Radical polymerization of a five-membered cyclic carbonate with an exomethylene moiety, 4-methyl ene-5,5-dimethyl-1,3-dioxolan-2-one, was examined. The polymerization proceeded via both vinyl-type and decarboxylative ring-opening processes to give an oligomer with carbonate and ketone structure, which may be crosslinked with P-xylylenediamine
