疏水缔合聚丙烯酰胺水凝胶的研制及自愈机理

Developing of Hydrophobically Associated Polyacrylamide Hydrogels and Its Self-Healing Mechanism

采用疏水缔合的物理交联方式,将十二烷基硫酸钠(SDS)、氯化钠(NaCl)、甲基丙烯酸十八烷酯(SMA)反应所得的可聚合胶束与丙烯酰胺(AM)共聚缩合,制备出具有自愈合特性的聚丙烯酰胺(PAM)水凝胶,采用动态光散射测试、扫描电镜、红外光谱、热分析等表征手段对其理化性能进行了研究,并对其自愈合机理进行分析探讨。结果表明,制备所得PAM水凝胶含水率可达95%左右;SMA含量对PAM水凝胶含水率影响不明显,但SMA含量越高,所得水凝胶网络结构越紧密,孔隙尺寸越小,抗压强度、韧性和自愈率越高,但拉伸强度却随之下降。优选出的最佳工艺参数为:7%g/mL SDS溶液加入0.9 mol/L NaCl溶液中所得胶束尺寸最大,且疏水单体SMA的摩尔分数为AM单体的2%时,所得PAM水凝胶的抗拉强度和自愈率均最佳。

Polyacrylamide(PAM)hydrogels with self-healing properties were prepared by copolymerization and condensation of acrylamide(AM)with the polymerizable micelles obtained from the reaction of sodium dodecyl sulfate(SDS),sodium chloride(NaCl)and octadecyl methacrylate(SMA)by hydrophobically associating physical crosslinking method.The dynamic light scattering,scanning electron microscopy,infrared spectroscopy and other characterization methods were used to study its properties and the self-healing mechanism.The results show that the water contents of PAM hydrogels can reach about 95%;the contents of SMA have no obvious effect on the water contents of PAM hydrogels,but have a significant effect on its network structure.The higher the content of SMA,the tighter the network structure,the smaller the pore size,the higher the compressive strength,toughness and self-healing rate,but the lower the tensile strength.The optimum technological parameters are as follows:when 0.07 g/mL SDS solution is added to 0.9 mol/L NaCl solution,the micelle size is the largest,and the content of hydrophobic monomer SMA is 2%of AM monomer,the tensile strength and self-healing rate of PAM hydrogels are the optimal.