季铵化壳聚糖/聚苯乙烯半互穿水凝胶的制备及溶胀动力学

Preparation and Swelling Dynamics of Quaternized Chitosan/Polystyrene Hydrogel Based Semi Interpenetrating Networks

利用高季铵化取代度的季铵化壳聚糖(QCS)和苯乙烯单体为原料,借助原位乳液聚合、交联的手段制备具有半互穿网络结构的高分子凝胶。该凝胶具有较高的力学强度和较快的溶胀速度,溶胀过程满足Schott’s二级溶胀动力学方程。随凝胶中聚苯乙烯(PS)含量增加,凝胶的拉伸强度增强,断裂伸长率降低,热稳定性增强,含水量下降,吸水溶胀速度加快。当PS质量分数为21%时,干凝胶的拉伸强度为20 MPa,吸水溶胀过程在3 min内达到平衡。扫描电镜结果表明,凝胶结构中没有明显的相分离现象。同时,热稳定性测定结果表明,该凝胶具有良好的热稳定性能,最低分解温度高于150℃。

A high strength hydrogel with an interpenetrating network （IPN） structure from quaternized chitosan （QCS） with the high degree of quaternization and polystyrene （PS） was designed. The results show that chemical crosslinking, physical entanglement and PS precipitates are the dominant parameters for the improvement of mechanical properties. The chitosan structure transfers from crystal phase to amorphous one due to the introduction of quaternary ammonium groups, therefore the hydrophilic is enhanced. With increasing the PS content in the hydrogel, the tensile strength of hydrogel is reinforced, the elongation at break is decreased, thermal stability is enhanced, the water content is decreased, and the swelling rate is speed up. The tensile strength rises up to 20 MPa for the dry hydrogel with the mass fraction of PS 21%. At this time, the swelling equilibrium can be reached within 3 min. SEM characteristic results reveal that PS precipitates scatter in the QCS matrix homogeneously which disperses the applied stress and improves the hydrogel toughness. And TGA results show that the hydrogel has a good thermal property, and the lowest temperature of decomposition is more than 150 ℃.