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 as PVC) which undergo
dehydrochlorination (the evolution of hydrogen chloride).
1.2 The method may be used as a quality control
test during manufacture and conversion of PVC compounds.
lt may also be used for the characterization
of PVC compounds and products, especially with regard
to the effectiveness of their heat-stabilizing systems.
lt is suitable for coloured PVC compounds and products
for which 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 tan 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 products, originating from the decomposition
of certain comonomers (such as Vinyl esters of organic
acids) or of plasticizers, stabilizers and other
additives, may effect the pH or the conductivity of an
aqueous Solution when they are absorbed. Consequently,
the results obtained for different products by
the methods described in Parts 2 and 3 of ISO 182
may not be comparable with those obtained using the
method described in the present part of ISO 182.
1.5 This part of ISO 182 specifies a potentiometric
method for the determination of chloride ion (Cl-)
concentration (expressed as pCI) in an absorbing solution,
independent of the presence of other ions. The
value pCl is defined as - Ig ccI, where ccI is (...abbreviated)
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.