聚脲基双壁微胶囊型自修复涂层及其拉伸力学特性研究

Study on Self-healing Coatings Based on Double-walled Polyurea Microcapsules and Its Tensile Properties

以己二胺为外芯、异佛尔酮二异氰酸酯(IPDI)预聚物为内芯,聚脲为内外囊壁,制备了聚脲基双壁微胶囊。应用光学显微镜(OM)和扫描电镜(SEM)测试分析了微胶囊的形成过程、表面形貌和粒径分布,利用红外光谱仪(FT-IR)与热重分析仪(TGA)对微胶囊的微观结构与热稳定性进行了表征。将微胶囊掺入环氧树脂中制备了自修复涂层,并借助力学试验机与数字散斑相关方法(DSCM)研究了涂层的抗拉性能及其断裂区域变形行为。结果表明:聚脲基微胶囊的双壁结构已形成,并将内外芯材成功包封,微胶囊呈球形分布,乳液和干燥状态下的平均粒径分别为3.8μm和0.7μm,且具有良好的热稳定性,其内外芯质量分数分别为7%和29%。含3%微胶囊的自修复涂层具有良好的自修复效果。

The double-walled polyurea microcapsules was synthesized,based on 1,6 hexanediamine as the outer core materials,isocyanate prepolymer as the inner core materials and polyurea as the of inner and outer wall material.The formation process,surface morphology and particle size distribution of the microcapsules were characterized by optical microscopy(OM)and scanning electron microscopy(SEM).The chemical structure and thermal stability were analyzed by Fourier transform infrared(FT-IR)and thermogravimetric analyzer(TGA).The self-healing coatings was prepared by incorporating the double-walled microcapsules into epoxy resin.The tensile properties and fracture regional deformation behavior of the coatings were investigated by mechanical test machine and Digital Speckle Correlation Method(DSCM).The results showed that a double-walled structure of the microcapsules was formed.The mean diameter of the microcapsules in the states of latex and powder,with good thermal stability,were respectively 3.8 μm and 0.8 μm,and their contents of inner and outer core were about 7% and 29%.The self-healing coatings with 3 wt% microcapsules provided a good selfhealing effect.