环氧树脂用量对水性聚氨酯胶膜结晶性能的影响

以异佛尔酮二异氰酸酯、六亚甲基二异氰酸酯、聚己二酸1,4-丁二醇酯为主要原料,1,4-丁二醇为小分子扩链剂,乙二胺基乙磺酸钠为亲水性扩链剂,环氧树脂E-51为改性剂,合成了固含量为50%的环氧树脂改性磺酸盐型水性聚氨酯乳液,并采用FT-IR、XRD、SEM、AFM、DSC和DMA方法考察环氧树脂用量对乳胶膜结晶性能的影响.结果表明:随着环氧树脂用量的增多,XRD谱图中21.2°和24.3°处的两个尖锐的谱峰高度明显变小,SEM和AFM图中乳胶膜硬段和软段的相分离程度显著减弱,DSC曲线上可以观察到清晰的胶膜熔融峰和结晶峰,胶膜的结晶度减小,DMA曲线上改性树脂软段的玻璃化温度有朝低温方向移动的趋势,说明环氧树脂的加入降低了聚氨酯胶膜的结晶性能.

Effects of Epoxy Resin Content on Crystallization Property of Cast Films of Waterborne Polyurethane

In this paper,epoxy resin-modified sulphonated waterborne polyurethane emulsions with a solid content of 50% were synthesized,with isophorone diisocyanate,hexamethylene diisocyanate and polyethylene glycol adipate diol as the main raw materials,and with 1,4-butanediol,N-(2-aminoethyl)-amino ethane sulphonated sodium and epoxy resin E-51 respectively as the small-molecular chain extender,the hydrophilic chain extender and the modifier.Then,the influences of epoxy resin content on the crystallization property of the cast films were investigated by means of FT-IR,XRD,SEM,AFM,DSC and DMA.The results show that,with the increase of epoxy resin content,the two sharp diffraction peaks at 21.2° and 24.3° in XRD spectra are disrupted,the phase separation of the hard segment from the soft one of the cast films shown in SEM and AFM images is inhibited,distinct exothermic and endothermic peaks in DSC curve can be easily found,the relative crystallinity of the cast films decreases,and the glass transition temperature of the soft segment shown in DMA curves shifts to a lower value.All these above-mentioned statements indicate that the addition of epoxy resin weakens the crystallization of the cast films.