Synthesis and thermal decomposition of 3,3'-bis-azidomethyl oxetane-3-azidomethyl-3'-methyl oxetane random copolymer

We synthesized a 3,3'-bis-azidomethyl oxetane-3-azidomethyl-3'-methyl oxetane random copolymer [poly(BAMO-r-AMMO)] using the borontrifluoride-dimethyl ether complex/diol initiator system. Hydrogen nuclear magnetic resonance (¹H NMR) was used to analyze the composition of the synthesized copolymer. The results indicated that the composition of the copolymer is in accordance with the molar feed ratio of the monomers. Thermogravimetric analysis (TGA) was used to study the thermal decomposition behavior. The main weight loss step in poly(BAMO-r-AMMO) coincides with the exothermic dissociation of the azido groups in the side chain. In poly(BAMO-r-AMMO), it appears that the other weight loss step is due to the decomposition of the polymer backbone. Kinetic analysis was performed by Vyazovkins model-free method. Based on the activation energy data, the random copolymer should form a reticular structure with chemical cross-linking points after the exothermic dissociation of the azido group. Using simultaneous TG-IR-MS data, it was confirmed that this process is controlled by the competitive reactions of intramolecular cyclization and intermolecular cross-linking.