Thermal Analysis

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 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 Sample is heated at a constant heating rate Samples Property Measured Wt

Size Heat Flow Temp Gas evolved TGA TMA DSC DTA TPD TGA Constant Heating Rate Initial Temp Final Temp

Heating Rate (C/min) Data Weight vs Time Weight vs Temp. Differential This Data (DTG) DSC 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 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 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 TMA Polymer with glass transition

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 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 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(C204)*xH2O Different Heating Rates 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 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 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 ZrO2 (s) +2 SO2 (v) 15 H2O 5 SO2 Water Loss

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1

2 Wt. Loss 18.0152 36.0304 54.0456 72.0608 90.076 108.0912 126.1064 144.1216 162.1368 180.152 198.1672 216.1824 234.1976

252.2128 270.228 64.0588 128.1176 % loss 1.721573 3.443146 5.164719 6.886292 8.607865 10.32944 12.05101 13.77258 15.49416 17.21573

18.9373 20.65887 22.38045 24.10202 25.82359 31.9452 38.0668