四甲基苯二甲基二异氰酸酯基水性聚氨酯的合成和性能

摘要

采用四甲基苯二甲基二异氰酸酯、聚酯二元醇和二羟甲基丙酸为原料,合成了一系列具有不同异氰酸根与羟基摩尔比(n(-NCO)/n(-OH))的聚氨酯乳液.研究了n(-NCO)/n(-OH)对水性聚氨酯性能的影响.结果表明,当该比值增加时,乳液的粒径增大,分布变宽,结晶性降低,耐热性下降,耐水性能呈现降低的趋势.当异氰酸根与羟基摩尔比为3时,四甲基苯二甲基二异氰酸酯基水性聚氨酯的乳液粒径为10～30nm,膜的分解温度达到275℃,24h吸水率低于10％.%A series of waterbome polyurethane ( WPU) dispersions with different molar ratio of -NCO to -OH(n(-NCO)/n(-OH)) were synthesized using tetramethyl xylene diisocyanate(TMXDI), polyester diol and dimethylolpropionic acid as raw materials. The effect of n(-NCO)/n(-OH) on the properties of WPU was investigated. The experiment results showed that with the increase of n(-NCO)/n(-OH), the particle size increased while the particle size distribution became wider; the crystallinity, thermostability and the water resistance tend to decrease as well. When n(-NCO)/n{-OH) was 3. 0, the particle size of WPU based TXMDI was fallen in the range of 10 to 30 nm, the decomposition temperature and 24 h water absorption of WPU film were 275 ℃ and below 10% , respectively.