Alternating Copolymers from trans-1, 2-Dibenzoylethylene and trans-1, 2-DiacetylethyIene

Abstract

Symmetrical α, β-unsaturated carbonyl compounds, trans-1, 2-dibenzoylethylene (DBE) and trans-1, 2-diacetylethylene (DAE) were synthesized and copolymerization with styrene or n-butyl vinyl ether was carried out in the presence of a radical initiator. The apparent over-all rates of the copolymerization of DBE were faster than that of DAE and the addition reaction of DBE with amine was also faster than that of DAE, indicating that the double bond of DBE is more electron-deficient than DAE.The compositions of copolymers from DBE or DAE were constant at the molar ratio of 50 mol%, regardless of the monomer ratios in the feed, although DAE did not copolymerize with n-butyl vinyl ether. No evidence could be found from spectroscopic studies for the formation of a charge-transfer complex between DBE or DAE and donor monomers, and the alternating tendency of the copolymerization could be increased by the strongly favorable polar effect of two carbonyl groups on the double bond of DBE or DAE.Neither DBE nor DAE copolymerized with styrene with an anionic initiator, possibly because they formed anions too stable to initiate copolymerization.