Model copolymerization reactions. Initiation of the copolymerization of methyl methacrylate and acrylonitrile by 1,1′-azobis(1-phenyl[1- 13C]ethane)

Abstract

The copolymerization of methyl methacrylate (MMA) and acrylonitrile (A) was initiated by photolysis of 1,1′-azobis(1-phenyl[ 13C]ethane) (1) at 33°C in benzene. Determination of relative endgroup concentrations in the resulting copolymers allowed determination of the relative rates of addition of MMA and A to the 1-phenylethyl radical derived from 1. We find k MMA/ k A = 0.44 ± 0.03, a value consistent with known copolymerization behavior. Further analysis of 75 MHz 13C NMR spectra led to the determination of k MMA/ k A for the 2-(4-phenylpentanenitrile) radical derived from primary radical addition to A. The measured value of k MMA/ k A supports only one of five reported studies of the radical copolymerization behavior of MMA and A.