Synthesis and Characterization of Copolymers of Methyl Methacrylate and 2-Ethoxyethyl Methacrylate

The free-radical initiated copolymerizations of methyl methacrylate (MMA) with 2-ethoxyethyl methacrylate (2-EOEMA) were carried out using 2,2-azo-bisisobutyronitrile (AIBN) as the initiator in 1,4-dioxane solutions. The copolymer products were characterized by IR, 1H-NMR, and 13C-NMR spectroscopic techniques. The reactivity ratios of the monomers were computed by the Fineman-Rose (F-R) and Kelen-Tudos (K-T) methods at lower conversion, using the IR data. The results are in good agreement with each other and the mean reactivity ratios for MMA/EOEMA copolymers are r1=0.8436, r2= 0.7751, and r1r2 = 0.6614. The reactivity ratios indicate the formation of random copolymers, which have been supported by the azeotropic composition evaluations. The distribution of monomer sequence along the copolymer chain has been calculated using a statistical method based on the reactivity ratios. The probability of finding the mean sequence lengths of 2-EOEMA and MMA units has also been evaluated.