非冻结水对微球复合水凝胶机械性能的影响

本文旨在用DSC的方法研究水凝胶结合水的能力与韧性的关系。 分别以甲基丙烯酸丁酯(BMA)或甲基丙烯酸六氟丁酯(HFBMA)和烯丙基胺为单体,制备了2种核壳纳米微球(BMA微球和HFBMA微球)。 再以其作为大分子引发剂和交联剂,制备了微球交联复合水凝胶(BMA-H凝胶和HFBMA-H凝胶)。 通过差示扫描量热仪(DSC)、傅里叶变换红外光谱仪(FTIR)和透射电子显微镜(TEM)等技术手段研究凝胶的结构和性能。 结果表明,HFBMA-H凝胶具有更好的机械性能,其拉伸强度和断裂伸长率分别可达280 kPa和3960%,远高于BMA-H凝胶(101 kPa,2700%)。 通过对2种复合凝胶体系内不同状态的水进行分析,发现HFBMA-H凝胶的非冻结水的质量分数明显高于BMA-H凝胶,这种非冻结水的增塑作用对于凝胶机械强度的提升具有重要影响。

Effect of Non-freezing Water on the Mechanical Properties of Microspherical Composite Hydrogels

The aim of this paper is to study the relationship between the ability to combine water and the toughness of hydrogel by means of differential scanning calorimetry(DSC). N-butyl methacrylate(BMA) or 2,2,3,4,4,4-hexafluorobutyl methacrylate(HFBMA) and allylamine were chosen as monomers to synthesize core-shell nanospheres(named BMA nanosphere or HFBMA nanosphere). Then, the two nanospheres were used as macromolecular initiators and crosslinking agents to prepare nanospherical composite hydrogels(named BMA-H hydrogel or HFBMA-H hydrogel). DSC, Fourier transform infrared spectrometer(FTIR) and transmission electron microscopy(TEM) were used to characterize the structures and properties of hydrogels. The results of mechanical performance analysis indicate that the HFBMA-H hydrogel has better mechanical properties and its tensile strength and fracture elongation are up to 280 kPa and 3960%, respectively, which are much higher than those of BMA-H hydrogel(101 kPa, 2700%). DSC was used to investigate the state and proportion of water in composite hydrogels with different kinds of nanospheres. The results show that the non-freezing water content of HFBMA-H hydrogel is far higher than that of BMA-H hydrogel under the same water content, and the plasticizing effect of non-freezing water has an important effect on the mechanical strength of the hydrogel.