原位纳米SiO2改性阳离子水性聚氨酯乳液的合成及其性能研究

采用聚丙二醇、1,4-丁二醇、阳离子扩链剂N-甲基二乙醇胺等原料，合成聚氨酯预聚物，在预聚物中加入正硅酸乙酯，通过正硅酸乙酯水解将SiO₂粒子引入，合成不同含量（正硅酸乙酯与预聚物质量比）的5种自乳化阳离子水性聚氨酯乳液。通过对乳液官能团结构进行表征、乳液粒径尺寸分析、耐热稳定性能分析。在红外表征中Si-O键的出现，可以表明乳液中成功引入SiO₂粒子。通过粒径分析仪和热重分析仪可以得出结论：随着SiO₂含量的增加，粒径反而减小，耐热性能却有所提高，表面张力也存在增大的趋势。原位合成聚氨酯乳液具有分散性好、储存稳定、热稳定性高等优点。

Synthesis and Study of in Situ Nano-SiO_2 Cationic Waterborne Polyurethane Emulsion

The polyurethane prepolymer was synthesized by using raw materials, including polypropylene glycol, 1,4-butanediol and cationic chain extender Nmethyldiethanolamine. Then, orthosilicate was added to the prepolymer and SiO₂ particles were prepared successfully by hydrolysis of ethyl orthosilicate. Five kinds of cationic aqueous polyurethane emulsions with different contents (mass ratio of orthosilicate/prepolymer) were obtained. The characterizations of emulsion functional group structure, emulsion particle size analysis and heat stability analysis were carried out. The appearance of Si-O bonds in infrared characterization can indicate the successful introduction of SiO₂ particles in the emulsion. Through the particle size analyzer and thermogravimetric analyzer, it can be concluded that with the increase of SiO₂ content, the particle size decreases, the heat resistance is improved, and the surface tension also increases. The preparation of nano-SiO₂ cationic waterborne polyurethane emulsionthe possess good dispersion, stable storage and high thermal stability.