Propellants centralite

Many methods have been proposed and are used to study the thermal stability of propellants and to ensure the absence of possible autocatalysed decompositions during storage. None are sufficiently reliable to merit individual description. In practice, stabilisers are added, the usual being diphenylamine for nitrocellulose powders and symmetrical diethyl diphenyl urea (carbamate or centralite) for double base propellants. Provided a reasonable proportion of stabiliser remains, the propellant can be assumed to be free from the possibility of autocatalytic decomposition. The best test of stability is therefore a chemical determination of the stabiliser present. 

M8 propellant 52.15% nitrocellulose/43% nitroglycerin/ 3% diethyl phthalate/1.25% potassium nitrate/0.6% ethyl centralite... 

Propellants were especially susceptible to spontaneous ignition before it was learned how to stabilize the NC. This was done by including substances called stabilizers in the propellant formulations. These substances, such as diphenylamine, centralite etc absorb the nitrogen oxides as they are formed, thus removing them from the sphere of reaction. This prevents further decomposition and the rise in temperature which decomposition produces. 

Propellant with Nitroacetylcellulose). There are 860 960 calorie-types, which contd, respectively NG 27 32, Nitroacetylcellulose (N 11.2%) 66 63, Centralite 7 4 and DPhA 0 1% used in cal 20 37mm cannons (Ref 11, p 147 ... 

A. Polveri alia sola nitrocellulosa a solvente volatile o Polveri a una base (Single Base Propellants with Volatile Solvent). To these belong a proplnt listed by Giorgio, p 205 as Polvere italiana per cartucce cal 8 per mitragliatrice, which contd NC (12.8% N) 97, Centralite 2... 

C. Polveri a piu componenti (Propellants with Several Components). Giorgio (Ref 26) lists on p 207 among them some propellants which are listed by Belgrano on p 206 under Polveri a solvente fisso. One of them, Polvere alia Centralite, lsited by Giorgio on p 207, was not found in Belgrano. Its compn is NG 24, NC 69 Centralite I 7%... 

Gelatinizers and Stabilizers for Smokeless Propellants. Giua Guastalla (Ref) listed the following compds proposed by them aniline, Centralite, DPhA (Dipheriylamine), phthalide, o-naphthylurethaoe, ethyl oxanilate (CeH,6.NH-COOC2H.5) and potassium oxanilate... 

Smokeless propellants may be taken as another example of composite explosives. These may be either mixtures of nitrocellulose of differing degrees of nitration, partly in a colloidal and partly in a fibrous state with an admixture of the remaining solvent and a stabilizer or a solution of nitrocelluloses in carbamite (centralite) and nitroglycerine with an admixture of components such as aromatic nitro compounds, nitroguanidine, graphite etc. 

G. Sifre, MP 3 5, 374-79(1953) (Polaro-gaphic detn of DPhA in proplnts in presence or absence of Centralites) 21) A.H. Cast el Li et al, PATR 2094(1954), "Diphenylamine, Di-butylphthalate and Dinitrotoluene Dete rmina-tion in Ml and M6 Propellants by IR Method"... 

Cohen, Test Report T62-15-1, June 1962, Frankford Arsenal, Philadelphia, Pa, "Determination of Admixture of Diphenylamine and Ethyl Centralite in. Propellants". This method is described in Vol 2 of Encycl, pp Cl32 ... 

Stabilizer Carbamite (diphenyl diethyl urea), methyl centralite (diphenyl dimethyl urea), chalk and diphenylamine Increase shelf life of propellant... 

Method 1 (when only acardite I is present and no urethanes, DPhA or centralites) a)Extract with chloroform or methylene chloride(5—lOg) a finely divided propellant using a Soxhlet... 

Method 2(when acardite 1 and a centralite are present) a)Extract the finely ground sample of propellant, as in Method 1, evaporate the solvent and weigh the dry residue (wt 1), which is equal to centralite acardite b) Treat the residue with aq AcOH at pH ca 4. This will hydrolize the centralite, leaving acardite I intact c)Wash the residue with w, dry, and weigh(wt 2). Wt 2 is equal to acardite 1 and wt 1 — wt 2 is equal to centralite a) Det mp of acardite 1 and if ca 189°, no further analysis is necessary e)If mp is not Ig0°. detn the amt of acardite either by direct bromination, proc(d)of Method 1 or by the method of Dalbert Tranchant(Ref 3)... 

Method 3(when acardite II centralites are present) a)Extract with chlf or methylene chloride ca lOg of finely divided propellant, evap the solvent and weigh the dried extract (wt 1 - centralite + acardite II) b)Treat the extracted material with aq AcOH at pH ca 4 and filter the mixt through cared sintered glass crucible. Rinse the residue, dry it to const wt and weigh(wt 2 = acardite II and wt 1 — wt 2 centralites) c)Continue. the analysis as described in procedures (c) to (g) of Method 4... 

ACT 5 (Ardeer Cordite Tubular No 5)- A batch No 320B delivered in 1938 for the Brazilian Navy had to meet the following specification requirements NC(N= 11.8 +0.2) 65.0 +1, NG 29.0 + 1 and centralite 6.0 +0.5% Graphite could be added to the extent of 0. 2% and max moist content of ACT 5 was 1% Ref Adm Alvaro-Alberto, Rio de Janeiro private communication Oct 14, 1958 ACT 5, Erosion of. The erosive action of ACT 5 as well as of some other propellants was investigated in Brazil by Admiral Alvaro-Alberto (Ref 2) from the point of view of Vieille s erosion theory (Ref 1). This theory was modified using some later data of Muraour and of other investigators. A brief resume of Alvaro-Alberto s work on erosive action of propellants is given in CA 40, 2629-30(1946)... 

Kirk Othmer 11 (1953), 777 stated that AN can be used as an oxidizer in rocket propellants in place of K perchlorate V)Warren (1958), p 1 lists a solid rocket propellant consisting of AN 80, elastomeric binder 18 additives 2%. He also discusses on pp 34-5 the use of AN as an oxidizer in rocket propellants W)Dr L.Deffet, Belgium listed in private communication, 10 March 1954,the following AN expls as currently manufd in Belgium Alkalite, Alsilite, Centralite TA, Cooppalite Dynamite III, Flammivore,... 

Available Stabilixer (Diphenylamine and/or Ethyl Centralite) in Aged or Stored Propellants is determined by Method 217.2(T) listed in specification MIL-STD-286... 

PATR 2488(1958)(New formulas for rapid calcn of linear burning rates of solid proplnts) 32)J. Delacarte et al, MP 41, 223 65(1959)(Contribution to study of rates of burning and other props of composite proplnts) 33)J Taylor, "Solid Propellant and Exothermic Compositions , Interscience, NY(1959), 55-6 34)C.Napoly, MP 42, 229-46(1960)(4 refs)(Relations between linear rate of burning, apparent potential and pressures for proplnts consisting of only NC, NG and Centralite) 35)Anon, "Ordnance Proof Manual , Aberdeen Proving Ground, Md,7-24 36)L.Shulman et al, PATR FRL-TR 41(1961)... 

K nitrate 0.7 Centr 6.0, graphite 0.3, residual ale 1.2 residual water 0.3%(CS Spec OAC-PD-134)(See also Centralite 1, Analytical Procedures Centralite 1, Nitro Derivatives of) and Centralite 1, Transformation Products, Formed During Aging of Propellants Containing It)... 

US Military Standard MIL-STD-286A(196l) (Propellants, Solid Sampling, Examination and Testing) Method 202.2.2(Detn of EtCentr in newly manufd proplnts) Method 217.2. l(Detn of available stabilizer in aged proplnts) 35)PATR 2700 Vol 1(1960), pp A516 Sc A674 36)US Joint Army-Navy Specification JAN-E-255 [Ethyl Centralite(Carbamite)] 37)J.Apatoff J.Cohen, "Determination of Admixture of Diphenylamine and Ethyl Centralite in Propellants ,Test Report T62-15-1, Frankford Arsenal, Philadelphia, Pa (1962)... 

Centralite 1 Transformation Products Formed During Aging of Propellants Containing It. 

VOHydrolyzable Matter - shall be absent when tested as described under Centr 1 VII)Particle Size. Class 2(powder)-a min of 100% of the material shall pass thru US Std No 50(297 micron) sieve conforming to US Spec RR-S-366. The test is conducted in the same manner as described for Centr I Determination of Centralite 2 in Propellants may be conducted as described in Methods A and B under Centralite 1, Analytical Procedures, except that the formulas for calcns are different and are given under Centr 1... 

J.B. Eldridge, Solid Propellant Mixtures , USP 3951706 (1976) CA 86, 65360 (1976) [The inventor claims that by modifying a doublebase proplnt (30—50%) by addn of a castable plastisol (nitrasol) binder (50—70%), with or without oxidizer and fuel, a castable solid pro-pint having improved and controllable burning characteristics over both types of propints is formed. Thus, a mixt of NC 22.8 and ethyl centralite 1.2 is blended for 30 mins with Petrin 96 and then, successively, AP 60 and atomized A1 30g are added. To this mixt is added 90g of 30 mesh double-base proplnt termed X-12 (consisting of NC 50, NG 38, DPA 59, 2-nitro-diphenylamine 2, Pb-j3-resorcylate 2 and can-... 

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