1.1 This part of IS0 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 as PVC) which undergo
dehydrochlorination (the evolution of hydrogen chlorde).
1.2 The method may be used as a quality control
test during manufacture and conversion of PVC compounds.
It may also be used for the characterization
of PVC compounds and products, especially with regard
to the effectiveness of their heat-stabilizing systems.
It is suitable for coloured PVC compounds and products
where a discolouration test under the action of
heat may be unsatisfactory.
1.3 The method is recommended for compounded
PVC materials and products only, although it can be
used for polymers in powder form under appropriate
conditions, to be agreed upon between the interested
parties. The method is not recommended for PVC
compounds in the form of dry blends, since such
materials may not be sufficiently homogeneous.
1.4 PVC compounds and products may evolve other
decomposition products, in addition to hydrogen
chloride, at elevated temperatures. A limited number
of these decomposition products may affect the conductivity
of water when they are absorbed into it.
Compensation for this effect is not within the scope
of this part of IS0 182, and therefore care is necessary
in attempting to compare results for dissimilar
compounds and products. In this case a method suitable
for the determination of chloride ion (Cl-) in the
absorbing solution shall be used (see IS0 182-4).
1.5 The method may also be applied to other plastics
materials which can evolve hydrogen chloride or
other hydrogen halides when heated under the conditions
prescribed by the relevant specifications, or as
agreed upon between the interested parties.
Dieser Teil von ISO 182 legt ein Verfahren zur Bestimmung der thermischen Stabilität bei erhöhter Temperatur von Formmassen und Erzeugnissen fest, die auf der Grundlage von Vinylchlorid-Homopolymeren und -Copolymeren (im folgenden Text abgekürzt als PVC) hergestellt sind und die zum Verlust an Wasserstoffchlorid neigen (Entwicklung von Wasserstoffchlorid). Das Verfahren kann zur Qualitätskontrolle während der Herstellung und Umwandlung von PVC-Formmassen angewendet werden. Es kann auch zur Charakterisierung von Formmassen und Erzeugnissen aus PVC herangezogen werden, besonders hinsichtlich der Wirksamkeit ihrer Wärmestabilisierungssysteme. Es ist anwendbar auf gefärbte Formmassen und Produkte aus PVC, bei denen eine Verfärbungsprüfung unter Wärmeeinwirkung unbefriedigend sein kann.