Chen Junhua, Peng Kaimei, Tu Weiping
School of Chemistry and Chemical Engineering, South China University of Technology Guangzhou 510640 China
School of Environmental and Chemical Engineering, Zhaoqing University Zhaoqing 526061 China.
RSC Adv. 2019 Apr 9;9(20):11013-11025. doi: 10.1039/c9ra01500k.
Two modified types of hyperbranched polymer were successfully prepared using hyperbranched polyether (HBPE) as a matrix, -5-norbornene--2,3-dicarboxylic anhydride (CDA) or -phthalic anhydride (PA) as a modifier and by grafting an NCO-terminated compound (IPDI-HEA). The modified hyperbranched polymers were incorporated into a typical water-soluble polyacrylate (WPA) as crosslinkers to develop high-performance waterborne UV-curable coatings electrophoretic deposition (EPD). Although the particle size of the electrophoretic dispersion increased from 43.8 nm to 164 nm, no microphase separation occurred, and the smooth SEM images of the coatings confirmed their uniformity. The rate of photopolymerization ( ) and percentage conversion of the double bonds increased with increasing active unsaturated double bond content, and were partially affected by steric effects. Thermal gravity analysis and tensile tests indicated that the UV-curable EPD coating films exhibited better thermal stability due to their hyperbranched structure, soft and hard segment content and crosslinking density. The coated tin plate could resist chemical corrosion after immersion in NaCl solution. The coatings demonstrated strong adhesion to extremely bent tin plates and outstanding tolerance to knife-scratches and impact. This is a promising method for the design of desirable coatings in the EPD industry.
以超支化聚醚（HBPE）为基体，-5-降冰片烯-2,3-二羧酸酐（CDA）或邻苯二甲酸酐（PA）为改性剂，通过接枝异氰酸酯封端化合物（IPDI-HEA），成功制备了两种改性超支化聚合物。将改性超支化聚合物作为交联剂引入典型的水溶性聚丙烯酸酯（WPA）中，以开发用于电泳沉积（EPD）的高性能水性紫外光固化涂料。尽管电泳分散体的粒径从43.8 nm增加到164 nm，但未发生微相分离，涂层的光滑扫描电子显微镜图像证实了其均匀性。光聚合速率（）和双键转化率随活性不饱和双键含量的增加而提高，并部分受空间位阻效应影响。热重分析和拉伸试验表明，紫外光固化EPD涂膜由于其超支化结构、软硬段含量和交联密度而表现出更好的热稳定性。涂覆的马口铁在浸入NaCl溶液后能抵抗化学腐蚀。该涂层对极度弯曲的马口铁表现出很强的附着力，对刀划痕和冲击具有出色的耐受性。这是一种在EPD行业设计理想涂层的有前景的方法。
