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Copolymerization of two bromine containing methacrylate monomers with methylmethacrylate. Determination of reactivity ratios by in situ quantitative 1H NMR monitoring

Abstract An important method used to make medical implants radiologically visible is based on introduction of radiopaque bromine or iodine containing methacrylic monomers. Thus, 2-(2-bromopropionyloxy) propyl methacrylate (BPPM) and 2-(2-bromoisobutyryloxy) propyl methacrylate (BIPM) were synthesized with the aim to use them as radiopaque agents. The free radical initiated copolymerization of BPPM and BIPM with methyl methacrylate (MMA) were performed directly in a thermostatic cell of the NMR spectrometer. The copolymer compositions obtained from 1H NMR spectra led to the determination of the reactivity ratios (rMMA = 1.08 ± 0.12; rBPPM = 1.01 ± 0.13 and rMMA = 0.95 ± 0.09; rBIPM = 0.95 ± 0.1). The reactivity ratios of these two monomers is similar to that of MMA suggesting that the length of the bromine containing monomers side chain does not affect significantly the reactivity of the methacrylic double bond. From the results we conclude the copolymers to have random structure.