The document discusses various thermal analysis techniques including thermometric titration, thermal mechanical analysis, dynamic mechanical analysis, differential scanning calorimetry, thermal gravimetric analysis, and differential thermal analysis. It provides details on thermal gravimetric analysis and differential thermal analysis, describing the basic principles, data collection, and analysis of results for these methods. An example is given analyzing the thermal decomposition of calcium oxalate dihydrate using thermal gravimetric analysis.

1. Thermal Analysis

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
– Temp DTA

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. 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. Alumina
• Measures
– Heat of crystallization
– Glass Transition Temperature

6. DTA + DTG

7. We have TGA - only
• Heating a sample of Calcium oxalate
• Ca(C204)*xH2O  Ca(C204) *H2O + x-1 H2O
• Ca(C204)*H2O Ca(C204) + H2O
• Ca(C204)  CaCO3 + CO
• CaCO3  CaO + CO2

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

9. TGA – Ca(C204)*xH2O

10. Different Heating Rates

11. 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

12. Precipitated Zr5O8(SO4)2*15 H2O
This sample was dried fro 48 hrs at 110C before TGA analysis.
What is going on?

13. Analysis of Filtrate from
Precipitation
• Precipitation
• 5ZrOCl2 + 2H2SO4 + xH2O 
Zr5O8(SO4)2*15 H2O (s) + 10 HCl
• Decomposition
• Zr5O8(SO4)2*15 H2O (s) 
Zr5O8(SO4)2*14 H2O (s) + H2O (v)
• Zr5O8(SO4)2  5
ZrO2 (s) +2 SO2 (v)
15 H2O Water Loss Wt. Loss % loss
1 18.0152 1.721573
2 36.0304 3.443146
3 54.0456 5.164719
4 72.0608 6.886292
5 90.076 8.607865
6 108.0912 10.32944
7 126.1064 12.05101
8 144.1216 13.77258
9 162.1368 15.49416
10 180.152 17.21573
11 198.1672 18.9373
12 216.1824 20.65887
13 234.1976 22.38045
14 252.2128 24.10202
15 270.228 25.82359
SO2 1 64.0588 31.9452
2 128.1176 38.0668