摘要： 采用 γ-氨丙基三乙氧基硅烷( KH550) 对高岭土进行表面改性，再将改性高岭土与异氰酸根封端的聚氨酯预聚体反应，制备含有无机粒子的高岭土改性水性聚氨酯乳液(WPU-K)。 采用傅里叶变换红外光谱(FT-IR)对改性高岭土进行表征;使用粒度仪测定了 WPU-K 乳液粒径;通过扫描电镜( SEM) 、透射电镜( TEM) 、拉力机和热重分析分别对胶膜的表面形貌、力学性能和热学性能进行了表征。 结果表明:随着改性高岭土质量分数的增加，乳液粒径变大、分布变宽，贮存稳定性下降，胶膜的热稳定性和硬度明显改善。 当改性高岭土质量分数为 8%时，与同组成聚氨酯相比，胶膜耐热性明显提高，拉伸强度增加 22.6%，邵 A 硬度由 53 增加至 82，吸水率减少 73.5%。

关键词: 改性高岭土, 接枝, 水性聚氨酯

Abstract: The kaolin was modified by KH550, and then a polyurethane emulsion(WPU- K) was synthesized by reaction of the modified kaolin with the isocyanate-terminated polyurethane prepolymer. The structure of the modified kaolin was characterized by Fourier transform infrared spectrometer(FT-IR). The particle size of WPU-K emulsion was determined by particle size analyzer. The morphology, mechanical properties and heat resistance of composite material(WPU-K) were observed via transmission electron microscopy(TEM), scanning electron microscope (SEM), tensile tests and thermogravimetry (TG). The results indicated that, with increasing the mass fraction of modified kaolin, the particle size of WPU-K emulsion was increased and the stability of emulsion was decreased, the hardness and the thermal stability of the films were improved obviously. When the mass fraction of modified kaolin was 8%, the cured film showed an improved thermal resistance as compared to pure polyurethane, furthermore, the tensile strength of the cured film was increased by 22. 6%, the Shore A hard- ness was increased from 53 to 82, and the water absorption was reduced by 73.5%.

Key words: modified kaolin, graft, waterborne polyurethane