Rubber and rubber products — Determination of the composition of vulcanizates and uncured compounds by thermogravimetry — Part 1: Butadiene, ethylene-propylene copolymer and terpolymer, isobutene-isoprene, isoprene and styrene-butadiene rubbers

ISO 9924-1:2016 specifies a thermogravimetric method for the determination of the total organic content, carbon black content and ash in vulcanizates and uncured compounds. The loss in mass at 300 °C is an approximate guide to the volatile-matter content of the compound. The method is suitable for the analysis of rubber compounds and vulcanizates containing the following rubbers occurring alone or as mixtures: a) polyisoprene of natural or synthetic origin; b) polybutadiene; c) styrene-butadiene copolymers; d) isobutylene-isoprene copolymers; e) ethylene-propylene copolymers and related terpolymers. NOTE The field of application of the method may be extended to the analysis of compounds containing rubbers different from those given in this subclause, provided that the applicability of the method is tested beforehand using known compounds or vulcanizates having a similar composition. Other compounds are covered in ISO 9924‑2. The method is not suitable for rubbers containing polymers which form a carbonaceous residue during pyrolysis, such as many chlorine- or nitrogen-containing rubbers. The method is also not suitable for materials containing additives which cause the formation of carbonaceous residues during pyrolysis, such as cobalt and lead salts or phenolic resins. The method is not suitable for compounds containing mineral fillers, such as carbonates or hydrated aluminium oxides, which decompose in the temperature range from 25 °C to 650 °C, unless suitable corrections based on prior knowledge of filler behaviour can be made. The method is not suitable for the determination of the total polymer content of compounds or vulcanizates containing non-rubber organic ingredients that cannot be completely removed by solvent extraction carried out in accordance with ISO 1407.

Caoutchouc et produits à base de caoutchouc — Détermination de la composition des vulcanisats et des mélanges non vulcanisés par thermogravimétrie — Partie 1: Caoutchoucs butadiène, copolymères et terpolymères éthylène-propylène, isobutène-isoprène, isoprène et butadiène-styrène

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Status
Published
Publication Date
17-Jul-2016
Current Stage
9092 - International Standard to be revised
Start Date
09-Nov-2021
Completion Date
09-Nov-2021
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INTERNATIONAL ISO
STANDARD 9924-1
Third edition
2016-08-01
Rubber and rubber products —
Determination of the composition of
vulcanizates and uncured compounds
by thermogravimetry —
Part 1:
Butadiene, ethylene-propylene
copolymer and terpolymer, isobutene-
isoprene, isoprene and styrene-
butadiene rubbers
Caoutchouc et produits à base de caoutchouc — Détermination de
la composition des vulcanisats et des mélanges non vulcanisés par
thermogravimétrie —
Partie 1: Caoutchoucs butadiène, copolymères et terpolymères
éthylène-propylène, isobutène-isoprène, isoprène et butadiène-styrène
Reference number
ISO 9924-1:2016(E)
ISO 2016
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ISO 9924-1:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland

All rights reserved. Unless otherwise specified, 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 on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

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copyright@iso.org
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ii © ISO 2016 – All rights reserved
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ISO 9924-1:2016(E)
Contents Page

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

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

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

3 Principle ........................................................................................................................................................................................................................ 2

4 Reagents ........................................................................................................................................................................................................................ 2

5 Apparatus ..................................................................................................................................................................................................................... 2

6 Thermogravimetric analyser checks ............................................................................................................................................... 3

7 Procedure..................................................................................................................................................................................................................... 5

8 Expression of results ........................................................................................................................................................................................ 6

9 Precision ....................................................................................................................................................................................................................... 7

10 Test report ................................................................................................................................................................................................................... 7

Annex A (informative) Precision ............................................................................................................................................................................... 8

Bibliography ................................................................................................................................................................................................................................ 9

© ISO 2016 – All rights reserved iii
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ISO 9924-1:2016(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 ISO/TC 45, Rubber and rubber products, SC 2, Testing

and analysis.

This third edition cancels and replaces the second edition (ISO 9924-1:2000), of which it constitutes a

minor revision with the following changes:
— precision clause moved to Annex A;
— NBR-related descriptions removed from Clause 9.

ISO 9924 consists of the following parts, under the general title Rubber and rubber products —

Determination of the composition of vulcanizates and uncured compounds by thermogravimetry:

— Part 1: Butadiene, ethylene-propylene copolymer and terpolymer, isobutene-isoprene, isoprene and

styrene-butadiene rubbers
— Part 2: Acrylonitrile-butadiene and halobutyl rubbers

— Part 3: Hydrocarbon rubbers, halogenated rubbers and polysiloxane rubbers after extraction

iv © ISO 2016 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 9924-1:2016(E)
Rubber and rubber products — Determination of the
composition of vulcanizates and uncured compounds by
thermogravimetry —
Part 1:
Butadiene, ethylene-propylene copolymer and
terpolymer, isobutene-isoprene, isoprene and styrene-
butadiene rubbers

WARNING — Persons using this part of ISO 9924 should be familiar with normal laboratory

practice. This part of ISO 9924 does not purport to address all of the safety problems, if any,

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

health practices and to ensure compliance with any national regulatory conditions.

1 Scope

1.1 This part of ISO 9924 specifies a thermogravimetric method for the determination of the total

organic content, carbon black content and ash in vulcanizates and uncured compounds. The loss in mass

at 300 °C is an approximate guide to the volatile-matter content of the compound.

1.2 The method is suitable for the analysis of rubber compounds and vulcanizates containing the

following rubbers occurring alone or as mixtures:
a) polyisoprene of natural or synthetic origin;
b) polybutadiene;
c) styrene-butadiene copolymers;
d) isobutylene-isoprene copolymers;
e) ethylene-propylene copolymers and related terpolymers.

NOTE The field of application of the method may be extended to the analysis of compounds containing

rubbers different from those given in this subclause, provided that the applicability of the method is tested

beforehand using known compounds or vulcanizates having a similar composition. Other compounds are covered

in ISO 9924-2.

1.3 The method is not suitable for rubbers containing polymers which form a carbonaceous residue

during pyrolysis, such as many chlorine- or nitrogen-containing rubbers.

1.4 The method is also not suitable for materials containing additives which cause the formation of

carbonaceous residues during pyrolysis, such as cobalt and lead salts or phenolic resins.

1.5 The method is not suitable for compounds containing mineral fillers, such as carbonates or

hydrated aluminium oxides, which decompose in the temperature range from 25 °C to 650 °C, unless

suitable corrections based on prior knowledge of filler behaviour can be made.
© ISO 2016 – All rights reserved 1
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ISO 9924-1:2016(E)

1.6 The method is not suitable for the determination of the total polymer content of compounds or

vulcanizates containing non-rubber organic ingredients that cannot be completely removed by solvent

extraction carried out in accordance with ISO 1407.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

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

ISO 1407, Rubber — Determination of solvent extract
3 Principle

3.1 A weighed test portion is heated, following a pre-set programme, from 70 °C to 300 °C in a stream

of nitrogen and is maintained at 300 °C for 10 min. The loss in mass indicates, approximately, the total

content of non-rubber organic matter volatile at 300 °C. In general, this value is not equivalent to the

value of the solvent extract.

3.2 The oven temperature is then raised to 550 °C, still in a stream of nitrogen, and maintained at

550 °C for 15 min. The organic matter which was undistilled at 300 °C and the polymer distill off, and the

loss in mass between 70 °C and 550 °C represents the total organic matter content.

NOTE The total rubber content is calculated by subtracting the value of the solvent extract, determined

in accordance with ISO 1407, from the total organic content, provided that all non-rubber ingredients can be

extracted.

3.3 The oven temperature is raised from 550 °C to 650 °C in a stream of nitrogen, then the gas is

changed from nitrogen to air or oxygen, or a mixture of air or oxygen, and the temperature is maintained

at 650 °C for 15 min or until no further loss in mass is observed. The carbon black is burnt off, and the

loss in mass in the oxidizing atmosphere at 650 °C, thus represents the carbon black content. A balanced

flow of gas is maintained throughout the changeover to avoid buoyancy effects.
3.4 The mass of the residue at 650 °C represents the ash.
4 Reagents
4.1 Dry nitrogen, with an oxygen content of less than 10 mg/kg (ppm).
4.2 Dry air or oxygen.
5 Apparatus
5.1 Thermogravimetric analyser.

There are many types of analyser commercially available. All should be suitable for use with this part of

ISO 9924, but their suitability should be checked using the procedure in Clause 6. Calibrate and operate

the thermogravimetric analyser in accordance with the manufacturer’s instructions.

The basic components of an analyser are as follows.
5.1.1 Thermogravimetric balance.
5.1.2 Electrically heated, thermo-regulated oven.
2 © ISO 2016 – All rights reserved
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ISO 9924-1:2016(E)
5.1.3 Temperature programmer, for the oven.

5.1.4 Switching device, allowing a stream of nitrogen or a stream of air or oxygen (or a mixture of

nitrogen and air or oxygen) to flow through the oven at a predetermined and constant flow rate.

5.1.5 X/Y recorder, for recording the temperature/mass plot. Alternatively, temperature/time and

mass/time plots may be recorded simultaneously using a two-pen Y/T recorder.

5.1.6 Auxiliary equipment for producing differential curves (useful but not mandatory for this

part of ISO 9924).
5.2 Analytical balance, capable of weighing to 0,1 mg.
6 Thermogravimetric analyser checks
6.1 Measurement of purge time, t

6.1.1 Place a test portion of carbon black or black-filled rubber, as specified in the manufacturer’s

instructions, in the thermobalance sample pan and heat to 650 °C in a stream of nitrogen, at the maximum

rate allowed by the temperature programmer.

6.1.2 Maintaining the temperature at 650 °C, introduce air or oxygen and allow the test portion to

combust fully.

6.1.3 When there is no further mass change, switch off the oven heater and allow the oven to cool to

room temperature, maintaining the air or oxygen flow. At this point, the oven will have been thoroughly

purged with air or oxygen. The following oper
...

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