High-Pressure Thermogravimetric Analyzer and Thermogravimetry

High-pressure thermogravimetric analyzers are instruments that use thermogravimetric analysis (TGA) to detect the relationship between temperature and mass changes of substances. Thermogravimetric analysis is a technique that measures the mass of a substance as it changes with temperature (or time) under programmed temperature control. High-pressure thermogravimetric analyzers are widely used in various fields such as plastics, rubber, coatings, pharmaceuticals, catalysts, inorganic materials, metal materials, and composites for research and development, process optimization, and quality control.

Working Principle of High-pressure Thermogravimetric Analyzers

Under programmed temperature control, high-pressure thermogravimetric analyzers measure the relationship between the mass of a substance and its temperature (or time). When the substance being measured undergoes sublimation, vaporization, gas decomposition, or loses crystalline water during heating, its mass will change.

The most commonly used measurement principles are the displacement method and the null method. The displacement method relies on the proportional relationship between the deflection of the balance beam and mass changes, using a differential transformer to detect the deflection and automatically record it. The null method employs a differential transformer or optical method to determine the deflection of the balance beam, then adjusts the current in a coil installed in the balance system and magnetic field to restore the balance beam's deflection. Since the force applied by the coil's rotation is proportional to the mass change and the current in the coil is proportional to this force, measuring and recording the current change can yield a mass change curve.

The main components of high-pressure thermogravimetric analyzers include a thermal balance, which comprises a balance, furnace, programmed temperature control system, and recording system. Additionally, it includes a sample holder, thermocouple for temperature measurement, sensors, balance weight, damper, and balance restorer, as well as damping signals and other parts.

Characteristics of Thermogravimetric Analysis

An important characteristic of thermogravimetric analysis is its strong quantitative nature, accurately measuring both mass changes and the rate of these changes in a substance. This means that as long as the substance undergoes weight changes when heated, thermogravimetric analysis can be used to study its transformation process. It can be applied to investigate physical phenomena of substances such as changes in crystalline properties, melting, evaporation, sublimation, and adsorption. Additionally, it can be used to study chemical phenomena such as the thermal stability of substances, decomposition processes, dehydration, dissociation, oxidation, reduction, quantitative analysis of components, the impact of additives and fillers, moisture and volatiles, and reaction kinetics.