Adiabatic scanning condition

Notice that this means that the TS-PFR can be operated under isothermal or adiabatic conditions as well as any other. One way to envision this flexibility is to see isothermal reactors as operating under conditions where the heat transfer is infinite, allowing the reaction to track the control temperature perfectly. Adiabatic reactors in that view have zero heat transfer and no heat is lost from the reaction. Temperature scanning reactors operate with any value of heat transfer coefficient, including the above two extremes. 

The requirements with regard to a calorimeter can be derived on the basis of the above analysis of the measuring problem. The necessary operating conditions have to be defined first an isothermal, isoperibol, adiabatic, or a scanning calorimeter What temperature range What heating rate Any other boundary conditions a constant pressure, constant volume, gas flow rate, and so on ... 

Classical adiabatic calorimetry, in which precise quanta of heat are applied and the temperature rise of the sample is noted under shielded conditions, is an extremely slow and laborious technique. By referring the temperature of a sample to that of an inert sample experiencing a closely similar heating profile, equivalent information can be obtained in a rapid scanning experiment. This has many advantages in that structures in the polymer are not annealed and changed during fast thermal scans. 

Another development in calorimetry, at least in retrospect, was the construction of adiabatic calorimeters operating at constant heating rate. In such an instrument the heating was carried out continuously (scanning calorimeter), i.e., the measurement was not interrupted every 20 K or so to check the isothermal condition, but was carried out in one, continuous run. In such operation, the heat losses were minimized since the experiment could be completed faster, but the accuracy of such scanning calorimeters was considerably less than that of the standard adiabatic calorimeters. The reason for the lesser accuracy is the fact that the heat could not be distributed nearly as uniformly in the sample as in the adiabatic calorimeter. In addition, the loss calibration was also less accurate. 

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