Abstract:

The polyaddition of isophorone diisocyanate (IPDI) with hydrophobic diol was performed in miniemulsion to obtain water-borne polyurethane.The polymer structure was characterized with FTIR to determine the concentration ratio of urethane to urea group.The effects of hydrophobic diol, vinyl monomers, and such experiment parameters, as temperature, catalyst and surfactant on the competition of the main reaction (polyaddition of isocyanate- hydroxyl) with the side reaction (hydrolysis of isocyanate) were studied.Based on the experimental results, the physical model of the competition was established.It was found that the high reactivity of diol and the high hydrophilicity of vinyl monomer could favor the polyaddition.It was also shown that the hydrolysis could be restrained by decreasing surfactant concentration and decreasing temperature and the amount of catalyst.However, the hydrolysis could be restrained by increasing the surfactant concentration when polydimethyl siloxane (PDMS) took part in polymerization.

Key words:

聚氨酯, 细乳液, 异佛尔酮二异氰酸酯, 水解反应

摘要：

采用异佛尔酮二异氰酸酯(IPDI)与憎水性二醇进行原位细乳液聚合制备水性聚氨酯，根据已建立的FTIR定量分析方法来表征聚合产物结构，通过产物中氨酯键/脲键的浓度比来研究主反应（加聚）与副反应（水解）的竞争。考察了憎水性二醇、乙烯基单体、反应温度、催化剂和乳化剂等因素对主副反应竞争情况的影响，并建立细乳液中加聚与水解反应竞争的物理模型。研究发现，二醇的反应活性越高越有利于加聚反应;乙烯基单体的引入能够抑制水解反应，促进加聚反应，而且其水溶性越小，加聚反应更容易在竞争中占优势;降低反应温度和增加催化剂浓度可促进加聚反应，抑制水解反应。

关键词:

聚氨酯, 细乳液, 异佛尔酮二异氰酸酯, 水解反应