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.