Synthesis and characterization of poly(3,3 bis(azidomethyl)oxetane-co-?-caprolactone)s

The quasi-living cationic copolymerization of 3,3-bis(chloromethyl)oxetane (BCMO) and ε-caprolactone (ε-CL), using boron trifluoride etherate as catalyst and 1,4-butanediol as coinitiator, was investigated in methylene chloride at 0°C. The resulting hydroxyl-ended copolymers exhibit a narrow molecular weight polydispersity and a functionality of about 2. The reactivity ratios of BCMO (0.26) and ε-CL (0.47), and the Tg of the copolymers, indicate their statistical character. The synthesis of poly(3,3-bis(azidomethyl)oxetane-co-ε-caprolactone) from poly(BCMO-co-ε-CL) via the substitution of the chlorine atoms by azide groups, using sodium azide in DMSO at 110°C, occurs without any degradation, but the copolymers decompose at about 240°C. All polymers were characterized by vapor pressure osmometry or steric exclusion chromatography, 1H-NMR and FTIR spectroscopies, and DSC.