Thermal Analysis Center

INTRODUCTION

The Thermal Analysis Center (TA Center) is a University of Minnesota External Sales Organization and Internal Sales Organization. The TA center contains instruments for studying the effect of temperature and environmental conditions on the physical, compositional and mechanical properties of materials.

Contact Prof. Lorraine Francis for more information. (lfrancis@umn.edu)

THERMAL ANALYSIS

Thermal analysis equipment may be operated by trained users from inside the University of Minnesota (internal sales) and outside (external sales). Operator assisted studies are also available.

THERMOGRAVIMETRIC ANALYZER (PERKIN ELMER TGA7)

• Measures the sample weight as a function of temperature in controlled atmosphere. Sensitivity: ± 0.1 µg
• Photo of equipment (TGA7.jpg)
• Specimen size: approximately 1 - 100 mg
• Temperature range: room temperature - 1000°C
• Heating rate: 0.1 - 200 °C/min
• Purge gases: nitrogen and air are available; others require prior arrangement
• Example applications: temperature of decomposition, thermal stability of polymers, weight change due to reaction with a gas

THERMOGRAVIMETRIC/DIFFERENTIAL THERMAL ANALYZER (PERKIN ELMER DIAMOND TG/DTA)

• Simultaneously measures the sample weight and difference in temperature from an inert standard as a function of temperature in controlled atmosphere. Sensitivity: ± 0.2 µg (TGA) and 0.06 µV (DTA)
• Photo of equipment (Tg-DTA.jpg)
• Specimen size: 200 mg maximum
• Temperature range: room temperature - 1500°C
• Heating rate: 0.01 - 100°C/min
• Purge gases: nitrogen and air are available; others require prior arrangement
• Example applications: kinetics of solid state reactions, crystallization temperatures and kinetics, decomposition reactions

STRESS MEASUREMENT APPARATUS

• The stress measurement apparatus is available for studies requested by outside users (external sales).
• Stress Measurement Apparatus
• Stress development in liquid applied coatings during drying and curing is estimated from measurement of deflection of a coated cantilever beam
• Schematic of equipment (stressapparatus.tif)
• Coating onto small cantilevers (steel, Si or glass) by blade (standard), wirewound rod or simple spreading. Final coating thickness typically 10 - 75 µm.
• Controlled drying conditions - airflow, relative humidity, atmosphere (air or nitrogen), temperature (room temperature standard, temperatures up to 100°C possible)
• UV curing port and lamp
• Video monitoring of coating appearance during drying and stress development
• Weight loss monitored in a separate experiment in the apparatus, under identical conditions
• References:
  • L. F. Francis, A. V. McCormick, D. M . Vaessen, and J. A. Payne, "Measurement and Development of Stress in Polymer Coatings," Journal of Materials Science, 37 4717-4731 (2002).
  • D. M . Vaessen, A. V. McCormick, and L. F. Francis, "Effects of Phase Separation on Stress Development in Polymeric Coatings," Polymer 43(8) 2267-2277 (2002).
  • J. A. Payne, A. V. McCormick and L. F. Francis, "A Study of Stress Development in Aqueous Gelatin Coatings," Journal Applied Polymer Science, 73 [4], 553-561 (1999).
  • J. A. Payne, A. V. McCormick, and L. F. Francis, "In Situ Stress Measurement Apparatus for Liquid Applied Coatings," Review of Scientific Instruments, 68 [10], 4564-4568 (1997).