NCO/OH摩尔比对水性聚氨酯性能的影响

Effects of the Ratio of NCO/OH on Properties of Waterborne Polyurethane

采用预聚体法,以聚酯多元醇、甲苯二异氰酸酯、二羟甲基丙酸(DMPA)制备了聚酯型水性聚氨酯乳液,考察了异氰酸酯基(—NCO)与羟基(—OH)摩尔比对乳液的粒径、运动黏度、胶膜吸水性及力学性能的影响,结果表明,随着NCO/OH的增加,聚氨酯乳液的粒径增大,运动黏度及其胶膜的吸水性先增大后减小,胶膜的拉伸强度提高,但其断裂伸长率有所降低。最佳的NCO/OH为3.0。

Polyester waterborne polyurethane emulsions were prepared with polyester polyol, toluene -2,4 - dissocyanate （TDI） and 2,2 - dimethylolpropionic acid （DMPA） by the method of prepolymerization. The effects of molar ratio of NCO/OH on particle size, kinetic viscosity, the water absorption and mechanical properties of membranes from emulsions were sions and the water absorption decreased particle size of emulsions and the tensile Suitable molar ratio of NCO/OH is 3.0. investigated. The results showed that the kinetic viscosity of emulfirst then increased with the increase of molar ratio of NCO/OH, the strength of membranes improved, but elongation at break decreased.