溶剂蒸发相分离法制备微胶囊及其性能研究

Preparation and Performance Investigation of Microcapsules Synthesized by Solvent Evporation and Internal Phase Separation Technic

以聚甲基丙烯酸甲酯(PMMA)为囊壁,以环氧单体2020A为囊芯,采用溶剂蒸发相分离法制备出具有自修复性能的微胶囊,并将微胶囊复合到水性环氧涂层中,制备出自修复涂层,并对微胶囊和涂层的性质做了进一步研究。用扫描电镜(SEM)和红外光谱(FT-IR)表征了微胶囊的形貌结构和化学组成,用热重分析法(TGA)研究了微胶囊的热稳定性和囊芯装载率,用SEM表征了涂层的划痕修复48 h后形貌,并用Tafel电化学测试表征修复涂层的极化曲线,拟合出相应的腐蚀电流密度(I_(corr))和腐蚀电压(E_(corr)),来观察涂层的修复能力。结果表明:采用溶剂蒸发相分离方法,PMMA能够对2020A进行包裹形成微胶囊,且微胶囊有着圆整的球形形貌,平均直径为1.45μm。添加微胶囊的环氧复合涂层有着很好的自修复性能,与纯环氧涂层相比,添加15%(wt)微胶囊的涂层,I_(corr)下降三个数量级,修复效率(HE)达到99.61%。

Epoxy monomer 2020A was encapsulated with polymethyl methacrylate(PMMA)by solvent evaporation and phase separation technic to prepare self-healing microcapsules.The microcapsules were added into the water-borne epoxy coating to endow the coating with self-healing function.The morphology,structure and properties of the microcapsules and the coatings were systematically studied.Scanning electron microscopy(SEM)and infrared spectroscopy(FT-IR)were used to characterize the morphology and chemical composition of the microcapsules.Thermogravimetric analysis(TGA)was used to study the thermal stability and core material loading ability of the microcapsules.SEM and corrosion current density(I_(corr))and corrosion potential(E_(corr))fitted from Tafel polarization curves were used to study the morphology and self-healing property of the coatings after a 48 hours healing process.The results demonstrated that PMMA can encapsulated 2020A by the solvent evaporation phase separation technic to form microcapsules,which had a round spherical morphology with an average diameter of 1.45μm.The epoxy composite coating with microcapsules owned significant self-healing performance.Compared with the pure epoxy coating,the I_(corr) of the coating with 15%(wt)microcapsules decreased by three orders of magnitude,and the healing efficiency(HE)reached to 99.61%.