高强度疏水缔合水凝胶的重塑性能机理

将丙烯酰胺和少量的疏水单体辛基酚聚氧乙烯(4)醚丙烯酸酯溶解于十二烷基硫酸钠水溶液中,采用胶束共聚的方法成功制备了疏水缔合水凝胶(HA-gels)。HA-gels除具有良好的力学性能以外,还具有重塑性能。为了研究HA-gels的重塑性能,对其应力松弛行为进行了表征。研究结果表明,HA-gels应力松弛过程可以分为四个阶段:第一阶段是交联点间亲水长链的应力松弛过程;第二阶段是交联点间亲水长链已经高度取向;第三阶段是交联网络的结构重排过程;第四阶段是HA-gels的应力完全消除。因此,HA-gels内的交联点在外力的作用下可以解缔合和重新缔合来实现交联网络的结构重组,从而赋予了HA-gels的重塑性能。

Remolding Mechanism of Hydrophobic Association Hydrogels with High Mechanical Strength

Hydrophobic association hydrogels(HA-gels) were successfully prepared through micellar copolymerization of acrylamide and a small amount of octylphenol polyoxyethylene acrylate in an aqueous solution containing sodium dodecyl sulfate.HAgels exhibited excellent mechanical properties and remolding property.In order to study the remolding property,the stress-relaxation behavior of HA-gels was characterized.The result shows that the stress-relaxation behavior of HA-gels can be divided into four stages: stress relaxation of hydrophilic polymer chains between cross-linked points(Ⅰ);hydrophilic polymer chains between crosslinked points have a high level of orientation(Ⅱ);structural reorganization of the cross-linked network(Ⅲ);stress of HA-gels is gone entirely(Ⅳ).Therefore,for HA-gels,the capability of remolding results mainly from their unique network.Due to the network of HA-gels is a reversible three-dimensional physical cross-linked network,the structure rearrangement of cross-linked network can be achieved through dissociation and reassociation of cross-linking points under the condition of external forces.Therefore,this unique network endows remolding property of HA-gels.