Instruments and Techniques
The Cahn Thermax 500 Thermogravimetric Analyzer (TGA)
Thermo Fisher, Newington, USA
TGA is commonly employed in research and testing to determine characteristics of materials such as polymers to determine degradation temperatures, absorbed moisture content of materials, the level of inorganic and organic components in materials, decomposition points of explosives, and solvent residues. It is also often used to estimate the corrosion kinetics in high temperature oxidation.
The Cahn TherMax 500 TGA system specializes in demanding applications where high temperatures, pressures, and aggressive atmospheres are required. Pressure can be used to enhance or speed up reactions. The Cahn Thermax 500 thermogravimetric analyzer measures weight changes of sample over a given temperature and pressure range under specific environmental conditions.
Furnace temperature follows a temperature profile sequence established by the user in a method in the Thermax software. The software periodically records weight and pressure measurements and stores them on the computer.
After the measurement cycle or “run” is completed, the data file can be processed in the Analysis mode of the software. Raw or processed data may be plotted on the monitor display or on a graphics plotter, printed in tabular form, or copied on a separate diskette for archiving.The three parts of the Thermax 500 are the:
- Mainframe - the instrument hardware which includes: pressure balance, furnace vessel, stand and elevator.
- Console - which: houses the instrument electronics, displays data and warnings and connects the Thermax with the computer.
- Pressure/Flow Controller - which: controls pressure in the instrument, controls flow for three (3) gases and indicates pressure in the instrument.
- The furnace follows a precise temperature profile of ramps and isotherms, established by the user, under constant computer control.
- Gas flow and pressure is controller by a pressure/flow controller.
- Time, weight and temperature data are acquired at defined intervals and the data is stored on the computer's hard disk.
- Cahn's Thermax software allows you to edit and perform analytical functions on your run data. A permanent record of the raw data or the processed data can be made by printing in tabular form or copying to a diskette.
|Maximum Weight||±10 g|
|Temperature Drift||10 µg/°C|
|Accuracy at ambient temperature||<0.02%|
|at ambient pressure||Up to 1100°C|
|at 1000 psi||Up to 1000°C|
|Maximum Heating Rate||25°C/min|
|Temperature Repeatability||± 3°C|
|Maximum pressure at 25°C||1500 psi|
|Maximum pressure at 1000°C||1000 psi|
|Internal Volume||0.3 liters|
|Atmospheres||Static or dynamic gases including H2O, alcohols, adelhyde, ketones, alkanes, dilute acids, H2, CO2.|