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Thermophysical properties characterization of a resin during curing using differential scanning calorimetry and the flash method
J. Blumm, A. Lindemann and S. Schmoelzer
For decades, the flash method [1] has been well-known for characterizing the thermophysical properties of solid materials. Fast measurement times, easy sample preparation, and high accuracy are only some of the advantages of this non-contact, non-destructive measurement technique. Nowadays, characterization of resins is becoming increasingly important for industrial applications. Generally, differential scanning calorimetry (DSC) or dielectric analysis (DEA) are employed to get some information about the curing process. The thermal diffusivity and thermal conductivity are parameters which can be used to follow the cross-linking reaction in a sensitive way, as well. However, the use of the flash technique is not easy for this kind of application. The sample undergoes a transition from a generally high-viscous liquid to a solid during cross-linking which is generally related with some shrinkage. To measure samples like this, an appropriate sample holder is required which can take up the liquid sample and which is not deformed or damaged during the cross-linking reaction. Furthermore, it has to keep the sample in a disk-shaped form.
Presented in this work are technical details of a special LFA container system, allowing measurements to be carried out on resins during a cross-linking reaction. Furthermore, measurement results on a two component epoxy resin, carried out with a flash device and the new container, are shown. The flash results are correlated with measurements of the apparent specific heat carried out by differential scanning calorime try and thermokinetic analysis. This allows to get a more detailed insight into the cross-linking/curing process.
Keywords: Resin, specific heat, thermophysical properties, thermal conductivity, thermal diffusivity, laser flash, differential scanning calorimetry.