Approximately 100 million pounds of energetic materials waste, or 41 percent of the total life-cycle energetic waste production, is generated during manufacture. An additional 449,000 tons of energetics waste is produced during demilitarization. Research needs to be conducted to define the environmental impact of energetic materials.

The following are the objectives of this program: (1) assess the environmental issues associated with energetic materials to identify major areas of concern for future research and development investments, (2) demonstrate technologies that utilize liquid or super critical carbon dioxide and enzymes to synthesis energetic materials, and (3) demonstrate the use of models and databases for the design and development of gun propellants that meet environmental and performance requirements.

The project consists of four primary tasks. The first task is to complete a study to determine the environmental technology needs of the military energetic materials community. The second task is to test model-based gun propellant formulations (1) to determine whether the candidate propellants satisfy naval standards and (2) to predict the volatile organic compound (VOC) processing emissions for these propellants. The third task is to demonstrate proof-of-principal testing for the use of the enzymes in place of organic solvents in the synthesis of energetic materials. The following four target ingredients were chosen: DNDMB (2,3-dimethyl-2,3-dinitrobutane), a taggant for plastic explosive formulations; HNS (2,2,4,4,6,6- hexanitrostilbene), a heat-resistant explosive ingredient used in aircraft ejection seats; BT (1,2,4-butanetriol), a precursor of BTTN and a plasticizer used in Department of Defense (DoD) propellants and explosives; and DNPOH (2,2- dinitropropanol), a precursor of a plasticizer used in automobile airbags and DoD propellants and explosives. Task four will be the preparation of nitramine oxidizers, nitrate ester polymers and plasticizers, and BAMO/AMMO thermoplastic elastomer in liquid carbon dioxide solvent.

An energetic materials environmental study was completed with participation from all three Services, NASA, the Environmental Protection Agency, and others. It identified eleven areas for which SERDP might consider promoting future research and development work.

The following three candidate propellant formulations met the lead-free and performance requirements sought: a M1A1 double base propellant, a EX99 low-vulnerability ammunition propellant, and an RDX/TPE (thermoplastic elastomer) formulation.

Using commercial software (Extend), the propellant cost for each manufacturing activity was calculated. For a 200- pound plant run, the environmental costs of RDX/TPE and EX99 were 5 percent and 20 percent of the total cost, respectively. The yield of existing DNDMB synthesis is about 10 percent. The Naval Surface Warfare Division at Indian Head, MD, has demonstrated 60 percent yields of DNDMB from the oxidative coupling of two 2-nitroprpoane molecules catalyzed by peroxidase. This project was completed in FY 1999.

This project would (1) provide ways to utilize waste energetic materials, formulate green gun propellants, and manufacture ingredients used in propellants and explosives without the use of VOC solvents (by using liquid carbon dioxide or enzymes) and (2) demonstrate the manufacture of thermoplastic elastomers and energetic ingredients in an agile plant.