Abstract: | Acrylonitrile–styrene–methyl methacrylate (A–S–M) terpolymers were prepared by photopolymerization using uranyl nitrate ions as photo initiators, which were analyzed by NMR spectroscopy. The terpolymer compositions were determined by Goldfinger's equation using comonomer reactivity ratios: ras = 0.04; rsa = 0.31; ram = 0.17, rma = 1.45; rsm = 0.52; rms = 0.47. The terpolymer compositions were also determined from the quantitative 13C(1H)‐NMR spectroscopy. The sequence distribution of the acrylonitrile‐, styrene‐, and methyl methacrylate–centered triads were determined from the 13C(1H)‐NMR spectra of the terpolymers and are in good agreement with triad concentrations calculated from the statistical model. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3026–3032, 1999 |