Fluoroalkylated-GAP copolymers (GAP-FP) as promising energetic binders

Abstract

The development of a novel energetic block copolymer of glycidyl azide polymer (GAP) and fluoropolymer (FP) using a boron trifluoride-tetrahydrofuran complex/diol initiator system is reported herein. Well-defined compositions of the GAP-FP copolymers in two different GAP to FP ratios (1:1 and 1:3) were synthesized by tailoring the desired molecular weights of each block in the copolymer, demonstrating the synthetic versatility of such a copolymer system. The resultant GAP-FP copolymers represent a unique hybrid binder system with tunable energy releasing and oxidizing potentials intended for metallized formulations. Thermogravimetric analysis showed that the carbonaceous residue usually formed from the decomposition of GAP could be reduced significantly by the copolymerization with FP. Isoconversional method of kinetic analysis of the GAP-FP copolymers revealed an increasing dependence of the effective activation energy on the extent of conversion. The increasing dependence suggested a mechanism of the competing reactions that were found to be between the reactions of FP triggered oxidation and intermolecular crosslinking of the polyimine intermediates formed from GAP decomposition that ultimately resulted in the reduction of the carbonaceous residue.