ISO 9924-1:2023
(Main)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
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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INTERNATIONAL ISO
STANDARD 9924-1
Fourth edition
2023-03
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 2023
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Thermogravimetric analyser checks . 3
7.1 Measurement of purge time, t . 3
p
7.2 Discrimination between carbon black and calcium carbonate . 4
8 Procedure .5
8.1 Preliminary operations . 5
8.2 Test procedure . 5
9 Expression of results . 6
9.1 For instruments indicating the mass in milligrams . . 6
9.2 For instruments adjustable to give an initial reading of 100 % . 7
9.3 Total polymer content . 7
10 Precision . 7
11 Test report . 7
Annex A (informative) Precision . 8
Bibliography .10
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, 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
www.iso.org/iso/foreword.html.
This document was prepared by ISO/TC 45, Rubber and rubber products, SC 2, Testing and analysis.
This fourth edition cancels and replaces the third edition (ISO 9924-1:2016), which has been technically
revised:
The main changes are as follows:
— Clause 3 is added;
— Added "If graphite is present” (see 4.3, 4.4). to make the document more comprehensive;
— Modified the steps of heating rate (see 8.2.5 and 8.2.7) to make the decomposition process of the
sample more uniform;
— Modified the carbon black content part (see 9.2.3). The modified expression is more reasonable and
consistent with the "test procedure" clause;
— Modified the variables of formulae (see 9.1 and 9.3) to be written using symbols instead of text.
A list of all parts in the ISO 9924 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
INTERNATIONAL STANDARD ISO 9924-1:2023(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 document should be familiar with normal laboratory practice.
This document 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
be informed of any national regulatory conditions.
1 Scope
This document 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 blowing agents and mineral fillers, such as
carbonates, hydrated aluminium oxides, hydrated silicon oxides or silicates 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.
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 1407, Rubber — Determination of solvent extract
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
4.1 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.
4.2 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
according to ISO 1407, from the total organic content, provided that all non-rubber ingredients can be extracted.
4.3 Reduce the oven temperature to 300 °C in a stream of nitrogen, then the gas is changed from
nitrogen to air or oxygen, or a mixture of air or oxygen. Then, raise the oven temperature to 650 °C and
maintain at this temperature 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. If graphite is present at 850 °C, a balanced flow of gas is maintained throughout the changeover
to avoid buoyancy effects.
4.4 The mass of the residue at 650 °C represents the ash (if graphite is present, at 850 °C).
5 Reagents
5.1 Dry nitrogen, with an oxygen content of less than 10 mg/kg (ppm).
5.2 Dry air or oxygen.
6 Apparatus
6.1 Thermogravimetric analyser. There are many types of analysers commercially available.
All should be suitable for use with this document, but their suitability should be checked using the
procedure in Clause 7. Calibrate and operate the thermogravimetric analyser in accordance with the
manufacturer’s instructions.
The basic components of an analyser are as follows.
6.1.1 Thermogravimetric balance.
6.1.2 Thermo-regulated oven, electrically heated.
6.1.3 Temperature programmer, for the oven.
6.1.4 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.
6.1.5 X/Y recorder, for recording the temperature/mass plot. Alternatively, temperature/time and
mass/time plots may be recorded si
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