Thermal Gravimetric Analysis (TGA)

Introduction

Thermal Gravimetric Analysis (TGA) is a technique used to measure the change in weight of a material as a function of temperature or time under controlled heating conditions. It is commonly used in materials science, chemistry, and other fields to characterize the thermal stability, decomposition, and degradation of various materials.

In TGA, a sample is placed in a controlled heating environment, typically a furnace, and the weight of the sample is measured continuously as the temperature is increased. The change in weight is recorded as a function of temperature or time, and can be used to determine important properties of the sample, such as the onset and completion of thermal decomposition or the thermal stability of the material.

TGA is a useful analytical tool for a variety of applications, including the study of polymers, pharmaceuticals, minerals, and other materials. It can provide valuable information about the thermal behavior of these materials, such as their decomposition temperatures, kinetics of decomposition, and thermal stability under different conditions. TGA can also be used to monitor changes in the composition of a material, such as the release of gases or volatiles during heating.

Principle of TGA | Thermogravimetric Analysis Principle

The principle of TGA is “Loss of weight of the material is a function of time and temperature under controlled atmosphere”.Its heating range is 50 to 1500°C and heating rate is 0 to 200°C.

The principle of Thermal Gravimetric Analysis (TGA) is based on the measurement of the change in weight of a material as a function of temperature or time under controlled heating conditions. When a sample is heated, it undergoes a variety of physical and chemical changes, such as melting, sublimation, decomposition, and oxidation, which can result in a change in its weight.

TGA typically involves heating a sample at a constant rate, typically between 5 to 20 degrees Celsius per minute, in a controlled atmosphere, such as air, nitrogen, or an inert gas. As the sample is heated, its weight is continuously measured by a sensitive balance, such as a microbalance, with an accuracy of 0.1 micrograms or better.

The change in weight of the sample is recorded as a function of temperature or time, and can be used to determine important properties of the sample, such as its thermal stability, decomposition temperature, and kinetics of decomposition. The onset and completion of thermal decomposition can be determined from the inflection points in the TGA curve, and the rate of decomposition can be calculated from the slope of the curve.

TGA can also be used to study the composition of a material, such as the release of gases or volatiles during heating. The evolved gas can be analyzed by coupling the TGA with a mass spectrometer or infrared spectroscopy to identify the nature of the gas or volatile released during the thermal decomposition.

In thermogravimetric analysis (TGA), a sample is continually weighted while heating, as an inert gas atmosphere is passed over it. Many solids undergo reactions that evolve gaseous byproducts. In TGA, these gaseous byproducts are removed and changes in the remaining mass of the sample are recorded.

TGA Curve Interpretation | Thermogravimetric Curve

Procedure of Thermal Gravimetric Analysis | TGA Test Procedure

The procedure of thermal gravimetric analysis (TGA) typically involves the following steps:

1. Sample preparation: The sample is typically ground into a fine powder and placed in a small crucible. The crucible is then weighed to determine the initial weight of the sample.
2. Heating the sample: The crucible containing the sample is placed in the TGA instrument, which then heats the sample at a constant rate. The rate of heating can be controlled to suit the requirements of the analysis.
3. Measuring weight loss: As the sample is heated, it undergoes various chemical and physical changes, which can result in weight loss. The TGA instrument continuously measures the weight of the sample and records the weight loss as a function of temperature.
4. Analysis of the data: The TGA data can be analyzed to determine the thermal stability, composition, and other properties of the sample. The data can be used to calculate the weight loss, rate of weight loss, and other parameters.

Overall, the TGA procedure is relatively straightforward and can be completed in a few hours, depending on the rate of heating and the complexity of the analysis. The technique is widely used in materials science, chemistry, and engineering to study the thermal behavior of materials and to identify the presence of different chemical groups in the sample.

Uses of TGA | Thermal gravimetric analysis applications

Thermal gravimetric analysis (TGA) is a powerful analytical technique that is used to study the thermal stability and composition of materials. Here are some of the common uses of TGA:

1. Determination of thermal stability: TGA is used to determine the thermal stability of materials. By subjecting a material to a range of temperatures, TGA can identify the temperature at which the material begins to decompose or lose weight.
2. Quantitative analysis: TGA can be used to determine the amount of a particular substance in a sample. By measuring the weight loss of a sample as it is heated, TGA can determine the percentage of a particular component in the sample.
3. Characterization of polymers: TGA is widely used in the characterization of polymers, particularly in the determination of their thermal stability, decomposition behavior, and composition.
4. Analysis of organic and inorganic compounds: TGA is used to study the thermal behavior of organic and inorganic compounds. By analyzing the weight loss of a sample as it is heated, TGA can identify the presence of different chemical groups in the sample.
5. Evaluation of catalysts: TGA can be used to evaluate the activity of catalysts by measuring the weight loss of the catalyst as it is exposed to reactants.
6. Quality control: TGA can be used in quality control applications to ensure the purity and consistency of materials. By comparing the weight loss of a sample to a reference material, TGA can determine if the sample meets the required specifications.

Overall, TGA is a versatile analytical technique that has a wide range of applications in materials science, chemistry, and engineering.

Frequently Asked Questions

Thermogravimetric analysis notes | Thermal Gravimetric Analysis PDF | Thermal Gravimetric Analysis Applications | Thermogravimetry | Thermogravimetric analysis | Thermal Gravimetric Analysis PPT | Thermal Gravimetric Analysis Procedure | TGA Analysis Interpretation | TGA Analysis Principal