Authors:O. P. Mchedlov-Petrossyan, V. L. Chernyavski, and V. Y. Dubnitski
The paper describes the results of statistical analysis of DTA diagrams. A connection is found between the second and third endothermal effects. An analysis of geometrical characteristics of theT, S andh values of DTA diagrams confirms the absence of reliable connections. The rank correlation coefficients are determined according to Spearman. Non-linear programming is formulated to obtain the kinetic dependencies of the process of hydration of cement studied by DTA.
Attempts were made to apply DTA together with TG for the investigation of asphalt-poly(methyl methacrylate) systems. Compositions were made by photopolymerization of methyl methacrylate in the presence of asphalt or asphalt components.
Thermogravimetric analysis in conjunction with evolved gas analysis are discussed for powder PMMA, particle diameter of 0.1
mm. Furthermore, differential thermal analysis measurements were performed in both pure nitrogen and oxidative environment.
These measurements are conducted to assess major differences associated with particle size. The results indicated for powder
PMMA, in pure nitrogen the degradation can be described as three-step reactions, while in oxidative environment it is two-step
reactions. Furthermore the reaction in both environments are mainly endothermic. This in contrast to results reported for
industrial-grade PMMA with relatively larger particle size of 0.5 mm.
Authors:V Vinciguerra1, R Bucci, F Marini, and A Napoli
The thermal decomposition
of iminodiacetic, oxydiacetic, and thiodiacetic acids in helium atmosphere
has been studied by means of thermogravimetry (TG), differential thermal analysis
(DTA) and temperature-programmed pyrolysis directly coupled with mass spectrometry
(TPPy-MS). Evolved gas analysis (EGA) profiles of iminodiacetic and oxydiacetic
acids were obtained and compared with TG and DTA profiles.
of iminodiacetic acid forms water, CO, CO2, CH3CN,
HCN and some hydrocarbons. After water evolution a cyclic anhydride is formed,
as well as for oxydiacetic acid. Thiodiacetic acid vaporizes without decomposition.
Theβ →γ transformation of Ca2SiO4 was investigated with regard to the disintegration of the sinter in alumina manufacturing. DTA was applied to study the effect of the reducing atmosphere upon the course of the polymorphic transitions of Ca2SiO4, and particularly the self-disintegration process. Pure synthetic dicalcium orthosilicate and blends of pure components from the system CaO-Al2O3-SiO2-Fe2O3 were compared with technological mixtures of limestone and fly ash. Data obtained from the DTA runs allowed the specification of technical parameter for both firing and cooling of the sinter.