THE FORMATION OF ALTERNATING TRIADS AND THE FORMATION OF CIS LINKAGE CONFIGURATION BY A PARTICIPATION OF THE ELECTRON DONOR-ACCEPTOR COMPLEX OF THE MONOMERS IN THE COPOLYMERIZATION OF N-PHENYLMALEIMIDE AND 2-CHLOROETHYL VINYL ETHER^†

Abstract

The ¹³C NMR technique of distortionless enhancement by polarization transfer and quaternary ¹³C NMR are used to quantitatively determine the proportion of alternating triad and the proportion of cis/trans linkage configurations at the cyclic N-phenylmaleimide (PMI) monomer units in the copolymers of PMI and 2-chloroethyl vinyl ether (CEVE), which are prepared by a radical initiator in chloroform solvent at 50°C.

^†Dedicated to the 85th birthday of Professor George B. Butler of The University of Florida.

^*(A former student of Professor George B. Butler.)

The amount of the cis linkage configuration at PMI units is found to be proportional to the amount of alternating CEVE-PMI-CEVE triads in the copolymers; i.e., a relation, (% of cis linkages at PMI units) = (48 ± 5.0%) (mol fraction of CEVE-PMI-CEVE triads), is found in the PMI-CEVE copolymers. It is concluded that the cis linkage configuration is formed predominantly in the process of the formation of the alternating CEVE-PMI-CEVE triads in this copolymerization, and that, according to the Olson-Butler mechanism of a complex participation, 48 ± 5.0% of all the reactions which give CEVE-PMI-CEVE triads is the attack by growing CEVE radicals on the PMI component of an electron donor-acceptor (EDA) complex of the comonomers from the syn direction relative to the CEVE component of the complex. The equilibrium constant K of the 1:1 EDA complexation in chloroform at 25°C is determined to be 0.260 L mol⁻¹ by ¹H NMR spectroscopy.

Acknowledgments

Notes

^†Dedicated to the 85th birthday of Professor George B. Butler of The University of Florida.

^*(A former student of Professor George B. Butler.)