Thermogravimetric Analysis

TGA
Projected availability: Fall 2021

Thermogravimetric analysis (TGA) uses heat to force reactions and physical changes in materials . TGA provides quantitative measurement of mass change in materials associated with transition and thermal degradation. TGA records change in mass from dehydration, decomposition, and oxidation of a sample with time and temperature. Characteristic thermogravimetric curves are given for specific materials and chemical compounds due to unique sequence from physicochemical reactions occurring over specific temperature ranges and heating rates. These unique characteristics are related to the molecular structure of the sample.

Data Output & Analysis

TGA gives a mass vs. temperature plot. The absolute value of the derivative of mass vs. temperature is known as “DTG”, and can also be plotted against temperature. The degradation temperature of samples can be found from the largest value of DTG (point of fastest degradation). The 5%, 50%, and 99% mass lost temperatures (where applicable) can be determined from the initial mass. The primary component of initial weight loss is usually evaporation of moisture and other volatiles. At larger values of weight loss weight loss the primary factors are typically pyrolysis, reduction, and desorption. While both inert ([math]\displaystyle{ N_2 }[/math] or noble gas) and oxidizing ([math]\displaystyle{ O_2 }[/math]) atmospheres can be used for TGA, the inert atmosphere is often preferred so it doesn’t interact with the sample and cause unwanted weight gain, potentially ruining any data collected.