丝胶含量对温敏凝胶形态和热性能的影响

采用半互穿网络技术制备得到不同丝胶(SS)含量的丝胶基聚(N-异丙基丙烯酰胺)水凝胶。采用XRD、SEM、DSC和TGA-DTG分别考察了水凝胶的结构、相容性和热稳定性, 以及凝胶的内部孔洞形态和体积相转变行为。结果表明: 丝胶多肽链和凝胶分子链存在微弱的氢键作用力; 随着丝胶质量分数由0增加至20%, 凝胶的内部孔径增加1~2倍, 且均呈结构完好的蜂窝状结构; 丝胶分子链均匀地分散在凝胶基体中, 无相分离发生; 丝胶分子链引入使聚(N-异丙基丙烯酰胺)水凝胶的体积相转变温度增加0.2~0.3℃; 最大热分解温度和DTG分解峰温度呈缓慢增加趋势。

Effect of silk sericin content on the mophology and thermal stability of temperature-sensitive hydrogels

The poly(N-isopropylacrylamide)(polyNIPAM) hydrogels with various silk sericin (SS) content were successfully prepared by semi-interpenetrating network(Semi-IPN) method. The structure, compatibility and thermal stability of hydrogel, including the internal pore shape and volume phase transition behavior of hydrogels, were investigated by XRD, SEM, DSC and TGA-DTG. The results show that hydrogen bond acting force can be found between silk sericin polypeptide chains and polyNIPAM molecular chains due to the existence of functional group like carboxyl group, hydroxyl group and amide group. With increasing silk sericin mass faction of silk sericin to silk sericin and N-isopropylacrylamide(NIPAM) from 0 to 20%, the interior pore size of PNIPAM hydrogel increases to two or three times and presents honeycomb patterned structure. The SS chains homodispersed into the hydrogel matrix without any phase separation. In comparison with volume phase transition temperature(VPTT) value of pure polyNIPAM hydrogel, the introduction of silk sericin molecular chains lead to an addition of temperature between 0.2 and 0.3℃. The maximum thermal decomposition temperature and DTG decomposition temperature increased gradually.