| Abstract: | 1-Methyl-3-methylenecyclobutene (MMCB) and 1,2-dimethylenecyclobutane (DMCB) copolymerized readily with isobutene with aluminum chloride as initiator in methyl chloride solution at temperatures from ?95 to ?78°C. No polymers were obtained with methylenecyclobutene (MCB) under similar conditions. The copolymerization of MMCB with isobutene took place through a 1,5-addition reaction while that of DMCB through both 1,2- and 1,4-addition reactions. Large amounts of gel were present in the copolymers obtained from DMCB if the reaction was carried to high conversion. The commonly observed effects of dienes (i.e., rate retardation and molecular weight depression) on cationic copolymerization reactions were observed but to a much higher degree with these small ring dienes. The thermal crosslinking behavior of the resulting copolymers was investigated. In conjunction with the copolymerization studies, homopolymers of MMCB, DMCB, and 3,3-dimethyl-1-isopropylidene-2-methylenecyclobutane (IMCB) were prepared and their chemical structures examined. |
