Characterization of ADN/GAP‐Based and ADN/Desmophen®‐Based Propellant Formulations and Comparison with AP Analogues

a] 1I ntroductionIn solid propellant rocketry,p ropulsion units in fielded and currently operational missile systems are founded upon ar elatively small number of firmly established propellant technologies, most of which have an extensive historical track record. While propulsion systems with either limited or no restrictions with respect to exhaust plume signature have their basis in ammonium perchlorate (AP) composites with inert binder systems (preferably aluminized), smokeless systems are based on nitrate ester plasticized binders (nitrocellulose, polyethers, polyesters) with or without nitramine filler materials [1].C ombination of the two sorts gives rise to the high-performance propellant types important in domains such as submarine-launched ballistic missiles, applications where performance with regards to specific impulse is particularly critical [2].Although implemented propellant technology has now remained somewhat static for ac onsiderable period of time, new incentives have accelerated the development of new generations of solid rocket propellants. Increasingly stringent legislature associated with the handling and use of many chemical species traditionally used in rocket propellant formulations (heavy metal compounds, perchlorates, isocyanates), when assessed in conjuncture with at ightening export bureaucracy and the diminishing production base for many important raw materials (a result of plant closures and industry consolidation during recent decades), have all contributed to an increased willingness by relevant manufacturers to evaluate new propellant candidates.The bulk of contemporary research efforts directed towards new solid rocket propellant candidates is concentrated around new energetic binder systems and chlorine-free filler materials, as well as associated formulation additives (curing agents, bonding agents, burning rate modifiers) [3-Abstract:G lycidyl azide polymer (GAP) is an important energetic binder candidate for new minimum signature solid composite rocket propellants, but the mechanical properties of such GAP propellants are often limited. The mechanical characteristics of composite rocket propellants are mainly determined by the nature of the binder system and the binder-filler interactions. In this work, we report ad etailed investigation into curing systems for GAP diol with the objective of attaining the best possible mechanical characteristics as evaluated by uniaxial tensile testing of non-plasticized polymer specimens. We started out by investigating isocyanate and isocyanate-free curing systems, the latter by using the crystalline and easily soluble alkyne curing agent bispropargylhydroquinone (BPHQ). In the course of the presented study,w et hen assessed the feasi-bility of dual curing systems, either by using BPHQ and isophorone diisocyanate (IPDI) simultaneously (synchronous dual curing), or by applying propargyl alcohol and IPDI consecutively (sequential dual curing). The latter method, which employs propargyl alcohol as ar eadily available and adjustable hydroxyl...

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Curing of Glycidyl Azide Polymer (GAP) Diol Using Isocyanate, Isocyanate‐Free, Synchronous Dual, and Sequential Dual Curing Systems

Hagen

Jensen

Unneberg

et al. 2014

“…Furthermore, the side reaction occurs between urethane and nitrate‐ester plasticizer . With the concept of “green propellants” , the ammonium dinitramide as new oxidizer is proposed to be used in propellants but it has poor compatibility with isocyanates .…”

Section: Introductionmentioning

confidence: 99%

Combustion Properties of Composite Propellants Based on Two Kinds of Polyether Binders and Different Oxidizers

Gong

et al. 2020

Two kinds of solid propellants based on propargyl-terminated ethylene oxide-tetrahydrofuran copolyether (PTPET) and ethylene oxide-tetrahydrofuran copolyether (PET) were prepared with 1,3,5-trinitro-1,3,5triazacyclohexane (RDX), ammonium perchlorate (AP) and aluminum (Al), respectively. The order of burning rates for PET + RDX, PTPET + RDX and PET + RDX + CuÀ B propellants: PTPET + RDX > PET + RDX > PET + RDX + CuÀ B. Their pressure exponents are also similar when the pressure is higher than 7 MPa. The combustion residue of PET + RDX and PET + RDX + CuÀ B propellants show a loose structure and there are many bright particles distributed in its flame zone. The combustion residue of PTPET + RDX propellant shows a dense structure and its flame is uniform. The burning rates of PET + AP + CuÀ B propellant is between the burning rates of PET + AP and PTPET + AP propellants at the same pressure. Their flame shape is similar. The burning rates of PET + AP + Al + CuÀ B propellant is also between the burning rates of PET + AP + Al and PTPET + AP + Al propellants at the same pressure. The combustion flame of PET + AP + Al propellant differs greatly in direction and shape at different time. The combustion flame of PTPET + AP + Al and PET + AP + Al + CuÀ B become almost identical in shape and direction at different time. These results show that the curing catalyst CuÀ B of PTPET propellant plays a catalytic role in combustion.

“…The decreasing gradient of ADN/AP system was much lower than the other four systems, and the value was decreasing a little but it still remained above 0.9 when AP was totally replaced by ADN. It indicated that as one of the most promising oxidants to replace AP [27][28][29][30], ADN was more effective to improve the oxygen content for low signature propellants.…”

mentioning

confidence: 99%

Enthalpy of Formation of p(BAMO)‐b‐GAP and Energetic Characteristics of Solid Propellants Based on the Copolymer

Chen

et al. 2021

The block copolymer of 3,3'-bis(azidomethy) oxetane and glycidyl azide polymer (p(BAMO)-b-GAP) is an ideal energetic binder for solid propellants. In this work, the enthalpy of formation of p(BAMO)-b-GAP was first investigated by the heat of combustion experimental method and group additivity method. Meanwhile, the energetic characteristics of solid propellants based on the copolymer were systematically calculated. The results proved that the Δ f H of p(BAMO)-b-GAP could be estimated accurately by two methods and the positive Δ f H values were obtained. Dual-oxidant formulas were designed in which AP was re-placed gradually by some chlorine-free high-energy materials. The calculation results showed when AP was gradually replaced by RDX or HMX, the energy level of propellants based on p(BAMO)-b-GAP was improved first but then decreased with AP content further decreased, indicating there was an optimum ratio between AP and its alternative. However, when AP was replaced by CL-20 or ADN, the values of I sp were improved steadily. When less than 40 % AP was replaced, the contribution to the energy level of propellant by RDX or HMX was even more than that by CL-20.