Introduction to Thermogravimetric Analysis (TGA)
Thermogravimetric analysis (TGA) is a less expensive, faster, and easier-to-use technique for determining the composition of various substances. TGA is an effective technique for determining the heat stability of materials, particularly polymers. This approach measures variations in the weight of a specimen as its temperature increases. TGA is a method of determining the overall mass of a sample as a temperature-dependent property. It is a fundamental property of many materials to undergo mass change as a function of temperature due to degradation and loss of volatile components. This phenomenon can provide vital information about materials under test. In this destructive technique, the mass of a sample is measured as a function of temperature or time. In testing labs, TGA is used to investigate thermal properties, such as a material’s melting point, decomposition temperature, and vaporization rate. TGA provides a statistical readout of material mass as a function of temperature and time. Thermogravimetric analysis is often done in combination with other techniques, such as differential scanning calorimetry (DSC) and thermomechanical analysis (TMA), to gain a more comprehensive understanding of the thermal properties of material samples. The sample is heated at a controlled rate in a specific atmosphere for thermogravimetric analysis. The substance’s weight variation is noted in temperature and time. MaTestLab is one of the best testing service providers, with the best network of testing laboratories in the USA to carry out TGA for our clients.
Principle and Methodology of Thermogravimetric Analysis (TGA)
When a material is subjected to heat, its mass changes due to physical or chemical changes in the material. This change in mass can be measured using an analytical balance or other suitable instrument. The mass changes are then plotted against temperature or time to generate a thermogravimetric curve which can be used to analyze the thermal behavior of the material.
TGA samples are typically heated at a constant rate while their mass is measured at regular intervals. The sample is usually placed on an open-air platform, which is heated by an external source such as an oven or furnace. As the sample heats up, its mass decreases due to physical or chemical changes in the material, resulting in loss of volatile components such as moisture, solvents, and gases. The rate of mass loss can be used to calculate various thermal properties of the sample such as decomposition temperature and vaporization rate.
Uses of Thermogravimetric Analysis (TGA)
TGA is used in pharmaceuticals, polymers, ceramics, food processing, petrochemicals, and environmental sciences industries. In polymers, it can be used to analyze additives such as plasticizers and stabilizers, which may affect polymer performance under different conditions. In pharmaceuticals, it is often used for quality control purposes, such as measuring drug content and purity levels in tablets or capsules before they are released for sale. In ceramics, it can be used for studying sintering behavior during firing processes, while in food processing, it can measure water content in food products before they are packaged for sale, and in petrochemicals, it can measure oil content levels in crude oil samples before refining processes begin. In environmental sciences, TGA can be used to measure organic carbon levels present in soil samples.
Advantages of Thermogravimetric Analysis (TGA)
The major advantage of TGA over other thermal analysis techniques is that it does not require any contact with the sample, making it particularly useful for studying materials that are sensitive to contamination from outside sources. TGA can be used on samples with small amounts of volatile components without requiring special preparation techniques such as freeze drying or vacuum drying, which may alter the studied sample’s properties. Also, TGA provides detailed information about both physical and chemical changes occurring during heating.
Disadvantages of Thermogravimetric Analysis (TGA)
TGA is unable to actively confirm the presence of a certain chemical. Verification is only indirect because a change in mass is explained using prior knowledge of that substance’s temperature-dependent response. TGA cannot provide information about what specific components are lost during heating experiments since only total mass losses are measured rather than individual component losses (e.g., moisture vs solvents). If volatile components are present at very low concentrations (<1%), TGA may not detect them due to sensitivity limitations associated with some instruments available on the market today. In case multiple components are present in a sample with similar thermal behavior, their individual contributions may not be distinguishable when plotting thermogravimetric curves.
Techniques Related to TGA
TGA is related to techniques including Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis Fourier Transform Infrared Spectroscopy (TGA-FTIR), and Evolved Gas Analysis (EGA).
