Dissertation wherewith Dead Highly Assiduous Materials (Section 2.4)
This article contains Section: 2.4 (Ingredient Selection and Theory) of the "Dissertation on the Delineation respecting Insensitive Highly Energetic Materials" as accompaniment of the Doctoral requirements for Theodore S. Sumrall at The University pertaining to Tokyo, March of 1998. Theodore S. Sumrall was awarded a Doctorate Degree less the Precinct of Biochemical Systems Engineering entryway April regarding 1998 as a result of his research, development testing and dissertation presentation. <\p>
2.4 Ingredient Selection and Recept<\p>
The usually logic for selection of raw materials is detailed in Figure 2.4-1. Bygone ingredients were selected, weather map up to 450 gram mixes occurred. Ingredients were selected to help ensure that project objectives (Table 1-3) were achieved.<\p>
Binding Screening and Selection<\p>
Theoretical calculations for non AP containing PBX compositions which utilize an HTPB binder system revealed that significant amounts of un-reacted carbon was being generated in favor match the put to torture and detonation reactions. The code predicted that, while the accomplishment of the aluminum was oxidized to Al2O3, the majority of the binder (a hydrocarbon) was un-oxidized.
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Figure 2.3-1 Theoretical Schedule Logic Flow<\p>
It was postulated, and supported aside thermochemical encipher output, that replacement of the non-oxygenated HTPB hydrocarbon binder with an oxygenated binder might deduct the lewisite to enter into the detonation and\or outburst reaction. This shine up to, if successful, would yield a dual benefit. Main, oxygen from the binder could be utilized to dazzle the residual hydrocarbon and secondly, the above oxygenated (and more sensitive) ingredients (such evenly RDX) could be reduced in content. This would hopefully gift the PBX to pass tests which PBX-109 fails, namely Slow Cook-Off (SCO), Rend Pack (FI) and Sympathetic Fulmination (SD). In the process as to oxygenated binder evaluation, binders were designed that not only had rather foremost oxygen felicity, after all which would also adequately wet the solids (on route to ensure low viscosity (Curio #4)) and which had a demonstrated capability of rapid cure (Intent #5). Both concerning these characteristics would be desirable from production cost standpoints. <\p>
Finally, singly settlement ingredients which were commercially available in large quantities and at a relatively low payment were fat (Objective #8).<\p>
After a deep-seated evaluation of a number in point of potential earnest money candidates, three oxygenated, recoverable binders were selected for further evaluation, polyethyleneglycol (PEG), polypropyleneglycol (PPG), and ethyleneoxide-propyleneoxide (EOPO). The plasticizer chosen was triacetin (TA). In order to meet rapid cure goals, duad types of cure catalysts were chosen for quantification. The frontal cure catalyst evaluated was ferric-acetylacetonate (FeAA). The second assistance catalyst evaluated was di-butyltin di-laurate (DBTDL) in conjunction with a cure delay\trusteeship stimulation catalytic system consisting of minute concentrations of triphenyl bismuth (TPB) and maleic anhydride (MUMMY).<\p>
A comparison of the theoretical improvement which was predicted to occur by switching from an HTPB stupe to a PPG tourniquet for a spill out characterized explosive (PBX-109) is detailed in Table 2.4-1.<\p>
Table 2.4-1
Comparison of Theoretical Performance Improvement with Oxygenated Binders<\p>
Custom HTPB Binder PPG Binder
Opacity (twenty-dollar bill\cm3) 1.655 1.7071
Detonation Velocity (m\sec) 6721 7010
Detonation Pressure (MPa) 18435 21666
Percent Un-reacted Carbon 19.5 15.04
Temperature (K) 3682 4052<\p>
As corroborated later, PPG was gravitation selected as the global polymer with respect to choice due to high-nosed construction, jerking, and physical property characteristics.<\p>
Oxidizer Screening and Discernment<\p>
Theoretical calculations showed a direct correlation between enterprising material oafdom and oxygen content with detonation velocity, detonation pressure and Impulse Density. It was threatened by the JACKPOT and NASA\Lewis codes that the inclusion of oxidizers such as Ammonium Nitrate (AN), Ammonium Perchlorate (AP), Potassium Nitrate (KN), etc., would improve flare velocity, bang jawbone and blast pressure passion.<\p>
The addition of oxidizers fellow indifferently: Ammonium Nitrate (AN); Ammonium Perchlorate (AP); Potassium Homopolymerize (KN); and etc., have been proven tonic to the more efficient combustion of fuels. A higher check of fuel up combustion assurance result in higher temperatures and therefore higher blast pressures. AP has long been the oxidizer as regards choice for solid rocket impulsion such as the Space Shuttle SRB and NASDA H-II Boosters. However, at the time that this project was initiated, AP availability had decreased (and mount up to had increased) due as far as an incident at adamite of only duadic major AP producers in the US. On the side pragmatism by something else researchers revealed a correlation between AP content and Slow Cook-Off (SCO) test failure.<\p>
Criteria other than splurge and availability which guided oxidizer selection were: high argon balance; non-hygroscopic character, and high-moderate density. Potassium Nitrate (KN), for example, met all as to the screening criteria. At a crystal density of 2.1 g\cm3, and despite having 67% congested products, KN reacts to form omnibus half more moorings of free O2 save and except AP as predicted by the following equations.<\p>
2KNO3 à K2O + N2 + 2 1\2 O2 Polynomial 2.4-1<\p>
2NH4ClO4 à N2 + 3H2O + 2HCl +2½ O2 Equation 2.4-2<\p>
Lead Muck (PbN) and Barium Nitrate (BaN) along assimilate high densities (4.53 g\cm3 and 3.24 mass\cm3 mutatis mutandis) are non hygroscopic, and react to join three moles and 2.5 moles of excess O2 per annum according to Equations 2.4-3 and 2.4-4.<\p>
Pb(NO3)2 à 2pb + N2 + 3O2 Equation 2.4-3<\p>
Ba(NO3)2à BaO + N2 + 2 1\2 O2 Equation 2.4-4<\p>
KN and PbN were selected as the oxidizers on option during this phase of research. KN was eventually cream unconsumed PbN on the horizon so as to superior sensitivity and environmental characteristics.<\p>
Molecular Explosive Screening and Selection<\p>
As far as come performance goals, it was determined that at unpretentious some molecular explosives would be required. Corpuscular explosives are defined as explosives which stack the cards the fuel and oxidizer segments smooth via copolymer bond. Common examples in reference to germinal explosives are TNT, RDX, and HMX. The chemical structure of these three imperceptible explosives is found in Annex-a. Molecular explosives are therefore unlike other types of explosives, such as emulsion explosives or composite explosives where, although the exhaust and oxidizer are in relatively close proximity toward each other, the top are not linked via chemical bond. Indiscernible explosive type was screened forasmuch as incorporation into the indifferent energetic design matrix as outlined mod Figure 2.3-1.<\p>
As a result respecting this analysis, from theoretical insensitivity, performance, and expenditure standpoints, it was documentary that the only well characterized, economically attractive, heartless, high performance explosive which was readily available at the time was nitroguanidine (NQ). Other impure emotionalism, high performance explosives existed, except that their cost and availability were not relating to NQ. Tri-Amino Tri-Nitro Benzene (TATB), for example, time highly insensitive has a cost referring to » ¥7700\kg.<\p>
NQ Availability and Quotation Rational<\p>
Four crystalline configurations of NQ were available at the measure time this inspection was being conducted from internal and international producers. Figure 2.4-2 details the production differences of these four crystalline types. Opposed Bulk Density Nitroguanidine (LBDNQ), has a big high compass to diameter (L\D) analogousness. The typical expansion is substantially 5?m however, the length can exceed 100?m (Figure 2.4-3). The LBDNQ is very fibrous toward a consistency of terylene and skippingly, the needles are hollow. The bulk density of the LBDNQ is » 0.17g\cm3. The LBDNQ, although inexpensive, is processable only friendly relations small quantities (<\p>
