FprEN ISO 8985

Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content (ISO/FDIS 8985:2021)

Kunststoffe - Ethylen-Vinylacetat-Copolymer (EVAC)-Thermoplasten - Bestimmung des Vinylacetatgehalts (ISO/FDIS 8985:2021)

Dieses Dokument legt zwei Kategorien von Verfahren zur Bestimmung des Vinylacetatgehalts (VAC, en: vinyl acetate content) von Ethylen-Vinylacetat-Copolymeren (EVAC) auf der Grundlage ihrer Bezeichnung nach ISO 21301 1ss fest. Dabei bezeichnet eine Kategorie die „Referenzverfahren“ und die andere die „Prüfverfahren“.
Die „Referenzverfahren“ werden angewendet, um das zur Bestimmung des Vinylacetatgehalts von Ethylen-Vinylacetat-Copolymeren angewendete Verfahren zu kalibrieren.
Die „Prüfverfahren“ stellen weitere Verfahren dar, die für die Bestimmung angewendet werden können, wenn sie unter Anwendung eines der in Abschnitt 4 beschriebenen Referenzverfahren kalibriert wurden und wenn sie eine bestimmte zulässige Wiederholpräzision aufweisen.

Plastiques - Copolymères éthylène/acétate de vinyle (EVAC) thermoplastiques - Dosage de l'acétate de vinyle (ISO/FDIS 8985:2021)

Polimerni materiali - Termoplastični kopolimer etilena in vinil acetata (EVAC-kopolimer) - Ugotavljanje deleža vinil acetata (ISO/DIS 8985:2020)

General Information

• Status: Not Published
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: CEN/TC 249 - Plastics
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Due Date: 25-Dec-2021
• Completion Date: 25-Dec-2021
• Ref Project: kSIST FprEN ISO 8985:2020 - Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content (ISO/DIS 8985:2020)

RELATIONS

• Revised: EN ISO 8985:1998 - Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of vinyl acetate content (ISO 8985:1998)
• Effective Date: 21-Jan-2020

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 8985:2020
01-september-2020
Polimerni materiali - Termoplastični kopolimer etilena in vinil acetata (EVAC-
kopolimer) - Ugotavljanje deleža vinil acetata (ISO/DIS 8985:2020)

Plastics - Ethylene/vinyl acetate copolymer (EVAC) thermoplastics - Determination of

vinyl acetate content (ISO/DIS 8985:2020)

Kunststoffe - Ethylen-Vinylacetat-Copolymer (EVAC)-Thermoplasten - Bestimmung des

Vinylacetatgehalts (ISO/DIS 8985:2020)

Plastiques - Copolymères éthylène/acétate de vinyle (EVAC) thermoplastiques - Dosage

de l'acétate de vinyle (ISO/DIS 8985:2020)
Ta slovenski standard je istoveten z: prEN ISO 8985
ICS:
83.080.20 Plastomeri Thermoplastic materials
oSIST prEN ISO 8985:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 8985:2020
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oSIST prEN ISO 8985:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8985
ISO/TC 61/SC 9 Secretariat: KATS
Voting begins on: Voting terminates on:
2020-06-29 2020-09-21
Plastics — Ethylene/vinyl acetate copolymer (EVAC)
thermoplastics — Determination of vinyl acetate content

Plastiques — Copolymères éthylène/acétate de vinyle (EVAC) thermoplastiques — Dosage de l'acétate

de vinyle
ICS: 83.080.20
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 8985:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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oSIST prEN ISO 8985:2020
ISO/DIS 8985:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

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ii © ISO 2020 – All rights reserved
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oSIST prEN ISO 8985:2020
ISO/DIS 8985:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Reference methods ............................................................................................................................................................................................ 2

4.1 Reference method 1: Hydrolysis and back titration ............................................................................................... 2

4.1.1 Principle .................................................................................................................................................................................. 2

4.1.2 Reagents .................................................................................................................................................................................. 2

4.1.3 Apparatus ............................................................................................................................................................................... 2

4.1.4 Procedure ............................................................................................................................................................................... 3

4.1.5 Expression of results .................................................................................................................................................... 3

4.1.6 Test report ............................................................................................................................................................................. 4

4.2 Reference method 2: Saponification and potentiometric titration ............................................................ 4

4.2.1 Principle .................................................................................................................................................................................. 4

4.2.2 Reagents .................................................................................................................................................................................. 4

4.2.3 Apparatus ............................................................................................................................................................................... 4

4.2.4 Procedure ............................................................................................................................................................................... 5

4.2.5 Expression of results .................................................................................................................................................... 6

4.2.6 Test report ............................................................................................................................................................................. 6

4.3 Reference method 3: Measurement of oxygen ............................................................................................................ 6

4.3.1 Principle .................................................................................................................................................................................. 6

4.3.2 Apparatus ............................................................................................................................................................................... 6

4.3.3 Sampling...............................................................................................................................................................................10

4.3.4 Calibration ..........................................................................................................................................................................10

4.3.5 Calculation of vinyl acetate content .............................................................................................................11

4.3.6 Test report ..........................................................................................................................................................................11

5 Examples of test methods.........................................................................................................................................................................11

5.1 Method using infrared spectrometry ...............................................................................................................................11

5.1.1 Principle ...............................................................................................................................................................................11

5.1.2 Apparatus and materials ........................................................................................................................................11

5.1.3 Procedure ............................................................................................................................................................................12

5.1.4 Expression of results .................................................................................................................................................14

5.1.5 Test ............................................................................................................................................................................................15

5.1.6 Principle ...............................................................................................................................................................................15

5.1.7 Reagents and materials ...........................................................................................................................................15

5.1.8 Apparatus ............................................................................................................................................................................15

5.1.9 Procedure ............................................................................................................................................................................16

5.1.10 Expression of results .................................................................................................................................................17

5.1.11 Test report ..........................................................................................................................................................................17

5.2 Iodometric method...........................................................................................................................................................................17

5.2.1 Principle ...............................................................................................................................................................................17

5.2.2 Reagents ...............................................................................................................................................................................17

5.2.3 Apparatus ............................................................................................................................................................................18

5.2.4 Procedure ............................................................................................................................................................................18

5.2.5 Expression of results .................................................................................................................................................18

5.2.6 Test report ..........................................................................................................................................................................19

5.3 Themogravimetry method .........................................................................................................................................................19

5.3.1 Principle ...............................................................................................................................................................................19

5.3.2 Apparatus ............................................................................................................................................................................19

5.3.3 Test specimens................................................................................................................................................................19

5.3.4 Calibration ..........................................................................................................................................................................19

5.3.5 Procedure ............................................................................................................................................................................19

5.3.6 Test report ..........................................................................................................................................................................21

© ISO 2020 – All rights reserved iii
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oSIST prEN ISO 8985:2020
ISO/DIS 8985:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,

as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the

Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .htmL.

The committee responsible for this document is Technical Committee ISO/TC 61, Plastics, Subcommittee

SC 9, Thermoplastic materials.

This third edition cancels and it replaces the second edition( ISO 8985:1998(E)).which has been

technically revised by adding a “themogravimetry test method” and modifying the method of infrared

spectrum.

Any feedback or questions on this document should the directed to the user’s national standards body.

A complete listing of these bodies can be found at www .iso .org/ members .htmL.
iv © ISO 2020 – All rights reserved
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oSIST prEN ISO 8985:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 8985:2020(E)
Plastics — Ethylene/vinyl acetate copolymer (EVAC)
thermoplastics — Determination of vinyl acetate content

SAFETY PRECAUTIONS — Persons using this document should be familiar with normal laboratory

practice, if applicable. This document does not purport to address all of the safety concerns, if

any, associated with its use. It is the responsibility of the user to establish appropriate safety

and health practices.
1 Scope

This international standard specifies two categories of method for the determination of the vinyl

acetate (VAC) content of Ethylene/vinyl acetate (EVAC) copolymer, for use in the designation of such

copolymers in accordance with ISO 21301-1:2019.One category is referred to as “reference methods”,

the other as “test methods”.

The “reference methods” are used to calibrate the method used for the determination of the vinyl

acetate content of ethylene/vinyl acetate copolymers.

The "test methods" are other methods which can be used for the determination if they are calibrated

using one of the reference methods described in clause 4 provided they show a certain permissible

repeatability.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 21301-1, Plastics — Ethylene-vinyl acetate (EVAC) moulding and extrusion materials — Part 1:

Designation system and basis for specifications
ISO 472, Plastics — Vocabulary
ISO 4799, Laboratory glassware — Condensers

ISO 11358-1, Plastics — Thermogravimetry (TG) of polymers — Part 1: General principles

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 472 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
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oSIST prEN ISO 8985:2020
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4 Reference methods
4.1 Reference method 1: Hydrolysis and back titration
4.1.1 Principle

A test portion is dissolved in xylene and the acetate groups are hydrolysed with alcoholic potassium

hydroxide solution. An excess of sulfuric or hydrochloric acid is added. The acid is back titrated with a

standard sodium hydroxide solution in the presence of phenophthalein as indicator.

4.1.2 Reagents

During the analysis, use only reagents of recognized analytical quality and distilled water or water of

equivalent purity.
4.1.2.1 Xylene.

4.1.2.2 Sulfuric acid, approx. 5g/l solution, or hydrochoric acid, approx. 3,7g/l solution.

4.1.2.3 Potassium hydroxide, approx. 5,6g/l ethanol solution.

Dissolve 5,6g of solid potassium hydroxide (KOH) in 500ml of ethanol, make up to 1000ml, leave to

settle until the next day and decant the clear part of the solution.
4.1.2.4 Sodium hydroxide, standard solution, c(NaOH) = 0,1 mol/l.
4.1.2.5 Phenolphthalein, indicator solution.
Dissolve 0,7g of phenolphthalein in 100ml of ethanol
4.1.3 Apparatus
Standard laboratory apparatus, plus the following:
4.1.3.1 Burette, 50ml capacity, for the sodium hydroxide solution (4.1.2.4).
4.1.3.2 Pipette, 30ml capacity, for the acid solution (4.1.2.2).
4.1.3.3 Pipette, 25ml capacity, for the potassium hydroxide solution (4.1.2.3).
4.1.3.4 Test tube, 50ml capacity, for the xylene (4.1.2.1).
4.1.3.5 Flask, up to 300ml capacity, with stopper.
4.1.3.6 Dropping bottle, for the phenolphthalein indicator solution (4.1.2.5).
4.1.3.7 Reflux condenser, at least 500ml long, in accordance with ISO 4799.

4.1.3.8 Heating equipment, sand bath, oil bath or heating jacket, adjustable to 200°C.

4.1.3.9 Analytical balance, with an accuracy of 0,1mg.
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4.1.4 Procedure
4.1.4.1 Determination

4.1.4.1.1 Weigh a quantity of dry polymer as shown in Table 1 into the flask (4.1.3.5) to the nearest

0,1mg. The mass of each sample particle shall be less than approx. 0,05g.
Table 1 — Guide to the mass of the sample to be used
Assumed vinyl acetate Approximate mass of test
content, w(VAC) portion
% g
w(VAC)≤10 1
10< w(VAC) ≤20 0,5
20< w(VAC) ≤40 0,3
40< w(VAC) 0,2

When analysing an unknown sample, first carry out a preliminary test under conditions which are

valid for a copolymer containing 20% to 40% VAC.

4.1.4.1.2 Add 50ml of xylene (4.1.2.1) to the contents of the flask and 25ml of potassium hydroxide

(4.1.2.3), using the pipette (4.1.3.3). Heat the flask, topped with the reflux condenser (4.1.3.7), for 2 hours

using the heating apparatus. After hydrolysis, remove the flask from the heating apparatus and allow

to cool to ambient temperature. Add 30mL of sulfuric or hydrochloric acid (4.1.2.2), using the pipette

(4.1.3.2), stopper the flask and shake vigorously. Add several drops of phenolphthalein solution (4.1.2.5)

and titrate the excess acid with standard sodium hydroxide solution (4.1.2.4), shaking the flask during

the titration.
4.1.4.2 Blank test

Carry out a blank test in parallel with the determination, following the same procedure and using the

same reagents but omitting the test portion.
4.1.5 Expression of results

4.1.5.1 The vinyl acetate content w(VAC), expressed as a percentage by mass, is given by the formula:

8,609×−vv ×c
12 1
wV()AC = (1)
where

v is the volume, in millilitres, of sodium hydroxide solution used for the determination;

v is the volume, in millilitres, of sodium hydroxide solution used for the blank test;

c is the actual concentration, expressed in moles per litre , of the sodium hydroxide solution used

for the titration;
m is the mass, in grams, of the test portion (see 4.1.4.1.1).

4.1.5.2 Carry out two determinations. If the results differ by more than 1%, discard them and run the

determinations again. Report the arithmetic mean of the two determinations.
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oSIST prEN ISO 8985:2020
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4.1.6 Test report
The test report shall contain the following information:
a) a reference to this International Standard and the method used;
b) all details necessary for the complete identification of the sample;
c) the result, expressed in accordance with 4.1.5.2.
4.2 Reference method 2: Saponification and potentiometric titration
4.2.1 Principle

A test portion is dissolved in a mixture of xylene and hexan-1-ol and the acetate groups are hydrolysed

with alcoholic potassium hydroxide solution. Acetone is added to prevent copolymer precipitation. The

excess alkali is titrated with standard hydrochloric acid using a potentiometric titrimeter.

4.2.2 Reagents

During analysis use only reagents of recognized analytical quality and distilled water or water of

equivalent purity.
4.2.2.1 Xylene.
4.2.2.2 Hexan-1-ol.
4.2.2.3 Potassium hydroxide, approx. 28g/l ethanolic solution.
4.2.2.4 Acetone.
4.2.2.5 Hydrochloric acid, standard solution, c(HCl) = 0,3mol/l.
4.2.2.6 Lithium chloride, 40g/l ethanolic solution.
4.2.3 Apparatus
Standard laboratory equipment, plus the following:

4.2.3.1 Potentiometric titrator, with a 10ml capacity burette graduated every 0,02ml, a millivoltmeter

or other suitable type of voltmeter, a glass measurement electrode, a silver/silver chloride reference

electrode and a connecting bridge and beaker filled with an ethanolic solution of lithium chloride

(4.2.2.6). Other types of potentiometric titrator may be used.

4.2.3.2 Test tube, capacity 50ml, for the xylene (4.2.2.1) and the acetone (4.2.2.4).

4.2.3.3 Burette, capacity 5ml, for the potassium hydroxide solution (4.2.2.3).
4.2.3.4 Pipette, capacity 10ml, for the hexan-1-ol (4.2.2.2).
4.2.3.5 Flask, capacity 100ml.
4.2.3.6 Reflux condenser, at least 300mm long, in accordance with ISO 4799.

4.2.3.7 Heating apparatus; sand bath, oil bath or heating jacket, adjustable to approx. 200°C.

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oSIST prEN ISO 8985:2020
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4.2.3.8 Analytical balance, with an accuracy of 0,1mg.
4.2.3.9 Magnetic stirrer.
4.2.4 Procedure
4.2.4.1 Determination

Weigh a quantity of dry polymer as shown in Table 2 into the flask to the nearest 0,1mg. The mass of

each sample particle shall be less than approx. 0,05g.
Table 2 — Guide to the mass of sample to be used
Assumed vinyl acetate content, Approxinate mass of test
w(VAC) portion
% g
w(VAC)≤2 1
2< w(VAC) ≤5 0,5
5< w(VAC) ≤30 0,2
30< w(VAC) 0,1

When analysing an unknown sample, first of all carry out a preliminary test under conditions which

are valid for a copolymer containing 5% to 30% vinyl acetate.

4.2.4.1.1 Add 25ml of xylene (4.2.2.1) to the contents of the flask and 10ml of hexan-1-ol (4.2.2.2)

and5ml of potassium hydroxide solution (4.2.2.3). Heat the flask, topped with the reflux condenser

(4.2.3.6), for 30 min., using the heating apparatus (4.2.2.7) set at boiling temperature. After 30 min.,

remove the flask from the heating apparatus and allow to cool for 5-6 min., then introduce 35ml of

acetone (4.2.2.4) through the top of the condenser. Remove the condenser and place the flask (if conical)

on the magnetic stirrer (4.2.2.9), otherwise transfer the solution to a beaker first. Immerse the glass

electrode (see 4.2.3.1) and one of the ends of the connecting bridge into the flask or beaker. Immerse the

other end of the connecting bridge and the silver/silver chloride reference electrode (see 4.2.3.1) in the

beaker filled with the ethanolic solution of lithium chloride (4.2.2.6).

Carry out the potentiometric titration immediately, adding standard hydrochloric acid (4.2.2.5) until

the first drop in potential and stirring all the time. When close to the end point, add acid in 0,04ml to

0,06ml increments.

When the end point is reached, read off the voltage, in millivolts, on the titrator as well as the volume of

hydrochloric acid added.

The end point of the titration is that point at which the greatest variation in potential occurs for a given

increment of acid added. In the event of two such points occurring, take the first value as the end point.

The end point may also be determined graphically.
4.2.4.2 Blank test

Carry out a blank test in parallel with the determination, following the same procedure and using the

same reagents but omitting the test portion. Plot the titration curve. The mean value of the peak on the

titration curve is taken as the end point.
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oSIST prEN ISO 8985:2020
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4.2.5 Expression of results

4.2.5.1 The vinyl acetate content w(VAC), expressed as a percentage by mass, is given by the formula:

8,609×−vv ×c
34 2
wV()AC = (2)
where

v is the volume, in millilitres, of standard hydrochloric acid used for the blank test;

is the volume; in millilitres, of standard hydrochloric acid solution used for the determination;

c is the actual concentration, in moles per litre, of the standard hydrochloric acid solution used

for the titration;
m is the mass, in grams, of the test portion (see 4.2.4.1.1).

4.2.5.2 Carry out two determinations. If the results differ by more than 1%, discard them and run the

determination again. Report the arithmetic mean of the two determinations.
4.2.6 Test report
The test report shall contain the following information:
a) a reference to this International Standard and the method used;
b) all details necessary for complete identification of the sample;
c) the result, expressed in accordance with 4.2.5.2.
4.3 Reference method 3: Measurement of oxygen
4.3.1 Principle

The determination of the oxygen content is carried out using one of the traditional methods of

elementary organic analysis. Therefore the following 3 methods as shown Table 3 are applied.

Table 3 — Traditional methods of elementary organic analysis
Method Reaction Detection Test sample Measurement Detection Absolute
method range dispersion
% %
4.3.3.1 Pyrolysis and Coulometry Micro Absolute 0,2 (0,02)
reoxidation
4.3.3.2 Pyrolysis Infrared Micro Comparative 0,03 10 relative
absorption
4.3.3.3 Pyrolysis and Gravimetric Micro Absolute 0,05 0,05
reoxidation analysis
4.3.2 Apparatus

Any apparatus (commercial or otherwise) may be used, provided it meets the following requirements:

Detection range: 0,2%
Dispersion: 0,2% absolute or 10% relative if O < 1%
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oSIST prEN ISO 8985:2020
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4.3.2.1 Determination by acidimetric coulometry
4.3.2.1.1 Principle

The oxygen is transformed into carbon monoxide by pyrolysis at 1070°C, in a helium or nitrogen

atmosphere, of a micro-analytical sample and passing the pyrolysis gases through an oven lined with

amorphous carbon heated to 1120°C.

Any acid components are absorbed by a mixture of soda lime and magnesium perchlorate. The carbon

monoxide is then passed over CuO at 250°C where it is oxidized to carbon dioxide which is determined

by coulometry.
4.3.2.1.2 Coulometric measurement of the carbon dioxide

The carbon dioxide is absorbed by the cathodic part of a coulometric cell, containing an approx. 5%

(m/V) solution of barium perchlorate, in accordance with the following formula:
++ +
CO + H O + Ba → BaCO + 2 H
2 2 3

The H+ ions are neutralized by adding OH- ions, which are produced electrolytically by the coulometer,

in accordance with the following formula:
− −
2H O + 2 e → H + 2O H
2 2

The electricity supply from the coulometer is controlled by a silver/silver chloride and a glass electrode

which detect the variations in the pH of the solution, and the quantity of carbon dioxide is calculated

from the quantity of electricity suppl
...