聚丙烯酸镁/丙烯酸钠双交联水凝胶的制备及性能研究

Synthesis and characterization of poly(magnesium acrylate-sodium acrylate)hydrogels with dually cross-linked structure

以丙烯酸镁(MgA)和丙烯酸钠(SA)为单体、N,N'-亚甲基双丙烯酰胺(MBA)为共价交联剂,通过溶液聚合方法制备了系列聚丙烯酸镁/丙烯酸钠(PAMgA/x-PASA)双交联水凝胶,并测试分析了共聚水凝胶材料的结构、吸水特性和力学性能。结果表明,MBA作用下丙烯酸镁和丙烯酸钠形成了双交联结构的共聚水凝胶,显著提高了丙烯酸盐水凝胶的吸水溶胀比、保水性和重复吸水能力。当SA质量分数为20%时,水凝胶的吸水溶胀比达550%,较单一离子交联的聚丙烯酸镁提高近4倍;12 h干燥后的保水率约60%;而多次干燥-吸水溶胀以后,水凝胶的吸水溶胀比仍高达300%。此外,丙烯酸钠和MBA的加入对水凝胶的拉伸强度影响不大,但显著提高了材料的断裂伸长率,可从395%提高到690%。

A series of dually crosslinking hydrogels,PAMgA/x-PASA,are prepared via solution polymerization method with magnesium acrylate and sodium acrylate as monomers in the presence of N,N'-methylene bis-acrylamide(MBA),a covalent cross-linker.The structure characteristics,water absorption performance and mechanical property of PAMgA/x-PASA are determined and analyzed by means of Fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM)and universal testing machine.It is shown by the results that the copolymerized hydrogel with dually crosslinked structure is formed between magnesium acrylate and sodium acrylate under the action of MBA,which improves significantly the water absorption swelling ratio,water-retaining property and repeated water absorption capacity of acrylates hydrogel.The hydrogel can offer a 550%of water absorption swelling ratio as the mass ratio of sodium acrylate is 20%,which is 4 times that of single crosslinked polymagnesium acrylate.The hydrogel's water-retaining rate is around 60%after it has been dried for 12 h.After experiencing many times of drying-absorbing water to swell,the water absorption swelling ratio of the hydrogel remains as high as 300%.Furthermore,the addition of both sodium acrylate and MBA has a limited impact on the tensile strength of the hydrogel,while can help to enhance the elongation at break from 395%to 690%.