Synthesis of poly(ethylene glycol)-modified urethane acrylates and their soap-free emulsification

In order to prepare the soap-free emulsion of urethane acrylates, poly(ethylene glycol)-modified urethane acrylates (PMUA), containing poly(oxyethylene) chains as terminal groups, were synthesized by reaction of poly(ethylene glycol) (PEG) with residual isocyanate groups. The size of the droplets of PMUA emulsions decreases as the molar ratio of PEG to 2-hydroxyethyl methacrylate (2-HEMA) increases. The interfacial activity of PMUA was confirmed by the measurement of the adsorption isotherm at the water/benzene interface. The chain length of poly(oxyethylene) and the type of polyol (PTMG, PPG) affects significantly the size of the droplets and the stability of the PMUA emulsions.