Differential scanning calorimetry (DSC) is a technique used to analyze thermal transitions in materials. There are two main types of DSC instruments: heat-flux DSC and power-compensated DSC. Heat-flux DSC measures the difference in heat flow into the sample and reference, while power-compensated DSC maintains the sample and reference at equal temperatures while measuring the power difference required. DSC can be used to analyze properties such as glass transitions, melting points, crystallization kinetics, and heat of reactions. It has applications in fields such as materials science, polymers, and pharmaceuticals.

1. DIFFERENTIAL
SCANNING
CALORIMETRY (DSC)

4. INSTRUMENTATION

8. 1)HEAT-FLUX DSC INSTRUMENTS
• In heat-flux DSC ,the difference in heat flow in to the sample and referenced is
measured while the sample temperature is changed at a constant rate. Both
reference and sample are heated by a single heating unit. Heat flow in to the both
sample and referece is via an electrically heated constant thermoelectric disk.
• The different heat flow in to the two pans is directly propotional to the difference in
output of the two thermocouple junction.in heat-flux DSC ,we can write the total
heat flow dH/dt=Cp dT/dt+f(T,t)
• Where H is a enthalpy in J mol-1 ,Cp is the specific heat capacity (heat capacity
per mole)in J K-1 mol-1 , and f(T,t) is the kinetic response of sample in J mol-1

10. 2)POWER-COMPENSATED DSC INTRUMENTS
• Temperature of sample and reference are kept equal to each other while both temp. are
increased and decreased linearly.
• Independent two heating unit are employed . These unit are quit small ,allowing for rapid rates
of heating and cooling,and equilibration. The sample and holders have platinum resistance
thermometer to continuously monitor the temperature of the materials.
• Both sample and reference are maintained at the programmed tepm. By aaplying the power to
the both.instruments record the power difference needed to maintained the sample and
reference at the same temp. as a function of programmed temp.
• Power-compensated dsc has lower sensitive than heat-flux dsc ,but its response time is more
rapid. This makes pcdsc well suited for kinetic studies in the fast equilibration to new
temp.setting are needed.
• This is also capable for higher resolution than heat-flux dsc..

14. ENDOTHERMIC AND EXOTHERMIC EFFECT
• When the sample absobs energy, the enthalpy change is said to be
enothermic processes such as melting ,vaporization, and
gelatinization are endothermic.
• When the sample releases energy, the prosess is said to be
exothermic. Prosesses such as crystallization and Gelation are
exothermic

19. PARAMETERS TO CONTROL
• Initial and final temperature
• Heating or cooling rate
• Amount of sample
• Thermal history of sample
• Type of gas: O2, N2, air
• Gas flow rate

27. DSC APPLICATION
• Glass transition
• Melting Point
• Crystallization time and temperature
• Heat of melting and Crystallization
• Percent Crystallinity
• Oxydative stabilities
• Compositional analysis
• Heat capacity
• Purities
• Thermal stability
• Polymorphisam

28. Thank you !!!