封端型环氧树脂改性聚氨酯乳液的制备与膜性能研究

Preparation and Property Study of Terminated Waterborne Polyurethane Emulsion by Epoxy Resin

以环氧树脂E20作为大分子多元醇,甲苯二异氰酸酯(TDI)、聚酯多元醇1000(EG/BG/AA)、二羟甲基丙酸(DMPA)为主要原料,合成了环氧树脂改性聚氨酯预聚体,再以甲醇进行封端后乳化,得到封端型环氧树脂改性聚氨酯乳液。采用傅立叶红外光谱(FT-IR)对不同反应阶段的聚合物结构进行表征,结果表明,异氰酸酯基团(—NCO)和环氧树脂E20分子上的仲羟基发生了反应。研究了DMPA用量和E20添加量对乳液贮存稳定性、粒径以及浇铸膜性能的影响;并通过热重分析仪(TG)和扫描电镜(SEM)对浇铸膜的热性能和断面形貌进行表征。结果表明,随着E20添加量的增多,浇铸膜的耐水性、力学性能和热稳定性均得到提升。当E20添加量超过20%时,改性后的浇铸膜断面呈现脆性断裂。

The epoxy-polyurethane resin emulsion was prepared with toluene diisocyanate （TDI）, polyester polyols 1000 （ EG/BG/AA）, epoxy resin （E20） and dimethyopropionic acid （DMPA） as main raw materials. The polymer of different reaction phase was characterized by Fourier transform infrared spectroscopy （FTIR）, and the results show that the secondary hydroxyl on epoxy reacted with the isocyanates groups （-NCO）. The influence of the amount of DMPA and epoxy resin on the storage stability, particle size of the emulsion and the cast film＇s properties were studied. The results show that the water resistance and mechanical property of the film can be enhanced by increasing the content of epoxy resin. The results of thermogravimetric analysis show that the thermal stability of the modified polyurethane is improved. The fracture surface of the modified system displays brittle fracture feature.