Search Results

You are looking at 81 - 90 of 3,317 items for :

  • "thermal analysis" x
  • All content x
Clear All

The present state of the certification of the reference materials for thermal analysis is considered. Six sets of reference materials for temperature calibration, resulting from the research work of the ICTA Standardization Committee, are discussed.

Restricted access

Abstract  

A thermal analysis method that separately reproduces the gas and condensed phase processes of flaming combustion in a single laboratory test is described. Anaerobic pyrolysis of solid plastics at a constant heating rate and complete thermal oxidation (nonflaming combustion) of the evolved gases provides the rate, amount, and temperatures over which heat is released by a burning solid. A physical basis for the method, the test procedure, and the relationship of flammability parameters to fire response and flame resistance of plastics are described.

Restricted access

This review paper outlines some current developments in thermal analysis. The current status of standard methods, in particular those issued by the American Society for Testing and Materials (ASTM), using thermal analysis techniques are discussed. In the second place a simple method for the determination of the oxidative stability of polyethylene by DTA is reviewed. Finally the paper surveys some of the more recent work being carried out in fossil fuels and fuel oils.

Restricted access

method is based on the following equation [ 8 ]: 6 Objective The objective of the present study is to investigate the kinetic parameters of thermal degradation through thermal analysis behavior of three

Restricted access

complexes of the bismuth in the aqueous solution. We have found that some solid complexes of bismuth can be prepared easily through solid–solid reaction [ 27 , 28 ]. Thermal analysis is important to study the chemical structure and the reaction course of

Restricted access

Abstract  

A new complex, diaquadi(1,2,4-triazol-5-one)zinc(II) ion nitrate formulated as {[Zn(TO)2(H2O)2](NO3)2}n (1) (1,2,4-triazole-5-one, abbreviated as: TO) was synthesized and characterized by elemental analysis, X-ray single crystal diffraction, infrared spectrum (IR), differential scanning calorimetry (DSC), thermogravimetric analysis and differential thermogravimetric analysis (TG-DTG). The X-ray structure analysis reveals that the complex is orthorhombic with space group Pbca and unit-cell parameters a=6.9504(2) �; b=10.6473(3) �; c=17.8555(5) �. Based on the result of thermal analysis, the thermal decomposition process of the compound was derived. From measurement of the enthalpy of solution in water in 298.15 K, the standard molar enthalpy of solution of lignand TO and the complex were determined as 15.43�0.18 and 52.64�0.42 kJ mol−1, respectively. In addition, the standard molar enthalpy of formation of TO(aq) was calculated as −126.97�0.72 kJ mol−1.

Restricted access

Controlled-rate thermal analysis

Study of the process of super hard material debinding

Journal of Thermal Analysis and Calorimetry
Authors: Tadashi Arii, Kiyoshi Terayama, and Nobuyuki Fujii

Binder burnout has been carried out by a controlled heating programme which depends on the composition of the binder system used. The present paper gives the principle of constant decomposition rate thermogravimetry, which falls within controlled-rate thermal analysis, and the advantage of this technique when evolved gas analysis is used in discriminating the process of super hard material burnout by comparison with the conventional linear heating method is described. In this technique, the sample temperature is varied to maintain a constant rate of mass loss by control of the heating of the infrared image furnace. Since the constant decomposition rate control (CDRC) allows a much better control of the sample environment, which generally depends on the rate of gas evolution, it is possible for uniform conditions to exist throughout the sample, and the total burnout time can be reduced considerably without crack formation. The efficiency of this CDRC was proved by the obtained temperaturevs. time curve and SEM observations of the heat-treated sample after the debinding process.

Restricted access

Controlled-rate thermal analysis

Characterization of heterogeneity of active carbon surfaces and adsorbed water layers

Journal of Thermal Analysis and Calorimetry
Author: P. Staszczuk

Controlled-rate thermal analysis (CRTA) and differential scanning calorimetry (DSC) were used to investigate the adsorbed water layers and the surface properties of different commercial activated carbons. A simple method is proposed to obtain information on the properties of the adsorbed water film and the surface heterogeneity of the materials studied. This method utilizes TG mass loss and the first derivative of the DTG mass loss curves with respect to temperature and time, obtained during programmed liquid thermodesorption. The obtained TG mass loss curves, which reflect the energetic heterogeneity, consisted of steps and inflections which were associated with the mechanism of wetting of the solid surfaces. The heights of these steps and inflections depend on the adsorption capacity, the adsorption potential and the nature and number of the active centers of the carbon samples studied. The values of the total porosity and the surface phase capacity obtained by this method are in good agreement with those estimated on the basis of independent methods. The behaviour of water/carbon samples was studied by means of DSC at subambient and elevated temperatures. The experimental results provided novel data on the structural heterogeneity, the thermal stability of the water/carbon interface and its phase and structural transitions.

Restricted access

tasks. Commercially available thermal analysis devises are not designed to study reaction kinetics. So in the general case, one cannot clearly identify the heat exchange conditions between the environment and the experimental cell based on its design

Restricted access

Abstract  

Two types of thermal effects, caused by substitutions (Ca2+↔ Na+, ↔ CO3 2-, SO4 2-, OH-↔ F-) in synthetic precipitated apatites as well as by sorption of Cd2+, Zn2+, and Cr3+ ions from the solutions were studied by TG/DTA, XRD and FTIR analysis. The temperatures of exothermic effect at 330-340°C and of decomposition of carbonate and sulfate apatites at 650-950°C were shown to depend on the substitutions in the apatite structure.

Restricted access