四甲基苯二甲基二异氰酸酯基水性聚氨酯的合成和性能

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10～30 nm，膜的分解温度达到275 ℃，24 h吸水率低于10%。

Synthesis and Properties of Waterborne Polyurethane Based Tetramethyl Xylene Diisocyanate

A series of waterborne 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.