Chen Junhua, Zeng Zhihao, Liu Can, Wang Xuan, Li Shiting, Ye Feihua, Li Chunsheng, Guan Xiaoxiao
School of Environmental and Chemical Engineering, Zhaoqing University, Zhaoqing 526061, China.
Guangdong Provincial Key Laboratory of Environmental Health and Land Resource, College of Environmental and Chemical Engineering, Zhaoqing University, Zhaoqing 526061, China.
Polymers (Basel). 2023 Sep 11;15(18):3725. doi: 10.3390/polym15183725.
Aqueous polyurethane is an environmentally friendly, low-cost, high-performance resin with good abrasion resistance and strong adhesion. Cationic aqueous polyurethane is limited in cathodic electrophoretic coatings due to its complicated preparation process and its poor stability and single performance after emulsification and dispersion. The introduction of perfluoropolyether alcohol (PFPE-OH) and light curing technology can effectively improve the stability of aqueous polyurethane emulsions, and thus enhance the functionality of coating films. In this paper, a new UV-curable fluorinated polyurethane-based cathodic electrophoretic coating was prepared using cationic polyurethane as a precursor, introducing PFPE-OH capping, and grafting hydroxyethyl methacrylate (HEMA). The results showed that the presence of perfluoropolyether alcohol in the structure affected the variation of the moisture content of the paint film after flash evaporation. Based on the emulsion particle size and morphology tests, it can be assumed that the fluorinated cationic polyurethane emulsion is a core-shell structure with hydrophobic ends encapsulated in the polymer and hydrophilic ends on the outer surface. After abrasion testing and baking, the fluorine atoms of the coating were found to increase from 8.89% to 27.34%. The static contact angle of the coating to water was 104.6 ± 3°, and the water droplets rolled off without traces, indicating that the coating is hydrophobic. The coating has excellent thermal stability and tensile properties. The coating also passed the tests of impact resistance, flexibility, adhesion, and resistance to chemical corrosion in extreme environments. This study provides a new idea for the construction of a new and efficient cathodic electrophoretic coating system, and also provides more areas for the promotion of cationic polyurethane to practical applications.
水性聚氨酯是一种环保、低成本、高性能的树脂，具有良好的耐磨性和较强的附着力。阳离子水性聚氨酯由于其制备工艺复杂，乳化分散后稳定性差且性能单一，在阴极电泳涂料中受到限制。引入全氟聚醚醇（PFPE-OH）和光固化技术可以有效提高水性聚氨酯乳液的稳定性，从而增强涂膜的功能性。本文以阳离子聚氨酯为前驱体，引入PFPE-OH封端，并接枝甲基丙烯酸羟乙酯（HEMA），制备了一种新型的紫外光固化氟化聚氨酯基阴极电泳涂料。结果表明，结构中全氟聚醚醇的存在影响了闪蒸后涂膜含水量的变化。基于乳液粒径和形貌测试，可以推测氟化阳离子聚氨酯乳液是一种核壳结构，疏水端包裹在聚合物内部，亲水端位于外表面。经过磨损测试和烘烤后，发现涂层中的氟原子从8.89%增加到27.34%。涂层对水的静态接触角为104.6±3°，水滴滚落无痕，表明涂层具有疏水性。该涂层具有优异的热稳定性和拉伸性能。该涂层还通过了耐冲击性、柔韧性、附着力以及在极端环境下的耐化学腐蚀性测试。本研究为构建新型高效的阴极电泳涂料体系提供了新思路，也为阳离子聚氨酯推广至实际应用提供了更多领域。
