ISO 15671:2000

INTERNATIONAL ISO
STANDARD 15671
First edition
2000-07-15
Rubber and rubber additives —
Determination of total sulfur content using
an automatic analyser
Caoutchouc et additifs pour caoutchouc — Dosage du soufre total à l'aide
d'un analyseur automatique
Reference number
ISO 15671:2000(E)
© ISO 2000

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ISO 15671:2000(E)
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ISO 15671:2000(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 com-
mittees. 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 liai-
son with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 15671 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 2, Testing and analyses.
©
ISO 2000 – All rights reserved iii

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INTERNATIONAL STANDARD ISO 15671:2000(E)
Rubber and rubber additives — Determination of total sulfur
content using an automatic analyser
WARNING — Persons using this International Standard should be familiar with normal laboratory practice.
This standard 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
This International Standard specifies an instrumental (automatic analyser) method for the determination of total sul-
fur in rubber and rubber additives.
2 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
2.1
sample
unit selected to represent the material to be analysed
2.2
test portion
actual material used in the analysis
2.3
control sample
material with a recognized content of sulfur, analysed with each set of test portions
3 Principle
3.1 Specified is a reliable, rapid, instrumental (automatic analyser) method for determining total sulfur in rubber and
rubber additives. The sulfur is determined by a single instrumental procedure consisting of weighing a test portion,
placing it in the instrument and initiating the (subsequently automatic) analytical process. The analysis may be con-
trolled manually to a limited degree, and a capability to perform computations automatically may be provided by the
instrument used to perform the analysis.
3.2 The actual process can vary substantially from instrument to instrument because a variety of means can be
used to meet the primary requirements of the method. The method includes the following:
a) conversion of sulfur-containing materials to sulfur dioxide in an oxygen stream;
b) determination of the sulfur dioxide by one of three detection schemes, and hence the total sulfur content.
3.3 In the hydrogen peroxide detection configuration, the sulfur dioxide is absorbed in hydrogen peroxide, con-
verting sulfur dioxide to sulfuric acid which is subsequently titrated with standard alkali, enabling the sulfur to be cal-
culated.
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ISO 15671:2000(E)
3.4 In the iodine solution detection configuration, the sulfur dioxide is absorbed in standard iodine solution, re-
ducing iodine to iodide which is subsequently measured by a polarized dual platinum electrode system, enabling the
sulfur to be calculated.
3.5 In the sulfur dioxide detection configuration, the sulfur dioxide is passed through an infrared absorption de-
tector and determined using a sulfur dioxide standard, enabling the sulfur to be calculated.
4 Requirements for apparatus
4.1 Because a variety of instrumental (automatic analyser) component configurations can be used satisfactorily for
this method, no specifications are presented with regard to overall system design. Functionally, however, the follow-
ing requirements are specified for all instruments.
4.2 The conditions for combustion of the sample shall be such that (for the full range of applicable samples) sulfur-
containing components shall be converted completely to sulfur dioxide. General instrumental conditions that affect
complete combustion include:
a) availability of the oxidant,
b) temperature,
c) time.
4.3 For the configuratio
...