Bergmann and Junk test

For nitrocellulose, including guncotton, the most suitable stability test is the B and J (Bergmann and Junk) test in which 2 g dried material is heated for 2 h at 132°C, the gases evolved being dissolved in water. The nitric acid in this water is reduced to nitric oxide, which is measured by volume. 

Bergmann and Junk test. The Bergmann and Junk [92] test consists in determining the quantity of N0+N02 lost by the sample (2 g of nitrocellulose or 5 g of nitrocellulose powder) when heated at 132°C for 2 hr. The test tube is closed at one end with a hydraulic seal (Fig. 4). The latter may be ball shaped (a) or (more frequently) bell shaped (b). After the test, the tube is withdrawn from the thermostat and cooled to the room temperature. Water is sucked into the tube, which is then... 

Fig. 4. Tubes for Bergmann and Junk test (a) with balls, and (b) with tubular ending, (c) thermostat with tubes.

Stability Tests. The tests are described in Section C (p. 70 et seq. The Heat test, Bergmann and Junk test, and Will test are frequently applied. A limit of 10 mins, at 170 F. is laid down by the Home Office for the Heat test. 

V. Quantitative Determination of Nitric Peroxide Bergmann and Junk Test... 

Bergmann and Junk Test (Zeits. Angew. Chem., 1904, 982). 

Bergmann and Junk test Manomclric lest Literature... 

Quantitative tests are rarely conducted in magazines and for production inspection purposes except for a test devised by Bergmann and Junk [62] in which the quantity of acid products (calculated as NO) evolved by the powder is determined by titration. The quantity of NO evolved on heating for 2 hr at a temperature of 132°C should not exceed 2.5 cm3 NO per 1 g of powder. (For more details see Vol. II p. 26.) Other quantitative tests are usually employed in research. 

A method, developed by Bergmann and Junk in 1904, for testing the chemical stability of nitrocellulose it was also subsequently employed for testing single-base powders. The test tube, which contains the specimen being tested, and which is equipped with a cup attachment, is heated at 132 °C= 270.4°F for two hours (nitrocellulose) or five hours (single base powders). At the end of the heating period the sample is extracted with water, and the test tube filled to the 50-ml mark with the water in the cup. The solution is filtered, and the content of nitrous oxides is determined by the Schulze-Tiemann method on an aliquot of the filtrate. 

Obermuller ( Jour. Soc. Chem. Ind., April 15, 1905) considers Bergmann and Junk s test is too complicated and occupies too much time he proposes to heat gun-cotton to 140° C. in vacuo, and to measure continuously by means of a mercury manometer the pressure exerted by the evolved gases, the latter being maintained at constant volume the rate at which the pressure increases is a measure of the rate of decomposition of the nitro- cellulose. 

Benzene, mono-nitro- and di-nitro-benzene, 134. Bergmann and Junk on nitro-cellulose tests, 268. Bemthsen summary of nitro-benzenes, 133. Blasting gelatine, 119. 

Mayrhofer Stability Test. A modification of the Bergmann-Junk Test (see Vol 2, B102-R) for testing the stability of NC and propellants. Mayrhofer recommended the use of 20ml of a 2% Kl soln instead of w for the quant collection of decompn products. He also tested NG contg propints in both dry and si moist states, and found that while a stable sample behaved in a similar manner whether heated dry or moist, an unstable powd decompd rapidly in the presence of traces of w. Tonegutti (Ref 3) considered this test reliable for ballistites and unreliable for cordites... 

Davis, Vol 2 (1943) Sensitivity of NG (p 209) Stability Tests for NC, which include Kl-Starch Test at 65.5°, Methyl Violet Test at 134.5°C, Bergmann-Junk and Vacuum Tests (267-69) Testing of Detonators by Nail Test and by US Bureau of Mines Sand Test (421-24)... 

CDj) T. Urbanski, Vol 2(1965), pp 22-31 gives methods for determining the Stability of Nitric Esters, which include Abel Heat Test, Litmus Test (Vieille Test), Heat Test at 134.5°C, Silvered Vessel Test, Loss of Weight Test, Will Test, Bergmann Junk Test and Manometric Test... 

The acids attack KI and the liberated iodine colors the starch paper c)Koehler Mar-querol(Ref 2) do not recommend the use of Abel s test for NC propellants contg Ca carbonate - Bergmann-Junk test(qv) gives more reliable results... 

NAC with N ca 11.5% has been used in Italy as an ingredient of DEGDN propellants (polveri al nitroglicol). Following are Ital military specification requirements (Ref 7) nitrogen content 11.20-11.70%, fineness <90, acetyl content > 1.50,% ash < 1%, lime calcd as CaO 5L 0.30%, stability by 80° Abel test > 25 by 135° Ger test 50 min and by 131° Bergmann-Junk test < 1.75 cc of NO... 

Nitration of amylose was carried out according to the Will Lenze method, using mixed nitric-sulfuric acid as described under nitration of starch(Ref 4). The resulting product had N=12.96%, soly in ale 20% and stability(by Abel and Bergmann-Junk tests) higher than for aminopectin nitrate(Ref 5). 

Bergmann Junk Test(B-J Test). The original test, designed by Bergmann Junk(Ref 1) for testing stability of NC and propellants, was modified during WWI by Mayrhofer(Ref 2) and later by Meerscheid-Hullessem(Ref 4). The test has been widely used in Europe and to some extent in the US... 

Thermal Stability by 82.2° K1 Test Bergmann-Junk Test, ca the same as NG and Velocity of Detonation, 7270 m/sec. This compd and related a-mono a,a disubstituted glycerol nitrates have been claimed to be useful expl components... 

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