Simultaneous thermogravimetric and thermo-gastitrimetric investigations under quasi-isothermal and quasi-isobaric conditions

The derivatograph has been modified to provide a new technique with the help of which the weight change of a sample and the amount of the evolving gases can be determined as a function of the temperature of the sample under quasi-isothermal and quasi-isobaric conditions. The thermal decompositions of potassium and sodium hydrogencarbonate were investigated; it was established that under special conditions the otherwise one-step thermal decomposition of the two materials becomes a two-step process. The phenomenon involves a change only from the point of view of kinetics, for the decomposition itself does not split into two consecutive processes.