高性能自修复微胶囊预聚物组成的研究

Study on the Prepolymer Components of High-Performance Self-Healing Microcapsules

为了指导高性能自修复微胶囊的制备研究,利用偏光显微熔点仪、红外光谱和核磁共振氢谱定量研究了微胶囊预聚物组成随反应条件如反应温度、pH值和甲醛-尿素物质的量比的变化.研究结果表明,升高体系温度和pH值都会显著促进副反应的发生从而降低产物中二羟甲基脲的产率;而提高甲醛-尿素的物质的量比,二羟甲基脲的产率增加,同时三羟甲基脲的产率降低.此外,还研究了升温过程中反应体系的温度变化情况.研究发现:升温速率一定时,反应体系的温度变化均匀,没有温度骤变阶段.

Abstract It is well known that the components of microcapsule prepolymers have great influence on the structures and morphologies of the resultant selfhealing microcapsules. The synthesis of highperformance selfhealing microcapsules is benefited to the presence of highcontent multimethylol urea in the reaction system. In this contribution, the components of microcapsule prepolymers prepared under different reaction conditions, including temperatures, pH values and mole ratio of formaldehyde to urea, were studied and quantiflcationally analyzed using polarized microscopic melting point meter, infrared spectroscopy and 1H NMR spectroscopy. It was found that increasing the temperature and pH value in the reaction system could significantly promote the secondary reaction respectively, resulting in the decreased yield of dimethylol urea in the reaction system. When increasing the mole ratio of formaldehyde to urea, the yield of dimethylol urea in the reaction system increased, and the yield of trimethylol urea decreased simultaneously. Furthermore, the temperature of the reaction system during the heating process was monitored, and it indicated that the temoerature changed at a constant oath when a fixed heating rate was oerformed.