DSC Flashcards
What is DSC
Thermal analysis technique in which the heat flow into or out of a sample is measured as a function of temperature or time, while sample is exposed to a controlled temperature program
What can be measured using DSC
Glass transition temperature melting point , crystallization, specific heat capacity , cure process , purity, oxidation behavior and thermal stability
Why DSC is important
Used to measure enthalpy changes due to changes in physical and chemical properties of a material as a function of temperature or time
- Test data for a wide range materials
Types of DSC
Power differential DSC
Heat-flux DSC
Power differential DSC
Measures the difference in power supplied to the sample and reference
Heat-flux DSC
Measure the difference in heat flux between the sample and reference
Heat flow & Enthalpy measurement
Detect the differential variation in heat flow (y-axis in mW) against that of time / temperature (x-axis in second,minutes or degree celsius
Why heat flux is down for endothermal
The heat is absorbed by the sample during enthalpy change
Heat capacity
Amount of energy a unit of matter can hold
. Heat capacity for molten material is higher than that of a solid
Crystallinity Point (Tc)
When a polymer reaches its crystallization point, molecules align in neat chains or stacks of chains. This intermolecular bonding makes the polymer much stronger
Determination of Crystallinity
@= ^h/^hc . 100
^h=specific enthalpy
^hc= enthalpy of fusion of 100% crystalline material
