Flynn-Wall method

Similar to studies reported by Litwinienko and co-workers discussed above, a recent report (Dunn, 2006b) demonstrated that non-isothermal (conventional) DSC, static mode P-DSC and dynamic mode P-DSC may be employed to study kinetics of the oxidation of SME. OT results obtained at ambient pressure for DSC and P = 2000kPa for P-DSC and with varying p = 1-20 °C/ min were analyzed by the Ozawa-Flynn-Wall method to calculate activation energies and rate constants. This work concluded that rates of the oxidation reaction could be calculated at any temperature based on accurate measurement of kinetic parameters from analysis of non-isothermal dynamic mode P-DSC scans. 

C. Popescu (1996). Integral method to analyze the kinetics of heterogeneous reactions under non-isothermal conditions A variant on the Ozawa-Flynn-Wall method. Thermochimica Acta 285 (2) 309-323. 

Determination of Apparent Activation Energy by Ozawa Method (Ozawa-Flynn-Wall Method) [9]... 

The calculation of the activation energy is based on multiple scan methods where several measurements at different heating rates are needed, i.e. the iso-conversion methods the Ozawa-Flynn-Wall method, the Kissinger-Akahira-Sunose method and the expanded Friedman method. The first two are described in Section 3.3.1. The expanded Friedman method is expressed in the form... 

Usually the TG curve should be determined at a slow heating rate, and E was estimated for low conversion (say mass loss 5%) by using the Ozawa-Flynn-Wall method. If we assume t( = 20 000h, Tf equals the thermal index of the material. With the use of higher temperatures, the shorter is the lifetime, as shown in Figure 5.1. 

The decomposition kinetic analysis of the mass loss curves was carried out using standard TGA kinetics software that is based on the Flynn-Wall method (Flynn and Wall 1966a,b) and described in Section 3.5.5. In this technique a plot of the logarithm of the heating rate (log q) against the reciprocal of the absolute temperature [see. Eq. (3.23)] was made where the conversion or mass loss equaled 4%, 5.5%, 8%, 12%, 18% and 26%. From the slope of this plot (Fig. 3.32) the activation energy for decomposition E) was calculated from Eq. (3.32), which is based on Eq. (3.23) ... 

In this section we briefly review commercial thermogravimetric analyzers in alphabetical order of manufacturer. Please visit the respective supplier Websites for current offerings and more information. See Section 3.2.1 for descriptions of balance configurations. While most suppliers offer autostep-wise software to control the furnace temperature (see Fig. 3.40), kinetics software such as the ASTM El 641 Flynn-Wall method described in Section 3.5.5, and the ability to interface to a Fourier transform infrared spectrometer (FTIR) or mass spectrometer (MS), the reader interested in these applications is advised to confirm the features of particular TGA systems. 

Conversion, a Ozawa-Flynn-Wall Method Friedman s Method ... 

Kinetic model of Ozawa—Flynn—Wall method... 

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