Thermal analysis
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Thermal Analysis. Terry A. Ring Chemical Engineering University of Utah. Different Techniques. Thermometric Titration (TT) Heat of mixing Thermal Mechanical Analysis (TMA) Thermal Expansion Coefficient Dynamic Mechanical Analysis (DMA) Viscoelastic Properties

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Thermal Analysis

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Thermal analysis

Thermal Analysis

Terry A. Ring

Chemical Engineering

University of Utah


Different techniques

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)


Basic principle

Basic Principle

  • Sample is heated at a constant heating rate

  • Sample’s Property Measured

    • Wt TGA

    • SizeTMA

    • Heat FlowDSC

    • TempDTA

    • Gas evolvedTPD


Thermal analysis

TGA

  • Constant Heating Rate

    • Initial Temp

    • Final Temp

    • Heating Rate (°C/min)

  • Data

    • Weight vs Time

    • Weight vs Temp.

  • Differential This Data (DTG)


Thermal analysis

DSC


Thermal analysis

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


Thermal analysis

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


Dta dtg

DTA + DTG


Thermal analysis

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


Thermal analysis

TMA

Polymer with glass transition


Thermal analysis

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


We have tga only

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


Thermal analysis

TGA

  • Constant Heating Rate

    • Initial Temp

    • Final Temp

    • Heating Rate (°C/min)

  • Data

    • Weight vs Time

    • Weight vs Temp.

  • Differential This Data (DTG)


Tga ca c 2 0 4 xh 2 o

TGA – Ca(C204)*xH2O


Different heating rates

Different Heating Rates


Heating rate

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


Precipitated zr 5 o 8 so 4 2 15 h 2 o

Precipitated Zr5O8(SO4)2*15 H2O

This sample was dried fro 48 hrs at 110C before TGA analysis.

What is going on?


Analysis of filtrate from precipitation

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)


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