INFLUENCE OF THE THERMAL-CONDUCTIVITY ON THE C-P-DETERMINATION BY DYNAMIC METHODS

Modulated DSC, Dynamic DSC and steady-state DSC are three frequently u sed methods to determine the heat capacity. This paper investigates ho w the C-p-values obtained by these methods are influenced by the diffe rent thermal conductivity of the material used for calibration and as sample. A simple mathematical model of the DSC-instrument is derived a nd the obtained C-p-values are compared for different operating condit ions of the instrument and for different samples. Experiments with dif ferent samples are also performed and compared with the simulation res ults. The results clearly show that the temperature distribution in th e sample puts a higher limit on the useful frequencies. Recommendation s for operating conditions for accurate C-p measurements are given. (C ) 1997 Elsevier Science B.V.