高强度耐溶胀仿软骨PVA/CS水凝胶的合成及性能

Fabrication and properties of tough and anti-swelling polyvinyl alcohol/chitosan composite hydrogels

利用冻融循环并浸泡柠檬酸钠的方法,制备了聚乙烯醇/壳聚糖(PVA/CS)复合水凝胶。通过FTIR、XRD,DSC和SEM表征了其结构和形貌,并测试了其机械性能。结果表明,PVA单网络水凝胶网孔尺寸在1.5~8.2μm,自由水含量为76.2%,有效交联密度为0.0288 mol/L,抗拉和抗压强度仅为0.2和1.4 MPa。而复合水凝胶由于氢键与离子键的协同交联作用,其网孔尺寸和自由水含量分别降低至1.5μm和1.4%,有效交联密度提高至0.4210 mol/L,抗拉和抗压强度分别为9.3和16.6 MPa。同时,该水凝胶还具有优异的抗疲劳与耐溶胀特性,连续压缩10次后水凝胶的抗压强度和韧性分别为初始值的88.1%和84.3%,在去离子水中溶胀平衡后的抗拉强度高达4.3 MPa。

Polyvinyl alcohol/chitosan(PVA/CS) composite hydrogels were prepared by freeze-thaw and soaking sodium citrate(Na3 Cit) aqueous solution. The structures and morphologies were characterized by FTIR, XRD, DSC and SEM, and the mechanical properties were tested. The results showed that PVA single network hydrogel had a mesh size between 1.5 and 8.2 μm, free water content(FW) of 76.2% and effective cross-linking density(v0) of 0.0288 mol/L. The tensile strength and compressive strength were only 0.2 and 1.4 MPa. After introducing CS into PVA single network and soaking Na3 Cit, the mesh size and FW of the prepared PVA/CS composite hydrogel decreased to 1.5 μm and 1.4%, and the v0 increased to 0.4210 mol/L. While the tensile strength and compressive strength were 9.3 and 16.6 MPa, respectively. This was attributed to the synergistic cross-linking of hydrogen bonds and ionic bonds of composite hydrogels. At the same time, the composite hydrogel exhibited excellent anti-fatigue and swelling-resistant properties. The compressive strength and toughness of the composite hydrogel after 10 successive compression tests were 88.1% and 84.3% of their original values. Furthermore, the tensile strength after reaching a swell-equilibrium in deionized water was 4.3 MPa.