Description:
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
OBJECTIVE: Develop and demonstrate energetic ingredients for polymer resin systems (monomers, plasticizer(s), related additives) for use in explosive and propellant formulations with additive manufacturing capabilities.
DESCRIPTION: The US Army has a need to develop energetic formulations suitable for additive manufacturing (AM) based on printing technologies such as direct-write extrusion and vat polymerization. To enhance the energetic performance and printability of these formulations, new energetic ingredients for AM resin systems are desired. Specifically, these include energetic monomers, crosslinkers, and plasticizers. Although additive manufacturing techniques are largely recent developments, energetic polymers and plasticizers have a relatively long history. Their purpose has generally been as components in chemically cured energetic formulations such as explosive “cast-cure” or polymer-bonded explosives (PBX), where energetic monomers and plasticizers are blended with high-solids loadings of explosive materials (e.g. RDX) and chemically cured into a desired shape/configuration. Existing energetic polymer examples include glycidyl azide polymer (GAP) and poly(3-nitratomethyl-3-methyloxetane) (polyNIMMO). Plasticizer examples include nitroisobutanetriol (NIBTN), bis(2,2-dinitroproplyl) acetal/formal (BDNPA/F), and triethylene glycol dinitrate (TEGDN). In general, these materials often suffer from drawbacks such as poor mechanical properties, stability or sensitivity issues, lower achievable solids-loading, production difficulties, and/or low energetic performance. They were also not developed with next-generation additive manufacturing technologies in mind. Printing techniques such as direct-write extrusion and vat polymerization typically require curable resin systems with appropriate rheological properties, controllable curing and good interlayer adhesion. To both provide higher energetic performance and better align with these AM technologies, new high energy-density, curable polymeric resin materials are required to push the envelope of energetic performance while enhancing stability and improving producibility.
PHASE I: With the goal of working towards one or more complete, curable, high-performance energetic resin system(s), design and determine the technical feasibility for producing novel, AM-applicable energetic resin ingredients to include one or more of the following: energetic monomer(s), energetic polymer(s), energetic plasticizer(s), and/or related additives including photoinitiators and other curatives. Perform theoretical energetic calculations to establish predicted performance and aid in the selection of materials. Develop synthetic approaches to the materials and produce small lab-scale quantities of materials for characterization and safety screening. In addition to strong energetic performance and safe handling, selected materials should be chemically compatible with traditional military explosive ingredients (e.g. nitramines) and munition housing materials (e.g. stainless steel).
PHASE II: Required Phase II deliverables will include the formulation of the identified Phase I energetic polymeric materials into complete chemically-curable energetic resin systems suitable for AM processing. Develop and demonstrate scale-up of down-selected ingredients to the pilot production scale. Evaluate printing of specific parts to demonstrate printability of the resin system. The small business will ship 100 gram samples of the resin system(s) to DEVCOM Armaments Center for verification of product quality and suitability for AM processing.
PHASE III DUAL USE APPLICATIONS: The pilot processes developed in Phase II will be scaled up to the production level. Military applications will focus on explosive and propellant charges. Commercialization areas potentially include the construction, mining, and space industries.
REFERENCES:
1. Provatas, A., Energetic Polymers and Plasticisers for Explosive Formulations—A Review of Recent Advances, Technical Report DSTO-TR-0966, Defence Science and Technology Organisation (DSTO), Aeronautical and Maritime Research Laboratory, Melbourne, Victoria, Australia, April 2000, https://apps.dtic.mil/dtic/tr/fulltext/u2/a377866.pdf;
2. Ligon, S. C.; Liska, R.; Stampfl, J.; Gurr, M.; Mulhaupt, R., Polymers for 3D Printing and Customized Additive Manufacturing. Chem. Rev., 2017, 117 (15), 10212-10290;
3. Desai, H. J.; Cunliffe, A. V.; Hamid, J.; Honey, P. J.; Stewart, M. J.; Amass, A. J., Synthesis and characterization of α,ω-hydroxy and nitrato telechelic oligomers of 3-(nitratomethyl)-3-methyloxetane (NIMMO) and glycidyl nitrate (GLYN). Polymer, 1996, 37 (15), 3461-3469;
4. Straathof, M. H.; van Driel, C. A.; van Lingen, J. N. J.; Ingenhut, B. L. J.; ten Cate, A. T.; Maalderink, H. H., Development of Propellant Compositions for Vat Photopolymerization Additive Manufacturing. Propellants, Explos., Pyrotech., 2020, 45 (1), 36-52.
KEYWORDS: Additive manufacturing, explosive formulation, propellant formulation, energetic plasticizer, energetic polymer
