Abstract: A series of cationic waterborne polyurethanes (CWPU) with different degree of crosslinking density using triisopropanolamine( TIFA) as crosslin king agent. The attenuated total reflection (ATR )was used to characterize the structure of the CWPU. The particle size distribution of CWPU emulsions and the mechanical, thermal, and water resistant properties of the cured film were measured. When the content of TIFA increased, the average particle size of CWPU emulsion decreased first and then increased, in addition, the hardness and tensile strength of the cured film increased, the glass transition temperature of soft segment increased, the water resistance and heat resistance performance were also improved. When addition amount of TIPA was 1. 80%, the mechanical performance of the cured film was optimal, the tensile strength was 17. 5 MPa, the Shore hardness was D65, and the heat resistance was also optimized; When addition amount of TIPA was 1. 35%, the film water absorption was 4. 2% indicating the optimal water resistance, and the emulsion particle size was smaller, which enabled the CWPU to be suitable for wood sealing coat.

Key words: cationic waterborne polyurethane, Crosslink, triisopropanolamine, sealing coat

摘要： 以三异丙醇胺（TIPA）为交联剂制备了不同交联度的阳离子型水性聚氨酯（CWPU）。 用红外表征其结构，并分别对 CWPU 乳液的粒径分布和胶膜的机械性能、热学性能以及耐水性进行了测试。 结果表明：随着 TIPA 含量的增加，CWPU 乳液的平均粒径先减小后增大，胶膜硬度增加，拉伸强度增大，软段玻璃化转变温度提高，耐水性和耐热性提升。 当 TIPA 加入量为 1.80%时，胶膜机械性能最优，拉伸强度达 17.5MPa，硬度达邵 D65，耐热性也最好；当 TIPA 加入含量为 1.35%时，胶膜耐水性最好，96 h 吸水率为4.2%，并且乳液粒径较小，较适合作木器封底漆。

关键词: 阳离子水性聚氨酯, 交联改性, 三异丙醇胺, 封底漆