Differential Thermal analysis and Differential Scanning calorimetry.

In this slides contains Differential Thermal analysis (DTA) and Differential Scanning calorimetry (DSC).
Presented by : J.Vinay Krishna (Department of industrial pharmacy).
RIPER, anantapur.

1.   A Seminar as a part of curricular requirement for Master of Pharmacy, I Year - I semester Presented by J. Vinay Krishna (20L81S0806) Dept of. Industrial Pharmacy Differential Thermal Analysis (DTA) & Differential Scanning Calorimetry (DSC) Under the guidance/Mentorship of Dr. Hindustan Abdul Ahad M. Pharm., PhD., FAGE Professor & Head, Department of Industrial Pharmacy, Program in charge (PG)

2. The Information Provided in this PPT For Education Purpose Only 2

3. Differential Thermal Analysis (DTA) The temperature difference between a sample and an inert reference material, DT = TS - TR, is measured as both are subjected to identical heat treatments. 3

4. 4 Differential Scanning Calorimetry (DSC) The sample and reference are maintained at the same temperature, even during a thermal event (in the sample) The energy required to maintain zero temperature differential between the sample and the reference, dDq / dt , is measured

5. Sample and Reference Placed in Heater Constant Heating Rate Initial Temp Final Temp Heating Rate (°C/min) Data Temp of Sample vs Time (or Temp) Temp of Reference vs Time (or Temp) Reference should be inert 5 DTA

6. Measures Heat of crystallization Glass Transition Temperature 6

7. Differential Thermal Analysis DTA involves heating or cooling a test sample and an inert reference under identical conditions, while recording any temperature difference between the sample and reference. This differential temperature is then plotted against time, or against temperature. Changes in the sample which lead to the absorption or evolution of heat can be detected relative to the inert reference. 7

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9. Instrumentation Sample holder Sample and reference cells (Al) Sensors Platinum/Rhodium or chromel / alumel thermocouples one for the sample and one for the reference joined to differential temperature controller. Furnace Alumina block containing sample and reference cells Temperature controller Controls for temperature program and furnace atmosphere 9

10. Differential Thermal Analysis Advantages: Instruments can be used at very high temperatures. Instruments are highly sensitive. Flexibility in crucible volume/form. Characteristic transition or reaction temperatures can be accurately determined . 10 Disadvantages: Uncertainty of heat of fusion, transition, reaction estimations is 20 - 50%.

11. Differential Scanning Calorimetry DSC is a thermal analysis method where differences in heat flow into a substance and a reference are measured as a function of sample temperature, while both are subjected to a controlled temperature program. 11

12. The basic difference between DTA and DSC DSC- calorimetric method, energy differences measured. DTA- temperature differences measured. The applications of both techniques are similar, but DSC is now more popular. DTA is used for higher temperature and qualitative applications. DSC is used for calorimetric determinations, sample purity determinations and kinetics. 12

13. DSC differs fundamentally from DTA in that the sample and reference are both maintained at the temperature predetermined by the program. During a thermal event in the sample, the system will transfer heat to or from the sample pan to maintain the same temperature in reference and sample pans. 13

14. Differential Scanning Calorimetry – Principle of Operation A sample is placed inside a crucible which is then placed inside the furnace of the DSC system along with a reference pan which is normally empty (inert gas may be used). By applying a controlled temperature program (isothermal, heating or cooling at constant rates), phase changes can be characterized and/or the specific heat of a material can be determined. Heat flow quantities are calculated based on calibrated heat flow characteristics of the cell. 14

15. Two basic types of DSC instruments : Power compensation Heat-flux 15

16. Two major types of DSC instruments are available : Heat flux device – more popular; more stable baseline and more durable cell. Difference in heat flow into s and r is measured with (linear) change in sample temperature. Power compensation device – better resolution; faster heating and cooling rates. s and r heated by separate heaters to keep same temperature, as T is changed linearly. 16

17. 17 Power compensation DSC Heat flux DSC

18. References Rieger J. The glass transition temperature Tg of polymers—comparison of the values from differential thermal analysis (DTA, DSC) and dynamic mechanical measurements (torsion pendulum). Polymer testing. 2001 Oct 1;20(2):199-204. 18

19. Thank You 19