Differential Scanning Calorimetry

During phase and state transitions or chemical reactions during heating and cooling of materials, we can determine changes in their specific heat capacity and enthalpy. These are recorded in a DSC analysis by measuring the heat flow, in other words the amount of heat absorbed or released by a material sample.

In this way, polymers can be characterised and, for example, reaction and transition temperatures can be determined or cross-linking reactions can be detected.

DSC analysis is suitable for both elastomers and thermoplastic materials and can be applied very well to finished parts.

Significance for Application Technology

In the elastomer sector, we often use DSC analysis to determine the glass transition temperature. In addition, it offers the possibility of detecting residual amounts of curing agent in the elastomer.

The DSC Test

The standards ISO 11357-2, ASTM D 3418, ASTM D 7426 and VDA 675116 describe test methods for thermal analysis with DSC.

The principle of the DSC method is based on the heat flow between a material sample and a reference. For the measurement, you place a material sample in an encapsulated container, a crucible. This sample crucible undergoes a defined, linear temperature programme at the same time as the reference crucible, which is usually empty.

The measured sample temperature and the temperature difference between the sample crucible and the reference crucible are used to determine the heat flow. Changes in the heat capacity of the sample due to phase transition or chemical reaction during the course of the temperature programme cause a change in the heat flow.

The result of the measurement is a thermogram, which shows the endothermic and exothermic processes of the material sample.