Violet Test

Stability. Heat stabihty is determined by measuring the time required for a specific amount of CN, held at 134.5°C, to decompose and discolor methyl violet test paper (75). 

Note The Observation Test was intended to detect the initial decompn of propint, and was conducted at ail depots and posts where powder was stored. A 6oz sample of each lot of powder with a strip of methyl violet test paper was placed in a glass-stoppered bottle, with the paper not in contact with the powder. The test was conducted in the magazine in which the proplnt under test was stored. Bleaching of the test paper was taken as an indication that the powder had started to de-... 

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)... 

Loss of Weight Test, Marqueyrol s Test, Meerscheidt-Hullessem Test, Mittasch s Test, Obermiiller s Test, Pavlik s Test, Methyl Violet Test, Silvered Vessel Test, Simon Thomas Test, Spica Test, Sy Test, Taliani Test, Taylor s Test, Tomanari s Test, Vacuum Stability Test, Vieille Test, Warmlagermethode 75° (German Storage Test), Will Test... 

It was adopted by the US Ordnance Dept (Ref 2), but the temperatures of the test were 120° for double-base propellants and 134.5° for single-base propellants for NC s (Ref 3). Litmus paper was originally used in this test (Refs 1 8c 2) but later this was changed id methyl violet paper and the test was called the Methyl Violet Test Apparatus ... 

Normal methyl violet test paper is prepd by soaking filter paper in a normal solution of rosaniline acetate-crystal violet and drying... 

The stability test for nitrocellulose powder at a temperature of 134.5°C the sample will not be considered serviceable unless the time necessary to produce the evolution of nitrogen oxides is at least 45 min and the powder withstands this temperature without exploding for 5 hr. The test can be combined with methyl violet test decoloration of the test paper should not occur before 30 min or longer according to particular specifications. 

The test for nitroglycerine powders at a temperature of 120°C (nitroglycerine powders cannot withstand higher temperatures) here the same conditions apply as in the test for nitrocellulose powders, viz. appearance of the nitrogen oxides after a lapse of at least 45 min and no explosion for 5 hr. The same test can be carried out in the presence of methyl violet test papers. Decoloration of the paper should not occur before 30 min. 

Tonegutti and Debenedetti [63] found that this test also agrees well with the methyl violet test at 120°C. 

VIOLET TEST OF ITALIAN DOUBLE BASE POWDER (POLVERE C)... 

Sample Date of manufacture NaN02 in mg % Decoloration of methyl violet test paper at 120°C after min... 

Heat test at 134.5°C. This heat test is in use in the U.S.A. A sample of 2.5 g of nitrocellulose or nitrocellulose powder ( single base powder ) is kept in a long test tube in a constant temperature bath regulated to 134.5+0.5°C. A band of methyl violet (rosaniline acetate with crystal violet) test paper is kept over the surface of the sample. The test paper should not change to salmon colour before 30 min and no visible N02 vapours should be detected before 45 min. 

Test Papers. See under Methyl Violet Tests in Vol 8, M118-Lto M120-L, and Lead Acetate in Vol 1, A28-R... 

Procedure Transfer about 300 mg of the test article (accurately weighed) to a 150-mL beaker, dissolve in 1.5 mL of anhydrous formic acid, and add 60 mL of glacial acetic acid. Add crystal violet Test Solution, and immediately titrate with 0.1 N HCIO4 to a green endpoint. Perform a blank determination, and make any necessary correction. Each milliliter of 0.1 N HCIO4 is equivalent to 29.43 mg of aspartame. The method description cautions that a blank titration exceeding 0.1 mL may be due to excessive water content, and may cause loss of visual endpoint sensitivity. 

Methods in which the escaping nitrous gases can be recognized visually or by noting the color change of a strip of dyed filter paper. The former methods include the qualitative tests at 132, 100, 75, and 65.5 °C (270, 212, 167, and 150 °F). These tests include the U.S. supervision test, the methyl violet test, the Abel test, and the Vieille test. 

Colour Tests. Mandelin s Test—violet Test—violet. 

Methyl violet test for stability of explosives, 79 Mineral jelly, for use in explosives, examination of, 14 in nitroglycerine, 5a... 

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