Thermal analytical techniques, oxidative

Riga, A. Patterson, G.H. Oxidative Behavior of Materials by Thermal Analytical Techniques, ASTM Special Technical Publication 1326, 1997, ASTM. 

The thermal decomposition characteristics of micron-sized aluminum powder and potassium perchlorate mixtures were studied with thermal analytical techniques by Pourmortazavi and coworkers [108]. The results showed that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5 pm particle size has a fusion temperature of about 647 °C, but for 18 pm powder this temperature is 660 °C. Pure potassixun perchlorate has an endothermic peak at 300 C corresponding to a rhombic-cubic transition, a fiision temperature around 590 °C and decomposes at 592 °C. DTA curves for an AI5/KCIO4 (30 70) mixture show a maximum peak temperature for thermal decomposition at 400 °C. Increasing the particle size of aluminum powder increases the ignition temperature of the mixture. The oxidation temperature is increased by increasing the aluminum content of the mixture. 

A.T. Riga, R.M. Collins and G.H. Patterson, ASTM Spec. Techn. Publ., STP 1326 (Oxidative Behavior of Materials by Thermal Analytical Techniques), A.T. Riga and G.H. Patterson (eds.), ASTM, West Conshohocken, PA (1997), pp. 91-101. 

Woo, L, Ding, S.Y. et ai. Riga, A.T., Patterson, G. H. (Hrsg) Chapter Further Studies on Oxidative Induction Test on Medical Polymers In Oxidative Behavior of Materials by Thermal Analytical Techniques, ASTM Publication, 1997... 

Different experimental approaches were applied in the past [6, 45] and in recent years [23, 46] to study the nature of the organic residue. But the results or their interpretation have been contradictory. Even at present, the application of modem analytical techniques and optimized electrochemical instruments have led to different results and all three particles given above, namely HCO, COH and CO, have been recently discussed as possible methanol intermediates [14,15,23,46,47]. We shall present here the results of recent investigations on the electrochemical oxidation of methanol by application of electrochemical thermal desorption mass spectroscopy (ECTDMS) on-line mass spectroscopy, and Fourier Transform IR-reflection-absorption spectroscopy (SNIFTIRS). 

STA has been widely used in coal studies. Combustion of coal is highly sensitive to experimental conditions and TA experiments are usually associated with low reproducibility. STA markedly enhances coal combustion reproducibility and this feature accounts for its popularity as an analytical technique for studies of the thermal behavior of coals. In simple terms, the initial drying process of a coal can easily be separated from the subsequent oxidation, which in STA can be assigned directly to a dry weight . 

The degradation of polyacrylonitrile deuteriated in the alpha position has been followed by Fourier transform i.r. spectroscopy. The results are consistent with imine-enamine tautomerism followed by oxidation to give pyridone structures. A variety of thermo-analytical techniques has been employed to study thermal and thermo-oxidative reactions and it is concluded from these that a carboxylate moiety is responsible for initiating cyclization in an oxidizing atmosphere. The role of oxygen is said to be three-fold, creation of the carboxylate initiator sites, dehydrogenation, and crosslinking. 

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