This work developed the cationic ring opening polymerization of 3 methyl 3 hydroxymethyleneoxetane initiated by BF 3·OEt 2 directly. The resulted polymer was easily dissolved in polar solvents such as CH 3OH, C 2H 5OH, DMSO and N methyl pyrrolidone, but not dissolved in water, tetrahydrofuran and other non polar solvents. The TGA study of sample 1 indicates that the polymer starts to pyrolyze at 360 ℃. There is a melting endotherm at 125.9 ℃ in the DSC curve of sample 1, and the melting peak enlarged with decreasing the amount of catalyst added, which means that sample 1 is essentially linear, and with increasing the amount of catalyst the resulted polymer becomes slightly branched.
