Stereochemical Evidence for Participation of a Donor-Acceptor Complex in Alternating Copolymerization. 2. Copolymer Structure

Abstract

Various N-substituted maleimides have been shown to alternately copolymerize with several vinyl ethers. The stereochemistry of these copolymers, as deduced from 13C NMR spectroscopy, is markedly dependent on such copolymerization conditions as temperature, solvent, total monomer concentration (MT), comonomer concentration ratio at fixed total monomer concentration, and the donor-acceptor character of the comonomer pair. Copolymerization conditions favoring the formation of a comonomer donor-acceptor complex (DA) invariably gave higher cis:trans stereochemical ratios at the succinimide units in the resulting copolymers. The results are interpreted as indicating that copolymer succinimide unit stereochemistry is dependent on the fraction of maleimide monomer in complex form and that the DA participates significantly in the propagation steps of the copolymerization. © 1984, American Chemical Society. All rights reserved.