The free-radical homopolymerization and copolymerization behavior of N-(2-methylene-3-butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 degreesC for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels-Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2'-azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be R-p proportional to [AIBN](0.507)[M](1.04), and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4-structure that included both 1,4-E and 1,4-Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 degreesC with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r(1) = 6.10 and r(2) = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. (C) 2003 Wiley Periodicals.