1. Technical Support Bulletin
Faculty of Engineering
Issue No.30 September 2017
Author: Noor Fatihah Suhaimi, Analytical Unit, FOE
Thermal gravimetric Analysis (TGA) in UNMC
1. OVERVIEW
The Thermogravimetric Analyzer (TGA) is an essential laboratory tool used for material characterization. TGA is used as a technique to
characterize materials used in various environmental, food, pharmaceutical, and petrochemical applications.
Method: the mass of a sample is measured over time as the temperature changes.
In Engineering Research Building in UNMC, there are two types of TGA:
• Mettler Toledo TGA/DSC 1
• STA6000 Perkin Elmer – top loading TGA
TGA INFORMATION:
• loss of water
• loss of solvent
• loss of plasticizer
• Decarboxylation
• Pyrolysis
• Oxidation
• Decomposition
• Weight % filler
• Weight % ash.
2. SCHEMATIC DIAGRAM OF TGA
& SUPPORTING PARTS
The• mass of the sample is monitored
during the experiment. A sample purge
gas controls the sample environment.
This gas may be inert or a reactive gas
that flows over the sample and exits
through an exhaust.
• A TGA consists of a sample pan that is
supported by a precision balance. That
pan resides in a furnace and is heated
or cooled during the experiment.
Supporting• part for TGA/DSC: Coolant
used: Chiller 15 °C ≥ 35 °C. To ensure
temperature is within the safe range
(Diagram 5).
Gas• filter with silica gel and distilled
water: To filter possible harmful gas/
odor during analysis.
Gas• Flowmeter (Mettler Toledo): To
measure flow rate of gas in instrument
from pipeline during analysis.
A TGA thermal curve is displayed from
left to right. The descending TGA
thermal curve indicates a weight loss
occurred. A 15.013 mg sample of
calcium carbonate was analyzed.
Temperature Program = Heat from 100
°C to 900 °C @ 10 °C/minute in Nitrogen
atmosphere with a purge rate of 20
mL/minute.
Then, calculate the extrapolated onset
temperature that denotes the
temperature at which the weight loss
begins. We use the extrapolated onset
Temperature (To) because it is a
reproducible temperature calculation
and it is specified to be used by ASTM
E1131. The extrapolated onset
Temperature is 704.69 °C.
APPLICATIONS IN
EDUCATION & INDUSTRY:
1. Research & Development
2. Food Industry
3. Pharmaceutical
4. Polymer Industry
5. Ceramic, Cosmetic and Various
Industries
3. MEASUREMENT RESULT
(TGA-DTG)
The next calculation that is useful and
finalizes the characterization of calcium
carbonate is the peak calculation of the
1st derivative of the weight loss curve.
The 1st derivative curve is easily
displayed by selecting that option
under the MATH drop-down list. The
1st derivative peak temperature (Tp) is
789.03 °C. The peak of the first
derivative indicates the point of
greatest rate of change on the weight
loss curve. This is also known as the
inflection point.
6. REFERENCES
https://www.perkinelmer.com/CMSResources
http://www.andersonmaterials.com/tga.html
https://www.slideshare.net/VijayMarakatti/
thermal-analysistgdta
5. DATA EVALUATION & SOFTWARE
In STA6000, software used for data
evaluation is Pyris 10 whereas in TGA/DSC
1 Mettler Toledo is StarE Software.
Diagram 1: TGA DSC1 Mettler Toledo
Diagram 2: STA6000 Perkin Elmer
Diagram 3: TGA DSC 1 Mettler Toledo
Diagram 4: STA6000 Perkin Elmer
Diagram 5: Julabo chiller coolant
Diagram 8: Example of StarE Software for
Mettler Toledo.
Diagram 9: Example of Pyris 10 Software used
in STA6000 Perkin Elmer
Diagram 7: Loading sample in Mettler Toledo
4. TGA ANALYSIS REQUIREMENT:
Standard test method for TGA: ASTM
E1131.
Temperature : 25C to 1000C
Sample size: Nanoparticles, liquid, solid
Sample weight: 5mg to 30mg
Purge Gas: Nitrogen
Reactive Gas: Oxygen or Purified air
Gas flowrate: 10ml/min – 100ml/min
