In order to investigate the radical ring-opening polymerization of 4-membered cyclic monomers, β-vinyl propiolactone was prepared and its homopolymerization and copolymerization with common radically active monomers were attempted.
Homopolymerization was carried out by thermal (2,2'-Azobisisobutyronitrile, Benzoyl peroxide), photochemical (Benzophenone, Benzoin methyl ether), and organic redox initiators. However all the attempts have failed to give polymerization products.
Copolymerization was also carried out with styrene and with MMA by and AIBN, BPO as initiators. However, again copolymerizations failed to incorporate significant amount of β-vinyl propiolactone into copolymers.
These results show that β-vinyl propiolactone is stable toward radical attacks. At elevated temperatures above 60℃ thermal decomposition of β-vinyl propiolactone became serious. Further activation of propiolactone moiety by proper substitution may be necessary for the successful radical opening.