Introduction

 

Thermal analysis provides information on measurements of transition temperature (melting, crystallization, glass transition, liquid crystalline transition), enthalpy change associated with transition, reaction rate kinetics, thermal and oxidative stability, heat capacity, polymorphism, curing, softening and penetration behaviour, and relaxation process etc.

 

Thermogravimetric Analysis

Thermogravimetric Analysis (TGA) is a technique that monitors the mass of a substance as a function of temperature or time.  The monitored sample is subjected to a controlled temperature program in a controlled atmosphere. Upon heating the sample, its weight increases or decreases depending on the chemical reaction.

A TGA consists of a sample pan supported by a precision balance. That pan resides in a furnace and is heated during the experiment. The mass of the sample is monitored during the experiment. A sample purge gas controls the sample environment. This gas may be an inert or reactive gas that flows over the sample and exits through an exhaust.

 

Differential Scanning Calorimetry

Differential scanning calorimetry (DSC) is a technique that monitors heat effects associated with phase transitions and chemical reactions as a function of temperature. During DSC at the same temperature and pressure, the difference in heat flow to the sample and a reference is recorded as a function of temperature. The reference is an inert material such as an empty aluminium pan. The temperature of both the sample and reference are increased at a constant rate. This heat flow is equivalent to enthalpy changes.

The sample used is sealed into a small aluminium pan. The reference is usually an empty pan and cover. The pans hold up to about 10 mg of material.