Diffrential Thermal Analysis (DTA)

Instrumentation of DTA

1. Instrumentation of DTA Maheen Zahra (1300143) BS IV (8 th )

2. Contents Differential thermal analysis Apparatus P rocedure Graphical representation Advantage of DTA

3. Differential thermal analysis In Differential Thermal Analysis, the temperature difference that develops between a sample and an in reference material is measured, when both are subjected to identical heat treatments.

4. INSTRUMENTATION

5. APPARATUS 1.Sample holder comprising thermocouples, sample containers and a ceramic or metallic block. 2.Furnace. 3.Temperature programmer 4.Recording system

6. Procedure Heart of the analysis – heating block Identical pair of cavities for the sample, ref. material Whole unit is set in an oven- control pressure Thermocouple is place directly in contact with the sample and another in contact with the reference

7. Temperature of the block is raised, the temperature of the sample & reference follow Zero temp. difference – no physical or chemical change If any reaction – difference in ∆T

8. Graphical Representation

9. NOTE.. Sharp Endothermic–changes in crystallinity or fusion Broad endotherms-dehydration reaction Physical changes usually result in endothermic curves Chemical reactions are exothermic

10. Sharp endotherm: crystalline rearrangemets , fusion, solid state transition Broader endotherm: dehydration, melting of polymers, slow reactions Narrow exotherm : crystallization Sharp exotherm : phase change

11. Advantage of DTA Instruments can be used at very high temperatures • instruments are highly sensitive •characteristic transition or reaction temperatures can be accurately determined.

12. REFERENCES https://www.slideshare.net/WilwinEdara/dsc-and-dta https://www.phase-trans.msm.cam.ac.uk/2002/Thermal1.pdf https://www.slideshare.net/shaisejacob/differential-thermal-analysis-dta-ppt

13. https://www.slideshare.net/KhawarYaqoob/differential-thermal-analysis-61206721 https://www.slideshare.net/sureshselvaraj108/differential-thermal-analysis