Basic Principles of DSC
- Differential Scanning Calorimetry (DSC) is a material thermal analysis technique that measures the heat absorption or release behavior of a sample during controlled heating or cooling.
- The core idea is to maintain the same temperature between the sample and the reference, and to reflect the thermal effects occurring in the material by comparing the energy compensation (or temperature difference) between them.
DSC is divided into two types:
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- Power-Compensation DSC
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- Two independent furnaces, with heating power regulated by a feedback system
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- High thermal response and fast speed
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- Heat-Flux DSC
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- Sample and reference placed in the same furnace, with thermal flux difference measured by a heat flux sensor
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- Simple structure, commonly found in mainstream instruments (e.g., TA, NETZSCH, Mettler)
- DSC output is heat flow, which essentially represents:
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- The rate of heat absorbed (or released) by the sample per unit time.
Common Endothermic/Exothermic Events:
- Endothermic: glass transition, melting, evaporation, desorption
- Exothermic: crystallization, curing reactions, oxidation reactions, decomposition
Key Factors Affecting DSC Measurement Accuracy
- Heating Rate
- Higher rates → sharper peaks, higher Tg
- Common: 5–20 °C/min
- Atmosphere
- Nitrogen: standard conditions
- Oxygen: for measuring OIT/OOT
- Helium: more uniform heat transfer, suitable for high-precision tests
- Sample Mass
- Typically 3–10 mg; larger samples may have uneven heat conduction.
- Sample Preparation
- Sample must be in close contact with the bottom of the aluminum crucible without gaps. Jituotech provide Differential Scanning Calorimeter testing service and analysis
