When can the effect of thermal inertia be considered negligible?

Abstract

This paper is a response to Sestak's comments entitled "The evaluation of nonisothermal thermoanalytical kinetics is simplified without the description of heat transfers, such as thermal inertia, which is not negligible, as indicated by Vyazovkin." It is stressed that Vyazovkin has never claimed that thermal inertia is generally negligible. Rather, he discussed the conditions, under which its effect on the activation energy can be diminished to the level when it can be neglected. Such conditions are accomplished by diminishing the sample mass and heating rate. The effect of thermal inertia is likely to be brought down to a negligible level by keeping the product of the sample mass and heating rate below 100 mg K min −1 or, better yet, the product of the time constant and heating rate below 2-3 K. The final judgement is to be based on statistical analysis that compares the activation energies derived respectively from the data uncorrected and corrected for thermal inertia. As long as statistical analysis suggests that the difference in the activation energies is statistically insignificant, one can consider the effect of thermal inertia negligible.

Dynamic Character of Thermal Analysis Where Thermal Inertia Is a Real and Not Negligible Effect Influencing the Evaluation of Non-Isothermal Kinetics: A Review

“…Still others use philosophical resignation, saying that science is never accurate, and it only approximates the truth-as an excuse for knowingly using inaccurate and simplified thermodynamic models while the ways to correct them has been known for a long time [11][12][13]. If Newton, Fourier, Carnot and Tian were proponents of simplified continuity and motivated by today's job security, i.e., the need to maintain easier approaches, they would not bother to examine the impractical complexities and ineffectual intricacies of heat transfer, which form an inseparable basis for thermal analysis [14][15][16][17].…”

“…Although thermal analysis has thermal in its name, its practical application factually circumvents incorporation of thermal transfer relations. It manifests itself in the endless discussion of whether or not thermal inertia has an effect on the specific evaluation of thermo-analytical kinetics, which seems unceasing [11][12][13][14]. In [14], it was said that the effects of heat transfer in general are diminished by using smaller sample masses (m) and slower heating rates (β).…”

“…It manifests itself in the endless discussion of whether or not thermal inertia has an effect on the specific evaluation of thermo-analytical kinetics, which seems unceasing [11][12][13][14]. In [14], it was said that the effects of heat transfer in general are diminished by using smaller sample masses (m) and slower heating rates (β). It is clear that more equilibrated conditions keep reducing the effect of thermal inertia approaching stationarity.…”

“…It is clear that more equilibrated conditions keep reducing the effect of thermal inertia approaching stationarity. It also follows in [14] that the result of the ICTA kinetic committee work [15] says nothing more that is logically obvious, i.e., that the kinetics are less affected by heat transfer the closer they are to the equipoise (isothermal) regime, e.g., introduced by decelerate heating. The remark in [13] also points to the negligibility of thermal inertia due to the decreasing sample size that was previously exposed on the samples of large and small cars in collision.…”

“…Figure 1 left. need to maintain easier approaches, they would not bother to examine the imprac complexities and ineffectual intricacies of heat transfer, which form an inseparable b for thermal analysis [14][15][16][17].…”