Analysis of degradation products by thermal volatilization analysis at subambient temperatures

In the subambient thermal volatilization analysis (TVA) technique, degradation products initially at −196°C are allowed to warm up to ambient temperature in a controlled manner under vacuum conditions, and volatilization from the sample tube to a trap at −196°C is monitored by means of a Pirani gauge. The technique is discussed in relation to earlier TVA work in which volatilization from a heated polymer sample was followed. Design and operation of a subambient TVA system are described, and examples of the application of the technique to the study of the degradation products of seven polymers are considered.