摘要
阴离子水性聚氨酯(PU)含有羧基起内乳化剂作用稳定水性聚氨酯分散体(PUD),同时也使PU膜具有高的亲水性。为提高PUD涂膜性能,采用氮丙啶和聚碳化二亚胺对其进行交联改性。利用红外光谱和热重分析表征了PUD固化涂膜,结果表明:在室温下氮丙啶和聚碳化二亚胺可与PUD链上的羧基反应,PUD涂膜性能的提高取决于固化剂种类:如氮丙啶能显著改善涂膜耐水性、耐溶剂性及耐污染性,因其能提高涂膜的凝胶含量至92.63%,涂膜硬度至0.72,其最佳的氮丙啶与羧基的质量比为5.84;另一方面,聚碳化二亚胺能改善涂膜的附着力、柔韧性及抗冷脆性,最佳的聚碳化二亚胺与羧基的质量比为10.37。TGA曲线表明聚碳化二亚胺能提高PUD涂膜的热稳定性,而氮丙啶则降低涂膜的热稳定性。
Anionic aqueous polyurethane （PU） contains the carboxyl groups which serve as internal emulsifier stabilizing aqueous PU dispersions （PUD）; at the same time, it causes the PUD film to exhibit a high hydrophilicity. In order to improve the performances of PUD film, the PUDs were crosslinked by aziridine derivatives and polycarbodiimide, respectively. The crosslinked PUD films were characterized by FT-IR spectrum and thermogravimetric analysis （TGA）; the results indicate that the aziridine derivatives and polycarbodiimide react with the carboxyl groups of PUD at room temperature. The properties of the cured PUD film were improved according as the curing agent＇s category used. For example, the aziridine derivatives can improve the water-, solvent- and pollution-resistance properties of the cured films greatly; it may be attributed to the increase of their gel content and hardness, which can be increased up to 92.63% and 0.72, respectively, and it was found that the optimal mass ratio of aziridine derivatives to carboxyl groups is 5.84. On the other hand, polycarbodiimide can improve the adhesion, flexibility and cold crack-resistance of the cured films, and the optimal mass ratio of polycarbodiimide to carboxyl groups is 10.37. The TGA curves of cured films show that their thermal stabilities are increased by polycarbodiimide and decreased by aziridine derivatives.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2009年第4期650-654,共5页
Journal of Chemical Engineering of Chinese Universities
基金
粤港关键领域重点突破项目(20040204)
关键词
水性聚氨酯
交联改性
氮丙啶
聚碳化二亚胺
aqueous polyurethane dispersion
crosslinked
aziridine derivatives
polycarbodiimide
