Synthesis and characterization of a novel azido fluoroalkyl oligoether energetic plasticizer

Abstract

Cast cured formulations have emerged as an important enabling platform for the manufacturing of large calibre energetic systems. In this study, we report a novel hybrid oligomer containing fluoroalkyl and azido moieties, 1,4-bis((2-azido-4,4,5,5,6,6,7,7,7-nonafluoroheptyl)oxy)butane (BANFHOB) as an energetic plasticizer for a cast curable fluoropolymer (FP) binder. The fluoroalkyl and azido groups impart oxidizing and energy release properties to the plasticizer. BANFHOB was synthesized by cationic ring-opening polymerization of 2,2,3,3,4,4,5,5,5-nonafluoropentyloxirane, followed by end-group modification of the terminal hydroxyl groups into azides. BANFHOB with a number average molecular weight of 698 g/mol exhibited low glass transition temperature (Tg = –78.2 °C) and viscosity (η25°C = 71 mPa s). Compared to a conventional plasticizer (dibutyl phthalate), BANFHOB showed good miscibility with FP and exhibited excellent plasticizing effects by significantly reducing the Tg and viscosity of FP. BANFHOB also exhibited promising plasticizing effects on a commercial fluoropolymer binder (Viton®), demonstrating its application potential for fluoropolymer-based formulations.