Studies on the microstructure of vinyl/<TOGGLE>N</TOGGLE>-phenylmaleimide copolymers by NMR and their applications

The micro- and stereostructures and sequence distribution of methyl methacrylate (MMA)/N-phenylmaleimide (PMI) and styrene (St)–PMI copolymers were studied in detail with NMR spectroscopy. The MMA–PMI copolymer was in a random sequence distribution and the St–PMI copolymer was alternating in structure. Some micro- and stereoinformation of the MMA–PMI copolymers could be obtained from ¹H-NMR spectra. The average number sequence length obtained from the copolymer triad by ¹³C-NMR spectra was in agreement with that calculated from the reactivity ratios measured by an elemental analyzer. From the triad fraction of the copolymer measured by ¹³C-NMR, the copolymer chain of MMA–PMI was proved to be a one-order Markov chain. More suitable propagation reactions were proposed from the deviation of sequence distribution of the St–PMI copolymer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2581–2587, 2000