Thermal analysis-TG-DTA


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It is the slide prepared by me to explain TG -DTA in short in SAC-7 seminar , at manuguru AP.

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Thermal analysis-TG-DTA

  1. 1. PRINCIPLE, INSTRUMENTATION AND APPLICATIONS OF THERMAL ANALYSIS Group -1 Team members: Rampravesh, Nibedita, Balraj, Periyasamy, Durgakishore, M.S Dhar, S.Chatterjee , V.G.Prabhu Seminar by : Vijaykumar S Marakatti Poornaprajna Institute of Scientific research, Bangalore
  2. 2. Outline of talk  Introduction to Thermal Analysis  Thermo Gravimetric Analysis -TGA  Differential Thermal Analysis- DTA  Differential Scanning Calorimetry -DSC  Applications
  3. 3. Introduction Change in physical properties of water with increase in temperature
  4. 4. Applied thermal analysis techniques Heat Change in physical property
  5. 5. Thermo Gravimetric Analysis Mass ΔT Differential Thermal Analysis ΔH Differential Scanning Analysis. Deformation Dynamic Mechanical Analysis Physical Properties Evolved Gas Analysis Gas decompose Thermal diffusivity Laser Flash Analysis volumeDilatometry
  6. 6. Thermo gravimetric analysis (TGA)  It is an analysis, the mass of sample is recorded continuously as its temperature is increased linearly from ambient to high temperature.  Mass of material a functions of temperature. Processes occurring without change in mass (e.g.- Physical transitions ) cannot be studied by TG. Reactant(s)  Product(s) + Gas (a mass loss) Gas + Reactant(s)  Product(s) (a mass gain)
  7. 7. Thermal Gravimetric Instrument Furnace Balance- hang down here Auto sampler Thermocouple Gas flow Crucible
  8. 8. Best practices for Thermal Analysis Removal of absorbed water by drying.  Use purge gas (N2or He) to remove corrosive off-gases  Use samples with narrow grain size distribution.  For measurement in vacuum, sample Grain size > 60 mesh Calibration using the - Curie Temperature. -Standard compounds.  Keep the constant heating rate, same gas atmosphere and crucible for the analysis.
  9. 9. Decomposition of CaCO3 at different gas atmosphere Effect of gas atmosphere and crucible on TG Decomposition of CaCO3 using different crucible
  10. 10. Three factors should be noted when you get a TG curve: 1. General shape. 2. The particular T at which changes in mass occur. 3. The magnitudes of the mass changes.
  11. 11. Differential Thermal Analysis(DTA)  Heat absorbed or emitted by sample is observed by measuring the temperature difference between that sample and reference compound as temperature of both are increased. ΔT =TS-Tr as function of Temperature. ΔT ΔH - Qualitative. ΔT Temperature of furnace
  12. 12. Differential Thermal Analysis (DTA) Instrument Endothermic - heat flows into the sample. Exothermic - heat flows out of the sample.
  13. 13. Interpretation of DTA ΔH = K * Peak area K - can be determined by measuring the ΔH and peak area of know metals
  14. 14. Limitations of Differential Thermal Analysis (DTA)  ΔT determined by DTA is not so accurate (2-3 ̊C).  Small change in ΔT cannot be determined and quantified.  Due to heat variation between sample and reference makes, it less sensitive. To improve the above limitations change in the methodology is required.
  15. 15. Differential Scanning Calorimeter(DSC) Heat flux
  16. 16. Power Compensation DSC Cell
  17. 17. Applications Polymer industryFood industry Pharma industry Research and development Ceramic industry Cosmetic industry
  18. 18. V.S.Marakatti et. al .RSC Adv., 2013,3, 10795-10800 Stability of the Materials Sn(OH)Cl - Catalyst 200 ̊ C- Dehydration 200-400 ̊ C- Dehydroxylation 400-550 ̊̊C – Formation of oxide
  19. 19. Composition of a Rubber Sample
  20. 20. To determine Tg (glass transition temperature) of Polymers
  21. 21. Application in Food Industry Standard TGA results for Double mint chewing gum sample TGA auto stepwise results for Double mint chewing gum sample The correct combination of the gum formulation. Elastomers, glycerin, softening agents, and carbonates, flavoring agents, poly vinyl acetate
  22. 22. Application in determination of phase transition 113 ̊ C Rhombohedral to monoclinic 124 ̊C Melting point 179 ̊C Liquid phase transistion 446 ̊C Boiling point Sulfur element
  23. 23. To find the melting and Boiling point of Materials Benzoic acid
  24. 24. OPEN FOR DISCUSSION TG ?.. DTA ?? DSC ???ΔH ? Calibration ?.. DTG /DTA ???ΔT ? sample ? ??....