical properties. The effects of both PVP and borax on the hydrogels were evaluated by comparing the two systems of PVA/PVP/borax and PVA/borax hydrogels. In the former system, adding 4.0% PVP not only increased the water content and the storage modulus but also enhanced the mechanical strength of the final hydrogel. But an overdose of PVP just as more than 4.0% tended to undermine the structure of hydrogels, and thus deteriorated hydrogels’ properties because of the weakened secondary interaction between PVP and PVA. Likewise, increasing borax could promote the gel crosslinking degree, thus making gels show a decrease in water content and swelling ratio, meanwhile shrinking the pores inside the hydrogels and finally enhancing the mechanical strength of hydrogels prominently. The developed hydrogel with high performances holds great potential for applications in biomedical and industrial fields.

中文翻译：

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硼砂作为结构形成促进剂的 PVP 改性双网络 PVA 水凝胶的高性能

摘要 采用冻融循环法制备了硼砂交联的聚乙烯醇（PVA）和聚乙烯吡咯烷酮（PVP）双网络水凝胶。这里PVP通过与PVA连接形成网络结构而被引入，而硼砂的引入起到了交联PVA链的作用，加速了PVA/PVP复合水凝胶中双重网络结构的形成，从而赋予了水凝胶较高的力学性能. 通过比较 PVA/PVP/硼砂和 PVA/硼砂水凝胶的两种体系，评估了 PVP 和硼砂对水凝胶的影响。在前者的体系中，添加 4.0% PVP 不仅增加了含水量和储能模量，而且增强了最终水凝胶的机械强度。但是过量的PVP就超过了4个。0% 倾向于破坏水凝胶的结构，从而降低水凝胶的性能，因为 PVP 和 PVA 之间的次级相互作用减弱。同样，增加硼砂可以促进凝胶的交联度，从而使凝胶的含水量和溶胀率降低，同时缩小水凝胶内部的孔隙，最终显着提高水凝胶的机械强度。开发的高性能水凝胶在生物医学和工业领域具有巨大的应用潜力。同时缩小水凝胶内部的孔隙，最终显着提高水凝胶的机械强度。开发的高性能水凝胶在生物医学和工业领域具有巨大的应用潜力。同时缩小水凝胶内部的孔隙，最终显着提高水凝胶的机械强度。开发的高性能水凝胶在生物医学和工业领域具有巨大的应用潜力。