Living cationic ring-opening polymerization of 3,4-dihydro-2H-benzo[4,5]imidazo[2,1-b]oxazine

The cationic ring-opening isomerization polymerization of 3,4-dihydro-2H-be nzo[4,5]imidazo[2,1-b]oxazine (DBI) is reported for the first time. The pol ymerization of DBI with methyl trifluoromethanesulfonate proceeds smoothly at 35 degrees C and gives poly(2,3-dihydro-1H-benzo[d]imidazol-2-one-1,3-di yltrimethylene) (polyDBI) in high yield. The narrow molecular weight distri bution of the product as well as the results of postpolymerization revealed that the polymerization proceeds in a living fashion. PolyDBI is an amorph ous white solid whose T-g determined by DSC is 31 degrees C. TGA analysis s howed that it is stable up to 475 degrees C in nitrogen atmosphere.