AKTS AG
TechnoArk 3
3960 Siders
Switzerland


Customer service:
Phone:+41-848-800221
Fax:+41-848-800222
 

Experiments

Isothermal or non-isothermal experiments ?

Isothermal data

Thermoanalytical scans under isothermal conditions are usually carried out in a narrow temperature range due to technical problems (particularly too fast/at high temperature or too slow/at low temperature reaction times). Therefore, the obtained data may not contain the necessary depth of information for full identification of the complexity of a process.

Under isothermal conditions, we may be faced with apparent kinetic findings involving one reaction only whereas under non-isothermal conditions we have to consider several reactions. This is due to the isothermal scans being usually collected over a narrow range of temperatures (e.g. deltaT = 30 °C) as compared to the non-isothermal data. In such narrow temperature ranges, the isothermal reaction progress may be well described by using a single kinetic model not expressing the complexity of the reaction process. Non-isothermal data usually cover a wide range of temperatures (e.g. deltaT = 300 °C).


Non-isothermal data

In general, non-isothermal scans with different heating rates allow the coverage of a much wider range of temperatures than is possible for isothermal conditions. This allows discernment between the different reaction paths involved in the kinetic process because the data contain the necessary depth of information.

AKTS-TA computations are usually made for 6 heating rates e.g. 1, 2.5, 5, 10, 15, 20 K/min. The application of heating rates too close to each other should be avoided, since they overly narrow the temperature range of non-isothermal scans. If they are very close, they become tantamount to a model-fitting analysis using single heating-rate methods. Consequently, they may not discern the kinetic characteristics and therefore fail the required purpose.

For more information about this important topic click here.