Energetic interpenetrating polymer network based on orthogonal azido–alkyne click and polyurethane for potential solid propellant

Abstract

High energetic propellants with synergistic mechanical strength are the prerequisites for aerospace industry and missile technology; though glycidyl azide polymer (GAP) is a renowned and a promising energetic polymer which shows poor mechanical and low-temperature properties. In order to overcome these problems, a novel energetic interpenetrating polymer network (IPN) of acyl-terminated glycidyl azide polymer (Acyl-GAP) and hydroxyl terminated polybutadiene (HTPB) is effectively synthesized and characterized via an “in situ” polymerization by triazole and urethane curing system respectively. Acyl-GAP and dimethyl 2,2-di(prop-2-ynyl)malonate (DDPM) have been synthesized and well characterized by using FT-IR, ¹H NMR, ¹³C NMR and GPC. The maximum tensile strength ∼5.26 MPa and elongation 318% are achieved with HTPB-PU/Acyl-GAP triazole in 50 : 50 weight ratios. The solvent resistance properties have been investigated by the equilibrium swelling method and the glass transition temperature (T_g), morphology and thermal stability are evaluated by DSC, SEM and TGA-DTG respectively. Thus, HTPB-PU/Acyl-GAP triazole is a futuristic binder for the composite solid propellant.