Abstract: The search for a smokeless propellant has encouraged scientists and engineers to look for a chlorine-free oxidizer as a substitute for AP (ammonium perchlorate). Endeavors seemed to come to an end when ADN (ammonium dinitramide) appeared in the West in the early 1990s. Although some drawbacks soon became apparent by that time, the foremost obstacle for its use in rocket-motors came from the patent originally applied for in the United States in 1990. Furthermore, environmental concerns have also increased during these two decades. Ammonium perchlorate is believed to cause thyroid cancer by contaminating soil and water. In addition, AP produces hydrogen chloride during burning which can cause acid rain and ozone layer depletion. Unlike AP, ADN stands for both smokeless and green propellant. Since then, much progress has been made in its development in synthesis, re-shaping, microencapsulation and solid propellant. The high solubility of ADN in water has also allowed its application as liquid monopropellant. Tests have revealed Isp (specific impulse) superior to that normally observed with hydrazine, one of the most harmful and hazardous liquid propellants. With constraints of use, along with the patent near to expiry, scientists and engineers are rushing to complete developments and patents until then.

Abstract: Synthesis and characterization of energetic ABA-type thermoplastic elastomers for propellant formulations has been carried out. Following the working plan elaborated, the synthesis and characterization of Poly 3-bromomethyl-3-methyl oxetane (PolyBrMMO), Poly 3- azidomethyl-3-methyl oxetane (PolyAMMO), Poly 3,3-bis-azidomethyl oxetane (PolyBAMO) and Copolymer PolyBAMO/AMMO (by TDI end capping) has been successfully performed. The thermoplastic elastomers (TPEs) were synthesized using the chain elongation process PolyAMMO, GAP and PolyBAMO by diisocyanates. In this method 2.4-toluene diisocyanate (TDI) is used to link block A (hardandmono-functional)) to B (soft and di-functional). For the hard A-block we used PolyBAMO and for the soft B-block we used PolyAMMO or GAP. This is ajoint project set up, someyears ago, between the Chemistry Division of the Institute of Aeronautics and Space (IAE) - subordinated to the Brazilian Ministry of Defense - and the Fraunhofer Institut Chemische Technologie (ICT), in Germany. The products were characterized by different techniques as IR- and (1H, 13C) NMR spectroscopies, elemental and thermal analyses. New methodologies based on FT-IR analysis have been developed as an alternative for the determination of the molecular weight and CHNO content of the energetic polymers.

Azide polymers samples were analyzed by FT-MIR in order to develop a quantitative methodology to determine the C, H and N content in energetic polymers used in propellants. The elemental analysis data were used as reference. The FT-MIR results show a good agreement with CHN analysis. A good linear relationship was obtained suggesting that the methodology developed in the CTA laboratory can be used for quality control of these energetic polymers.