Synthesis and polymerization of a nonionic surfactant: Poly(ethylene oxide) macromonomer

Abstract

A polymerizable nonionic surfactant macromonomer, ω-methoxy poly(ethylene oxide)nundecyl-α-methacrylate (n = 40) has been synthesized from poly(ethylene glycol) methyl ether, 11-bromoundecanol, and methacryloyl chloride. The critical micelle concentration of the macromonomer is 6.6 × 10-5 mol/L at 25°C. The kinetics of its polymerization in aqueous medium follows conventional solution polymerization, i.e., first and half order with respect to the concentrations of the macromonomer and K2S2O8, respectively. The rate of its polymerization in water was extremely rapid (within 30 minutes) as compared to its solution polymerization in benzene (days). The activation energies for the macromonomer polymerization were 57 kJ/mol in water but 179 kJ/mol in benzene. The aqueous system produced polymers with a number-average degree of polymerization (DPn) ranging from about 130 to 160, but it was much lower (DPn = 7) for the benzene system. The possible micellar polymerization mechanism for the macromonomer is discussed.