Determination of the sequence distribution and stereoregularity of ethyl α‐benzoyloxymethylacrylate—methyl methacrylate copolymers by means of proton and carbon‐13 NMR

Abstract

Proton and Carbon-13 NMR spectra of ethyl α-benzoyloxymethylacrylate (E)–methyl methacrylate (M) copolymers were analyzed in terms of sequence distribution and stereoregularity of monomer units. The copolymers were prepared by free radical polymerization in benzene at 50°C. The methoxy region of the M proton signal resonance was found to be sensitive to the copolymer composition for M-centred sequences. The carbon-13 NMR spectra of the EM copolymers, in particular the carbonyl signal resonances of carbomethoxy and carboethoxy groups, are discussed in terms of M- and E-centred configurational sequences. The experimental values were in excellent agreement with those calculated taken into account the terminal copolymerization model and Bernoullian distribution of stereoregularity with the statistical parameters determined from reactivity ratios rE = 0.32 and rM = 1.34 and the coisotacticity parameters σMM = 0.22, σEE = 0.70, and σME = σEM = σ = 0.30. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3483–3493, 1997