thermal analysis-tg-dta

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 ?

??....