Working Principle of Thermogravimetric Analysis (TGA): Methods, Instrumentation, and Applications
Thermogravimetric Analysis (TGA) is a thermal analysis technique that continuously measures the mass of a specimen as it is heated, cooled, or held at a constant temperature in a controlled atmosphere. Mass changes reveal decomposition temperatures, compositional information, moisture content, volatile release, and thermal stability—fundamental data for material characterization across the polymer, pharmaceutical, ceramic, food, and energy industries. For companies seeking TGA testing at a US-based ASTM testing lab, Infinita Lab provides comprehensive thermal analysis through its accredited laboratory network.
How TGA Works
A precision microbalance continuously weighs a small specimen (typically 5–50 mg) placed in a crucible within a temperature-controlled furnace. The furnace heats the specimen at a programmed rate (typically 5–20°C/min) from ambient to temperatures up to 1,000–1,500°C. A purge gas (nitrogen for inert atmosphere, air, or oxygen for oxidative conditions) flows through the furnace. The resulting thermogravimetric curve plots mass (or mass percentage) versus temperature, revealing step-wise mass losses corresponding to specific decomposition events.
Key TGA Measurements
Decomposition Temperature
The onset temperature of weight loss indicates thermal stability limits. Multiple weight loss steps reveal sequential decomposition events—for example, moisture loss, polymer decomposition, and filler content in a composite sample.
Compositional Analysis
ASTM E1131 uses TGA to determine moisture, volatile content, polymer or organic content, carbon black, and inorganic filler/ash content in a single experiment by heating through progressive temperature stages in different atmospheres.
Proximate Analysis
TGA performs proximate analysis of fuels and coals (moisture, volatile matter, fixed carbon, ash) per ASTM D7582, replacing time-consuming furnace methods with a single automated analysis.
Applications
TGA serves polymer composition verification and quality control, pharmaceutical excipient and API stability assessment, ceramic and glass batch composition analysis, food product moisture and composition analysis, and rubber and composite filler content determination.
Infinita Lab: Your Material Testing Partner
Contact Infinita Lab for TGA Testing and enjoy major benefits like end-to-end testing management, faster turnaround, and reduced administrative burden. Gain confidence in accurate results and reduced stress in vendor coordination. Enhance your reputation for product reliability and innovation. Engineers and R&D managers can focus on core work rather than testing logistics.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote
Frequently Asked Questions (FAQs)
What does TGA measure? TGA measures mass changes in a specimen as a function of temperature and time in a controlled atmosphere, revealing decomposition, evaporation, oxidation, and compositional information.
What ASTM standards cover TGA testing? ASTM E1131 (compositional analysis), ASTM E1868 (loss-on-drying), ASTM E2550 (thermal stability), ASTM D7582 (proximate analysis of fuels), and ASTM E2403 (sulfated ash by TGA) are key TGA standards.
What sample size is needed for TGA? Typical sample sizes range from 5 to 50 mg. Smaller samples provide sharper resolution of overlapping weight loss events; larger samples improve detection of minor components.
What is the difference between TGA in nitrogen versus air? Nitrogen provides an inert atmosphere for thermal decomposition without oxidation. Air or oxygen allows oxidative degradation, enabling distinction between pyrolysis and combustion products and determination of carbon black content.
Can TGA identify unknown materials? TGA provides compositional fingerprints (decomposition temperatures and weight loss percentages) that help identify material classes. Combined with DSC and FTIR (TGA-FTIR), it provides more definitive identification of unknowns.
