9.1 Introduction

A wide range of techniques have been applied to the elucidation of the thermal and chemical stability of polymers. Theses include:

• Thermogravimetric analysis (TGA)

• Differential thermal analysis (DTA)

• Differential scanning calorimetry (DSC)

• Thermal volatilisation analysis (TVA)

• Evolved gas analysis (EGA)

• Mass spectroscopic methods (MS)

Thermal analysis methods can be broadly defined as analytical techniques that study the behaviour of materials as a function of temperature [1]. These are rapidly expanding in both breadth (number of thermal analysis-associated techniques) and in depth (increased applications). Conventional thermal analysis techniques include DSC, DTA, TGA, thermomechanical analysis, and dynamic mechanical analysis (DMA). Thermal analysis of a material can be either destructive or non-destructive, but in almost all cases subtle and dramatic changes accompany the introduction of thermal energy. Thermal analysis can offer advantages over other analytical techniques including: variability with respect to application of thermal energy (step-wise, cyclic, continuous, etc.), small sample size, the material can be in any 'solid' form - gel, liquid, glass, solid, ease of variability and control of sample preparation, ease and variability of atmosphere, it is relatively rapid, and instrumentation is moderately priced. Most often, thermal analysis data are used in conjunction with results from other techniques.

Cerrada [2] has reviewed current trends in the thermal testing of polymers.

Some of the thermal and chemical stability applications to which these various techniques have been applied are summarised in Table 9.1.