Thermal Analysis.ppt

TGA. DTA. DSC

1. Thermal Analysis
Terry A. Ring
Chemical Engineering
University of Utah

2. Different Techniques
•Thermometric Titration (TT)
–Heat of mixing
•Thermal Mechanical Analysis (TMA)
–Thermal Expansion Coefficient
•Dynamic Mechanical Analysis (DMA)
–Viscoelastic Properties
•Differential Scanning Calorimetric (DSC)
–Heat flow during Transitions
•Thermal Gravimetric Analysis (TGA)
–Weight Loss due to decomposition
–Derivative Thermogravimetric Analysis (DTG)
•Differential Thermal Analysis (DTA)
–Heat of Transitions
•Temperature Programmed Desorption (TPD)
–Temperature at which gas is desorbed from (catalyst) surface
–Emission gas Thermoanalysis (EGT)

3. Basic Principle
•Sample is heated at a constant heating
rate
•Sample’s Property Measured
–Wt TGA
–Size TMA
–Heat Flow DSC
–Temp DTA
–Gas evolved TPD

4. TGA
•Constant Heating
Rate
–Initial Temp
–Final Temp
–Heating Rate (°C/min)
•Data
–Weight vs Time
–Weight vs Temp.
•Differential This Data
(DTG)

5. DSC

6. DSC
•Constant Heating Rate
–Initial Temp
–Final Temp
–Heating Rate (°C/min)
•Data
–Heat flow to sample minus
Heat flow to reference vs
Time (Temp.)
•Measures heat of
crystallization
Polymer without weight change in this temperature range

7. DTA
•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, e.g. nothing but latent heat
•Measures
–Heat of crystallization
–Glass Transition Temperature

8. DTA + DTG

9. TMA
•Constant Heating Rate
–Initial Temp
–Final Temp
–Heating Rate (°C/min)
•Data
–Size of Sample vs Time (or Temp.)
•Measures
–Thermal Expansion Coefficient
–Volume change on crystalization or crystal
transformations
–Sintering
–Glass Transitions in Polymers

10. TMA
Polymer with glass transition

11. DMA
•Constant Heating Rate
–Initial Temp
–Final Temp
–Heating Rate (°C/min)
•Data
–Force vs Time (or Temp.)
–Force delay vs Time (or
Temp.)
–Viscoelastic Properties
•Storage and Loss
Modulus
•Measures
–Glass Transition
–Viscoelastic Properties
Polymer with Glass Transition

12. We have TGA -only
•Heating a sample of Calcium oxalate
•Ca(C
20
4)*xH
2O Ca(C
20
4) *H
2O + x-1 H
2O
•Ca(C
20
4)*H
2OCa(C
20
4) + H
2O
•Ca(C
20
4) CaCO
3+ CO
•CaCO
3CaO + CO
2

13. TGA
•Constant Heating
Rate
–Initial Temp
–Final Temp
–Heating Rate (°C/min)
•Data
–Weight vs Time
–Weight vs Temp.
•Differential This Data
(DTG)

14. TGA –Ca(C
20
4)*xH
2O

15. Different Heating Rates

16. Heating Rate
•Heating Too Fast
–Overlaps Transitions
•Interpretation Problems
•Kinetics of Decomposition
–Sample Size
–Mass Transfer
•Convective Mass Transfer
•Pore Diffusion
–Heat Transfer
•Convective Heat Transfer
•Thermal Conductivity
–Porous solid

17. Precipitated Zr
5O
8(SO
4)
2*15 H
2O
This sample was dried fro 48 hrs at 110C before TGA analysis.
What is going on?

18. Analysis of Filtrate from
Precipitation
•Precipitation
•5ZrOCl
2+ 2H
2SO
4 + xH
2O 
Zr
5O
8(SO
4)
2*15 H
2O (s) + 10 HCl
•Decomposition
•Zr
5O
8(SO
4)
2*15 H
2O (s) 
Zr
5O
8(SO
4)
2*14 H
2O (s) + H
2O (v)
•Zr
5O
8(SO
4)
2 5
ZrO
2 (s) +2 SO
2 (v)15 H2OWater LossWt. Loss% loss
1 18.01521.721573
2 36.03043.443146
3 54.04565.164719
4 72.06086.886292
5 90.0768.607865
6 108.091210.32944
7 126.106412.05101
8 144.121613.77258
9 162.136815.49416
10 180.15217.21573
11 198.167218.9373
12 216.182420.65887
13 234.197622.38045
14 252.212824.10202
15 270.22825.82359
SO2 1 64.058831.9452
2 128.117638.0668