Thermogravimetric Analysis
Thermogravimetric Analysis (TGA) · Also known as: TGA, thermal gravimetry, thermogravimetry
Thermogravimetric Analysis (TGA) is a thermal characterization technique that continuously measures mass loss or gain of a material as a function of temperature (or time at constant temperature). Developed systematically by William Wendlandt and colleagues in the 1960s, TGA identifies thermal transitions (evaporation, decomposition, oxidation, reduction) and quantifies composition of polymers, pharmaceuticals, ceramics, and other materials. The derivative signal (DTG) highlights transition temperatures. When combined with gas analysis (MS, FTIR), decomposition products are identified.
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When to use it
TGA is essential for quantifying thermal decomposition, assessing polymer purity, measuring moisture content, and studying kinetics of thermal degradation. Apply when composition-dependent mass loss distinguishes phases (e.g., hydroxides vs. oxides; volatile impurities). Most useful for temperature range up to ~1000°C (higher with special furnaces). Limit: cannot identify products directly; couple with MS or FTIR for identification.
Strengths & limitations
- Quantifies water content, volatile impurities, and thermal stability in one measurement
- Sensitive balance enables detection of <1% mass loss with high precision
- Simultaneously measures multiple transitions; clear separation if temperature-dependent
- Rapid results (1-hour thermal ramp) with minimal sample (~5 mg)
- Kinetic analysis yields activation energies and reaction orders for thermal processes
- Does not identify decomposition products directly; requires MS/FTIR coupling
- Kinetic analysis assumes specific reaction model; different models may fit data equally well
- Furnace heating creates thermal gradients; outer sample hotter than interior
- Volatile products from decomposition may not escape quickly; kinetics slow artificially
- Baseline drift near high temperatures limits accuracy of small mass-change detection
Frequently asked
What heating rate should I use?
Standard: 10 K/min under nitrogen for decomposition. Faster rates (20-50 K/min) reduce furnace thermal lag; slower rates (1-5 K/min) improve kinetic accuracy. Higher rates shift apparent decomposition temperature higher (kinetic effect). Use consistent rate for comparability.
How do I distinguish water loss from decomposition?
Water evaporates ~50-150°C (reversible). Coupling with mass spectrometry identifies H2O directly. Drying at 105°C removes surface water; baking to higher T reveals crystal water.
What does DTG (derivative thermogravimetry) show?
DTG is the first derivative of mass with respect to temperature: dM/dT. It sharpens features, making transition temperatures (peak) and rates (peak height) more visible. DTG peaks occur at steepest parts of TG curve.
How do I extract kinetic parameters from TGA data?
Use isothermal TGA (fixed temperature, measure mass vs. time) or non-isothermal (ramp, measure mass vs. temperature). Fit to kinetic models (first-order, Avrami, autocatalytic); extract activation energy via Arrhenius plot (ln(rate) vs. 1/T).
Sources
- Wendlandt, W. W. (1986). Thermal Analysis (3rd ed.). John Wiley & Sons. link ↗
- Haines, P. J. (Ed.). (2012). Principles of Thermal Analysis and Calorimetry (2nd ed.). Royal Society of Chemistry. link ↗
- Vyazovkin, S., et al. (2020). ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochimica Acta, 689, 178597. DOI: 10.1016/j.tca.2020.178597 ↗
How to cite this page
ScholarGate. (2026, June 3). Thermogravimetric Analysis (TGA). ScholarGate. https://scholargate.app/en/materials-science/thermogravimetric-analysis
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
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