水性聚氨酯/硅溶胶复合涂层的制备与性能

将水性聚氨酯乳液与硅溶胶共混,制备了水性聚氨酯/硅溶胶复合乳液。采用TEM、激光粒度分析仪、流变仪、ATR-FTIR、TG对复合乳液及其涂膜进行表征,探讨了硅溶胶用量对复合涂膜性能的影响。ATR-FTIR分析表明,聚氨酯分子和硅溶胶之间可以形成氢键,但不存在化学键结合;TEM、激光粒度分析测试表明,硅溶胶质量分数的增加,使复合乳液粒子粒径增大,粒度分布变宽,当硅溶胶质量分数20%后,乳胶粒子间易发生团聚;流变分析发现,加入硅溶胶后,乳液的表观黏度(ηa)增大,假塑性增强。性能测试结果表明,硅溶胶质量分数20%时,复合乳液具有好的储存稳定性,复合涂膜表现出很好的热稳定性,48 h吸水率仅为18.94%,同时表现出很好的耐溶剂性能,拉伸强度达到28.98 MPa,铅笔硬度达2H,附着力0级。

The Preparation and Characterization of Waterborne Polyurethane/Colloidal Silica Hybrid coatings

Hybrid emulsions containing inorganic nano particles were prepared by blending waterborne polyurethane (WPU) emulsions with colloidal silica. The hybrid emulsion and its film were characterized by TEM, laser particle analyzer, rheometer, ATR-FTIR, and TG respectively. The effects of silica content on the properties of the film were studied. The ATR-FTIR test results confirm that there is no chemical bond formation between silica particle and urethane polymer chains but hydrogen bonding. TEM and laser particle analyzer examinations showed that the average particle size of the hybrid emulsions increases and particle size distribution become wider with the increasing content of colloidal silica, the aggregation of silica particle in the hybrid emulsion would happen in the case of SiO2wt%>20%. The rheological analysis reveals that the apparent viscosity ( ) and pseudoplasticity of the hybrids are increased with increasing silica content. The property tests indicated that at about 20% silica content, the stability of the hybrid emulsion is good, its films show much better thermal stability, its water absorption was only 18. 94%(after 48h) also with higher performance in solvent resistance, tensile strength increases to 28.98MPa, pencil hardness is 2H,adhesion is 0 grade.