ISO 14558:2000

INTERNATIONAL ISO
STANDARD 14558
First edition
2000-08-15
Rubber — Determination of residual
unsaturation of hydrogenated nitrile rubber
(HNBR) by infrared spectroscopy
Caoutchouc — Détermination de la non-saturation résiduelle du caoutchouc
nitrile hydrogéné (HNBR) par spectroscopie à infrarouge
Reference number
ISO 14558:2000(E)
© ISO 2000

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ISO 14558:2000(E)
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ISO 14558:2000(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
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(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 14558 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 2, Testing and analyses.
Annex A of this International Standard is for information only.
©
ISO 2000 – All rights reserved iii

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INTERNATIONAL STANDARD ISO 14558:2000(E)
Rubber — Determination of residual unsaturation of hydrogenated
nitrile rubber (HNBR) by infrared spectroscopy
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 a method for determining the residual unsaturation in hydrogenated nitrile rub-
ber (HNBR) by measuring the infrared (IR) absorbance of HNBR films cast from solution.
This standard assumes that samples and IR spectra are prepared and analysed by experienced personnel and that
equipment is operated in accordance with the manufacturer's instructions. Details for operating an IR spectrometer
are not included in this method.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do not
apply. However, parties to agreements based on this International Standard are encouraged to investigate the possi-
bility of applying the most recent edition of the normative document indicated below. For undated references, the lat-
est edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently
valid International Standards.
1)
ISO 1795:— , Rubber, raw natural and raw synthetic — Sampling and further preparative procedures.
3 Principle
Raw, unvulcanized HNBR is purified by precipitation with methanol from a solution in methyl ethyl ketone (MEK) or by
extraction of the solid HNBR with methanol in a Soxhlet apparatus.
The purified sample is dissolved in MEK and a film is cast on a potassium bromide (KBr) disc.
The IR spectrum of the film is obtained with a Fourier-transform (FT) or dispersive IR spectrometer.
The “corrected absorbance” of the specific absorbance bands for acrylonitrile (AN), butadiene (BD) and hydrogen-
ated butadiene (HBD) are determined using the baseline method and the percentage of residual unsaturation
(double bonds in unhydrogenated butadiene) is calculated with the aid of absorbance factors from the literature
(see 8.5).
1) To be published. (Revision of ISO 1795:1992)
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ISO 14558:2000(E)
4Reagents
Reagent grade chemicals should preferably be used in all determinations. Other grades may be used provided they
are of sufficiently high purity not to lessen the accuracy of the determination.
4.1 Methyl ethyl ketone (MEK).
4.2 Methanol.
4.3 Dry, compressed nitrogen.
4.4 Potassium bromide discs.
5 Sampling
Sample the raw rubber in accordance with ISO 1795.
6 Apparatus
3
6.1 Conical flask, 50 cm , with ground-glass stopper.
6.2 Flask shaker.
3
6.3 Beaker,.250 cm
6.4 Magnetic stirrer.
3
6.5 Soxhlet extraction apparatus,with 150 cm flask.
6.6 Extraction thimbles,.27 mm� 100 mm
�
6.7 Koffler heating bench, or other heating device, with temperature control to� 2 C.
−1
6.8 Fourier-transform IR (FTIR) spectrometer, with2cm resolution or a dispersive IR spectrometer capable of
equivalent spectral resolution. The instrument shall be capable of scale expansion along the absorbance or trans-
−1 −1
mittance axis over the special region of 2 500 cm to 600 cm .
7 Procedure
7.1 Sample preparation
7.1.1 Purification by precipitation
3 3
7.1.1.1 Transfer 1 g of t
...