Kinetic analysis of thermogravimetric data

Abstract

Thermogravimetric data are generally more extensive than are comparable isothermal aging data, and therefore afford preliminary kinetic information in greater abundance. The kinetic analysis of the thermogram, by use of either its exact equation or a more convenient approximation formula, is straightforward in cases of volatilization via simple kinetics. Application of the analytical procedure to the thermogram for the zero-order volatilization of octamethylcyclotetrasiloxane yielded an estimate of 11.65 kcal./mole as the average heat of vaporization in the temperature range of 80 to 145°C. The apparent activation energy for the first-order pyrolytic volatilization of 200-mg. samples of pulverized polytetrafluoroethylene was estimated to be 66 to 68 kcal./mole in the temperature range of 520 to 610°C.