thermal analysis-tg-dta
DESCRIPTION
It is the slide prepared by me to explain TG -DTA in short in SAC-7 seminar , at manuguru AP.TRANSCRIPT
PRINCIPLE, INSTRUMENTATION
AND APPLICATIONS OF
THERMAL ANALYSIS
Group -1Team members: Rampravesh, Nibedita, Balraj, Periyasamy, Durgakishore, M.S Dhar,
S.Chatterjee , V.G.Prabhu
Seminar by : Vijaykumar S MarakattiPoornaprajna Institute of Scientific research, Bangalore
Outline of talk
Introduction to Thermal Analysis
Thermo Gravimetric Analysis -TGA
Differential Thermal Analysis- DTA
Differential Scanning Calorimetry -DSC
Applications
IntroductionChange in physical properties of water with increase in temperature
Applied thermal analysis techniques
Heat
Change in physical property
Thermo Gravimetric Analysis
Mass
ΔT
Differential Thermal Analysis
ΔH
Differential Scanning Analysis.
DeformationDynamic
Mechanical Analysis
Physical Properties
Evolved Gas Analysis Gas
decomposeThermal diffusivity
Laser Flash Analysis
volumeDilatometry
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)
Thermal Gravimetric Instrument
Furnace
Balance- hang down here
Auto sampler
Thermocouple
Gas flow
Crucible
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.
Decomposition of CaCO3 at different gas atmosphere
Effect of gas atmosphere and crucible on TG
Decomposition of CaCO3 using different crucible
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.
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
Differential Thermal Analysis (DTA) Instrument
Endothermic - heat flows into the sample.Exothermic - heat flows out of the sample.
Interpretation of DTA
ΔH = K * Peak area
K - can be determined by measuring the ΔH and peak area of know metals
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.
Differential Scanning Calorimeter(DSC) Heat flux
Power Compensation DSC Cell
ApplicationsPolymer industryFood industry
Pharma industry Research and development
Ceramic industry
Cosmetic industry
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
Composition of a Rubber Sample
To determine Tg (glass transition temperature)of Polymers
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
Application in determination of phase transition
113 ̊ C Rhombohedral to monoclinic
124 C ̊Melting point
179 C ̊Liquid phase transistion
446 C̊Boiling point
Sulfur element
To find the melting and Boiling point of Materials
Benzoic acid
OPEN FOR DISCUSSION
TG ?..
DTA ??DSC ???ΔH ?
Calibration ?..DTG /DTA ???ΔT ?
sample ?
??....