多环氧交联剂改性水性聚氨酯的性能

Properties of Aqueous Polyurethane Dispersion Modified by Multi-epoxy Crosslinkers

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醣分散体(PUD),同时也使PU膜具有高的亲水性。为提高PUD涂膜性能,分别采用间苯二甲胺四缩水甘油胺(GA-240)和山梨糖醇多缩水甘油醚(GE-60)对聚氨酯水分散体(PUD)进行交联改性,研究了交联剂对涂膜的耐水性、耐乙醇性、硬度、凝胶量和热稳定性的影响。傅立叶红外光谱(FTIR)显示PUD链上的羧基和胺基与GA-240和GE-60的环氧基发生了交联反应;涂膜性能测试表明:GA-240和GE-60均能提高PUD耐水性,耐乙醇性、抗寒裂性和耐沾污性。其中,GA-240还能将PUD的凝胶量提高至89.0%,硬度提高至0.83。最佳质量比分别为m(GA-240)∶m(PUD)=0.02,m(GE-60)∶m(PUD)=0.012。热失重分析(TGA)发现GA-240和GE-60均能提高胶膜的热稳定性。

The carboxyl groups of anionic aqueous polyurethane dispersions（PUD） serve as an internal emulsifier stabilizing PUD and cause the PUD film exhibit high hydrophilicity.In order to improve the performances of PUD film,PUD were crosslinked by sorbitol glycidyl ether（GE-60） and tetraglycidyl meta-xylene diamines（GA-240）,respectively.The effect of crosslinkers on the water-resistance,alcohol-resistance,hardness,and thermal stability of PUD films were studied.The FTIR spectrum showed that the carboxyl and amino groups of PUD react with epoxy groups of GA-240 and GE-60 during the drying process of PUD.The properties of PUD films indicated that the water solvent-resistance,flexibility and cold crack resistance of PUD films cured by GA-240 and GE-60 are improved impressively;GA-240 also increases the gel content and hardness of PUD films up by 89.0% and 0.83,respectively,and the optimal mass ratio of GA-240 and PUD（m（GA-240）∶m（PUD）） is 0.02,while the corresponding mass ratio of GE-60 and PUD（m（GE-60）∶m（PUD））is 0.012.The TGA curves determined that the thermal stability of PUD crosslinked by GA-240 and GE-60 is better than that of PUD.