Theoretical Fundamentals of Differential Scanning Calorimeters

Abstract

In all DSCs, a temperature difference ΔT — given as a voltage — is the original measurement signal. In almost all instruments a heat flow rate Φ _m (differential heat flow rate) is internally assigned to ΔT. Independent of whether the user obtains ΔT or Φ _m from the respective DSC, knowledge of the functional relation between the measured signal (ΔT, Φ _m ) and the quantity searched (the reaction heat flow rate Φr consumed/produced by the sample) is important for:

• the time-related assignment of _Φrto ΔT or _Φm(investigation into the kinetics of a reaction),

• the determination of partial heats of reaction,

• the evaluation and assessment of the influences of operating parameters and properties of the measuring system with regard to this relation,

• the estimate of the overall uncertainty of measurement.