Thermal decomposition, test

Reactivity (instability) information Acceleration rate calorimetry Differential thermal analysis (DTA) Impact test Thermal stability Lead block test Explosion propagation with detonation Drop weight test Thermal decomposition test Influence test Self-acceleration temperature Card gap test (under confinement) JANAE Critical diameter Pyrophoricity... 

Drop weight test Thermal decomposition test Influence test... 

Thermal decomposition test using 5 grams of sample brought to 300 °C in 5 degree increments. 

Action of nitrous acid. To a few ml. of 20% NaNO, solution add a few drops of cold dil. acetic acid. Pour the mixture into a cold aqueous solution of glycine, and note the brisk evolution of nitrogen. NH CH COOH -h HNO2 = HO CH2COOH + N + H O. Owing to the insolubility of cystine in acetic acid use a suspension in dU. acetic acid for this test. In each case care must be taken not to confuse the evolution of nitrogen with any possible thermal decomposition of the nitrous acid cf. footnote, p, 360). 

As commercially pure materials, the ethyleneamines exhibit good temperature stabiUty, but at elevated temperatures noticeable product breakdown may result in the formation of ammonia and lower and higher mol wt species. This degradation becomes mote pronounced at higher temperature and over longer time periods. Certain contaminants, such as mineral acids, can lower the onset temperature for rapid thermal decomposition. The manufacturer should be contacted and thermal stabiUty testing conducted whenever ethyleneamines ate mixed with other materials. 

Analytical procedures sensitive to 2 ppm for styrene and 0.05 ppm or less for other items were used for examining the extracts. Even under these exaggerated exposure conditions no detectable levels of the monomers, of the polymer, or of other potential residuals were observed. The materials are truly non-food-additive by the FDA definitions. Hydrogen cyanide was included in the list of substances for analysis since it can be present at low levels in commercial acrylonitrile monomer, and it has been reported as a thermal decomposition product of acrylonitrile polymers. As shown here, it is not detectable in extracts by tests sensitive to... 

Specific Volume of Gases Formed on Explosion. 723ml/g (NG 712ml) (Ref 46) Stabilization. Chromatographically pure Mannitol Hexanitrate was mixed with varying percentages of 22 stabilizers and the mixts tested for stability in the 100° heat test best results were obtained with a mixt of 96% MHN, 2% Amm oxalate, and 2% dicyandiamide (4.07% wt loss after 48 hours, 5.74% after 96 hours) (Ref 56). The use of ethylene oxide as a stabilizer is reported in Ref 27 Thermal Decomposition. Slow heating causes decompn at 150° with evolution of red fumes (Ref 20, p 249)... 

Young s moduli were determined in tensile tests using samples of 4 mm thickness. Slow cyclic loading (frequency 0.01 Hz) with small strain amplitudes (s < 3%) was used for the tests in order to maintain the thermal equilibrium as much as possible. The temperature range was limited to 260 °C as thermal decomposition became noticeable above this temperature [11],... 

Diacyl peroxides undergo thermal and photochemical decomposition to give radical intermediates (for a recent review, see Hiatt, 1971). Mechanistically the reactions are well understood as a result of the many investigations of products and kinetics of thermal decomposition (reviewed by DeTar, 1967 Cubbon, 1970). Not surprisingly, therefore, one of the earliest reports of CIDNP concerned the thermal decomposition of benzoyl peroxide (Bargon et al., 1967 Bargon and Fischer, 1967) and peroxide decompositions have been used more widely than any other class of reaction in testing theories of the phenomenon. 

The effectiveness of incineration has most commonly been estimated from the heating value of the fuel, a parameter that has little to do with the rate or mechanism of destraction. Alternative ways to assess the effectiveness of incineration destraction of various constituents of a hazardous waste stream have been proposed, such as assessment methods based on the kinetics of thermal decomposition of the constituents or on the susceptibility of individual constituents to free-radical attack. Laboratory studies of waste incineration have demonstrated that no single ranking procedure is appropriate for all incinerator conditions. For example, acceptably low levels of some test compounds, such as methylene chloride, have proved difficult to achieve because these compounds are formed in the flame from other chemical species. 

The crucial test of all of the theories based on solvation would be the absence of the isokinetic relationship in the gas phase, but the experimental evidence is ambiguous. Rudakov found no relationship for atomization of simple molecules (6), whereas Riietschi claimed it for thermal decomposition of alky] chlorides (96) and Denisov for several radical reactions (107) however, the first series may be too inhomogeneous and the latter ones should be tested with use of better statistics. A comparison of the same reaction series in the gas phase on the one hand and in solution on the other hand would be most desirable, but such data seem not to be available. 

Recent work on [CpFe(CO)2]2 was intended to test whether once again a complex molecule could be found to have a high yield and also to test a possible preferential formation of metal carbonyls over metal sandwich compounds. In this compound, thermal decomposition of the starting compound gives rise predominantly to ferrocene (28, 68). The data (50) given in Table VIII show that indeed the carbonyl is preferentially formed... 

The low thermal stability of many poly(iminocarbonates) limits the use of melt fabrication techniques such as injection molding or extrusion. For example, among all six polymers tested, only poly-(Dat-Tyr-Hex) and poly(CTTH) had low enough softening points to be compression moldable without a significant degree of thermal decomposition. ... 

Most chemical substance manufacturers systematically submit their new substances (or preparations) to tests that enable them to evaluate the decomposition risks. There are many types of apparatus that are used to test the effect of the different physical causes of instability. The most important are the mechanical and thermal sensitivity tests. The methods listed below are simply intended to give an idea of the available experimentel possibilities. 

Producing Thermal Decomposition Products from Materials in an Air Stream and Their Toxicological Testing Part 1. Test Method 53436. Deutsches Institut fur Normung, Berlin, 1981. 

Cronin, J. L., and P. F. Nolan, "The Comparative Sensitivity of Test Methods for Determining Initial Exotherm Temperatures in Thermal Decompositions of Single Substances," J. Haz. Mat., 14 (1987). 

Apart from tests carried out on single crystals, also fractions of uniform particle size should be tested in order to obtain precise readings and to ensure reproducibility of results. For runs in vacuo the use of particle sizes under 60 (0.25 mm) mesh should be avoided, since the gaseous products in the case of thermal decomposition may eject particles of the test material from the crucible. 

Thermal stability tests were carried out in inert and reducing atmospheres such as N2 and CO. In both cases the decomposition started at lower temperatures, at about 950 and 800 °C respectively, with formation of red-brown colored reaction products due to the presence of Cu20. 

Schofield, F. Use of a range of tests to determine detonation capability, localised thermal decomposition, thermal stability of reaction masses and effects of prolonged storage translation of these results to industrial-scale processing operations. 

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