DETERMINATION OF THE REACTIVITY RATIOS, SEQUENCE DISTRIBUTION AND STEREOREGULARITY OF BUTYL ACRYLATE-METHYL METHACRYLATE COPOLYMERS BY MEANS OF PROTON AND C-13 NMR

The 400 MHz proton NMR spectra of butyl acrylate (BA)-methyl methacrylate (MMA) copolymers prepared by free radical polymerization in solution at 323 K were used for the determination of the reactivity ratios. The reactivity ratios r(M) and r(B) calculated by the error-in-variables method are 2.279 and 0.395, respectively. The methoxy region of the MMA proton signal resonance was found to be sensitive for MMA-centred sequences and a new assignment is proposed. The coisotacticity parameter sigma(BM) was calculated using a non-linear least-squares procedure with relative error estimation based on the new assignment and was found to be 0.39. The carbon-13 NMR spectra of the BA-MMA copolymers, in particular the carbonyl signal resonances, are sensitive for MMA- and BA-centred configurational sequences. The same assignment is used as for the ethyl acrylate-methyl methacrylate copolymer.