13C-Nuclear Magnetic Resonance Analysis of Some Essentially Random Copolymers of Methyl Methacrylate and Butadiene

Abstract

Abstract 20 MHz 13C-NMR (nuclear magnetic resonance) spectroscopy has been used to determine the relative concentrations of certain methacrylate and butadiene containing monomer sequence fractions in some essentially random free-radical copolymers of methyl methacrylate and butadiene. Several of the results are in good agreement with those obtained in an earlier 1H-NMR study and confirm, within experimental error, that the copolymeriza-tion obeys first-order Markov statistics. The patterns of olefinic carbon resonances reveal that the progressive introduction of methacrylate units into the polymers slightly increases the trans-1,4- to cis-1,4 ratios of the butadiene units relative to that found for a pure polybutadiene prepared under similar conditions.