基于动态共价键的pH响应自修复水凝胶制备与评价

以α-甲基丙烯酸、2-丙烯酰胺-2-甲基丙磺酸共聚产物和聚乙烯醇为单体，十水合四硼酸钠为交联剂合成P(MAA /AMPS)-PVA二重互穿网络的pH响应水凝胶；通过扫描电子显微镜(SEM)、红外光谱(FTIR)、凝胶渗透色谱（GPC）、热重分析(DSC-TG)和流变仪等表征了水凝胶的表面形貌和化学状态；测定了水凝胶的溶胀性﹑pH响应性﹑自修复性和流变性。结果表明，水凝胶形成稳定的IPN互穿网络结构且该水凝胶具pH敏感性、自修复性；PVA羟基与硼酸根离子形成的共价配位硼酸酯键决定水凝胶自修复性并受到介质酸碱控制；力学性能测定结果显示，自修复水凝胶拉伸强度668 kPa,断裂伸长率可达665%，修复效率可达81%。

Synthesis and characterization of self-healing pH-sensitive hydrogel based on dynamic covalent bond

In this paper, Methacrylic acid(MAA), 2-Acrylamido-2- Methyl Propanesulfonic Acid(AMPS), polyvinyl alcohol (PVA) as monomer and Sodium Borate as crosslinking agent, semi-interpenetrating (semi-IPN) hydrogels P(MAA/PAMPS)-PVA/ was prepared. The surface morphology and chemical state of hydrogels were characterized by scanning electron microscope (SEM), fourier transform infrared spectrum (FT-IR), gel permeation chromatography(GPC), thermogravimetric analysis (DSC-TG) and rheometer; The swelling behavior, pH-sensitive, self-healing were investigated. The test results showed that the hydrogels formed a stable IPN interpenetrating network structure and exhibited pH sensitivity, self-healing. Borate ester bond formed by PVA hydroxyl group and borate ion determines self-healing which is controlled by pH of the medium. The mechanical experiment indicated that the tensile strength of the self-healing hydrogel was 668 kPa, the elongation at break was 665%, and the self-healing efficiency was 81%.