ISO/PWI 25991

Plastics-- Ethylene vinyl alcohol (EVOH) copolymer — Determination of ethylene content

Scope

This document specifies two categories of methods for the determination of the ethylene content of ethylene vinyl alcohol (EVOH) copolymers, for use in the designation of such copolymers according to ISO 21309-1. One category is referred to as “reference method”, the other as “test methods”.
The “reference methods” are used to calibrate the method used for the determination of the ethylene content of EVOH copolymers.
The “test methods” are other methods which can be used for the determination if they are calibrated using the reference methods described in Clause 4, provided they show a certain permissible repeatability.
This document is applicable to copolymers of ethylene and vinyl alcohol containing from 15 mol % to 60 mol % of ethylene. It applies to materials ready for normal use in the form of powder, granules or pellets, unmodified or modified by colorants, additives, fillers, etc.
This document is not applicable to mixtures of EVOH with other polymers or fillers.