1.1 This part of ISO 182 specifies a method for the determination of the thermal stability at elevated temperature of compounds and products based on vinyl chloride homopolymers and copolymers (in the following text abbreviated to PVC) which undergo dehydrochlorination (the evolution of hydrogen chloride).
1.2 The method is intended primarily as a simple and rapid quality-control test during the manufacture and conversion of PVC compounds. It may be used also for the characterization of PVC compounds and products.
It is suitable for coloured compounds and products where a discolouration test under the action of heat may be unsatisfactory.
1.3 The method is recommended for compounded materials and products only. It is not recommended for compounds in the form of dry blends since such materials may not be sufficiently homogeneous.
PVC compounds and products may evolve decomposition products in addition to hydrogen chloride at elevated temperatures. A limited number of these decomposition products may affect the time to colour change of the indicator paper. It is not possible to compensate for this effect within the scope of this part of ISO 182, and therefore care is necessary in comparing results for dissimilar compounds and products.