Differential Scanning Calorimetry (DSC) is a thermal technique used to measure the energy changes as the test materials response to changes in temperature. This analytical tool is useful in studying the melting of a crystalline polymer, determining the glass transition (Tg) of coatings and quantifying coating curing reactions. The Tg is one of the most vital characteristics of a coating, this property can be related to cross-link density and can be used to predict use temperature. For a coating to acquire reasonable mechanical properties the Tg must be above the use temperature. If the Tg is below the use temperature the coating will be soft and often tacky.
DSC technique is broadly used for measuring the thermal characteristic of polymeric coatings, especially Fusion Bonded Epoxy (FBE) coating. During the thermal scans, a plot of endotherm/exotherm as a function of temperature is acquired and recorded at a set rate of temperature increase. By analyzing the plots, the information about the coating’s glass transition and degree of cure can be obtained.
Test methods for the impact resistance are available in:
- ASTM E1356
- ASTM D3418
- CSA Z245.20, Section 12.7
- NACE SP0394, Appendix D
- API RP 5L7, Appendix 5
- ISO 11357-2
Test Samples:
- FBE powder
- Liquid paint sample
- Applied coating sample