吡嗪二羧酸-三聚氰胺双组分水凝胶的制备及性能

Preparation and Properties of the Two-component Hydrogels Based on Pyrazine Dicarboxylic Acid and Melamine

以3,6-二甲基-2,5-吡嗪二羧酸(P)和三聚氰胺(M)为组分,采用不同的摩尔比(1∶1,1∶2,1∶3)混合配制了3个样品PM11,PM12和PM13,并对其凝胶性能进行了测试.实验结果表明,PM能在水中及部分含水有机溶剂中形成稳定的凝胶,这些凝胶对酸碱具有良好的响应性能.采用扫描电子显微镜分析了3种水凝胶的微观形貌,均为纤维状的网络结构;红外光谱及紫外光谱测试结果表明氢键是形成凝胶的关键驱动力;XRD测试结果显示凝胶为层状结构.对PM12在不同pH值的水中的凝胶性能测试结果表明,在pH=3~11的范围内PM12均能形成凝胶.测试了PM12在混合溶剂中的凝胶性能,并将测试结果与混合溶剂的Hansen溶解度参数关联,以便用于分析溶剂与凝胶因子间的相互作用,所得结果亦表明氢键在凝胶形成的过程中起重要作用.

3,6-Dimethyl-pyrazine-2,5-dicarboxylic acid （P） and melamine （M） were mixed at different ratios to yield three mixtures, PMll, PM12 and PM13（numbers indicating respective molar ratios of components）. The gelation properties of the three PM samples were tested and all formed stable gels both in water and some aqueous organic solvents. The formed gels had good responding property to the stimuli of acid and base. SEM measurement was conducted to check the morphologies of hydrogels and the images presented fibrous networks. FFIR and UV-Vis spectra suggested that hydrogen bonding was the key driving force for the gel formation. The results of XRD indicated that the hydrogels were lamellar structure. The gelling behavior of PM12 in different water with various pH values were studied and the results showed that PM12 formed stable hydrogel in the pH range of 3--11. Furthermore, the gelation ability of PM12 in aqueous organic solvents were checked and the results were correlated with the Hansen solubility parameters of the mixed solvents in order to reveal the interactions between gelator and solvent. Expectedly, the gel formation. hydrogen bonding was found to play an important role in the gel formation.