Synthesis of glycidyl azide - γ-butyrolactone random copolymer (BL-ran-GA) and investigation of kinetic parameters

In this research, a glycidyl azide–γ-butyrolactone random copolymer (BL-ran-GA) was synthesized through a two-step process. First, a BL-ran-ECH copolymer was prepared via cationic ring-opening polymerization of epichlorohydrin and γ-butyrolactone. Then, azidation was performed to obtain BL-ran-GA with a molecular weight of 782 g·mol–¹. Structural characterization was carried out using FT-IR, 1H and 13C NMR spectroscopy, and GPC. Thermal behavior was analyzed via DSC and TGA-DSC. Key synthesis parameters, including temperature and reaction medium, were optimized. The best conditions involved bulk polymerization at ambient temperature for 168 hours using BF₃·OEt₂ as catalyst. The glass transition temperature (Tg) of the copolymer decreased from -48.00°C (GAP) to -67.7°C (BL-ran-GA), indicating improved thermal flexibility. Activation energy (Ea) for thermal decomposition was calculated using Kissinger and Flynn-Wall-Ozawa methods, yielding values of 103.88 and 107.03 kJ·mol–¹, respectively. These results demonstrate enhanced thermal stability compared to pure GAP. In conclusion, the BL-ran-GA copolymer presents a promising approach to improving the properties of glycidyl azide polymers for energetic applications.