Determination of the reactivity ratios, sequence distribution and stereoregularity of butyl acrylate-methyl methacrylate copolymers by means of proton and carbon-13 NMR

The 400 MHz proton NMR spectra of Bu acrylate (BA)-Me methacrylate (MMA) copolymers prepd. by free radical polymn. in soln. at 323 K were used for the detn. of the reactivity ratios. The reactivity ratios rM and rB calcd. by the error-in-variables method are 2.279 and 0.395, resp. The methoxy region of the MMA proton signal resonance was found to be sensitive for MMA-centered sequences and a new assignment is proposed. The coisotacticity parameter sBM was calcd. using a nonlinear least-squares procedure with relative error estn. 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-centered configurational sequences. The same assignment is used as for the Et acrylate-Me methacrylate copolymer