Rapidly Defluorinated Difluoramino-Rich Binder Synthesized via Selectfluor: Enhancing Combustion Efficiency of Metal Fuels for High-Energy Propellants

Difluoramino (NF2) materials have attracted extensive attention as promising high-energy components for advanced propellant systems. Recent research efforts have primarily focused on developing effective strategies to obtain difluoramino-rich materials, given their significant potential for enhancing the combustion performance of propellants. However, challenges remain in the limited synthesis and application in propellant formulas, owing to their hazardous synthetic routes and poor processing performance. Herein, we report a difluoramino-rich polyether binder, poly-3-difluoraminomethyloxetane (PDFAO), synthesized using Selectfluor as a safe fluorinating agent. PDFAO exhibits a higher fluorine content (29.93%) than the conventional difluoramino binder, poly-3-difluoraminomethyl-3-methyloxetane (PDFAMO), while maintaining exceptional processability. Density functional theory (DFT) calculations and thermal analysis confirm that PDFAO exhibits more rapid fluoride release. Comparative ignition and combustion tests of metal/binder systems reveal that the PDFAO-based composite achieves a ∼10% reduction in ignition delay and a >100% increase in flame intensity compared to PDFAMO. Furthermore, when integrated into ammonium perchlorate (AP)-based formulations, the optimized PDFAO systems delivered optimum flame intensity and peak pressure. These results demonstrate that PDFAO significantly enhances metal combustion efficiency, highlighting its potential for high-energy propellants.