Determination of primary chemical constituents of PBX(AF)-108 warhead explosive using microPHAZIR™ Near Infrared (NIR) handheld platform

Abstract

An innovative prognostics and health management (PHM) technique for quantifying and characterizing health status of Plastic Bonded Explosive (PBX) Air force (AF) formula PBX (AF)-108 warhead explosive was developed using Near Infrared (NIR) spectra emitted by microPHAZIR™ NIR, a handheld platform developed by Thermo Fisher Scientific. Benchtop High Performance Liquid Chromatography (HPLC) was used as a reference technique for correlation to microPHAZIR™ NIR measurements. Near infrared spectra were acquired from twenty freshly manufactured mixes of PBX (AF)-108 explosive formulae, which were used in setting up a D-Optimal full-factorial design of experiment (DOE). Three-hundred and sixty measurements were recorded and analyzed using Partial Least Squares (PLS) regression analysis for model building and method development. Results were correlated to spectra, which were measured using HPLC reference technique. All recorded measurements performed with microPHAZIR™ handheld platform were successfully validated with HPLC measurements. An algorithm was developed for microPHAZIR™ NIR thus qualifying the platform as a real-time nondestructive test (NDT)/ nondestructive evaluation (NDE) tool for quantification of primary chemical constituents of PBX (AF)-108. Primary chemical constituents of PBX(AF)-108 are Polyurethane (PU) binder, Royal Demolition Explosive (RDX) oxidizer/ fuel, Isodecyl Pelargonate (IDP) plasticiser, and E-702 (4, 4'-methylenebis(2,6-di-tert-butyl-phenol) [MBDTBP] antioxidant/ stabilizer. This teaming effort between Raytheon Missile Systems (RMS), United Kingdom Ministry of Defence (UK MoD), Alliant Techsystems Launch systems (ATK LS), and Thermo Fisher Scientific demonstrated outstanding ability to utilize miniature cutting edge technology to perform realtime NDT of PBX (AF)-108 warhead explosive without generating chemical waste and/or residue. The new technique will further be adapted for use to measure primary chemical constituents of other warhead explosives and solid rocket propellants. The new technique will significantly reduce costs associated with performing ordnance surveillance and Service Life Extension Program (SLEP) assessment, which is often destructive and requires use of lengthy and expensive test techniques described in North Atlantic Treaty Organization (NATO) Standardization Agreement (STANAG)-4170 and Allied Ordnance Publication (AOP)-7 manuals.