ISO 21461:2009
(Main)Rubber — Determination of the aromaticity of oil in vulcanized rubber compounds
Rubber — Determination of the aromaticity of oil in vulcanized rubber compounds
ISO 21461:2009 provides a method for the selective determination of polyaromaticity of oil in vulcanized rubber compounds. The method is based on nuclear magnetic resonance (NMR) spectrometry.
Caoutchouc — Détermination de l'aromaticité des huiles dans les mélanges vulcanisés
General Information
Relations
Buy Standard
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21461
Second edition
2009-03-01
Rubber — Determination of the
aromaticity of oil in vulcanized rubber
compounds
Caoutchouc — Détermination de l'aromaticité des huiles dans les
mélanges vulcanisés
Reference number
ISO 21461:2009(E)
©
ISO 2009
---------------------- Page: 1 ----------------------
ISO 21461:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 21461:2009(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Reagents and materials . 1
5 Apparatus . 2
6 Procedure . 2
7 Calculation. 4
8 Precision. 5
9 Test report . 5
1
Annex A (informative) H NMR spectra of extracts from compounds containing aromatic oil
(Figures A.1 and A.3) and MES oil (Figures A.2 and A.4) . 6
1
Annex B (informative) H NMR analysis results for typical rubber compounds (those used for the
interlaboratory trial described in Clause 8) . 8
Annex C (informative) Preparation of clean samples of rubber compounds from tyres. 9
© ISO 2009 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 21461:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21461 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 3, Raw materials (including latex) for use in the rubber industry.
This second edition cancels and replaces the first edition (ISO 21461:2006), to which a new annex (Annex C)
has been added describing a procedure for the preparation of clean samples from the various components of
a tyre.
ISO 21461 is referenced in European regulation (EC) No. 1907/2006 concerning the Registration, Evaluation,
Authorization and Restriction of Chemicals (REACH) as the method used to measure and calculate bay
protons.
iv © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 21461:2009(E)
Rubber — Determination of the aromaticity of oil in vulcanized
rubber compounds
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all 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.
IMPORTANT — The electronic file of this document contains colours which are considered to be
useful for the correct understanding of the document. Users should therefore consider printing this
document using a colour printer.
1 Scope
This International Standard provides a method for the selective determination of polyaromaticity of oil in
vulcanized rubber compounds. The method is based on nuclear magnetic resonance (NMR) spectrometry.
2 Normative references
The following referenced documents are indispensable for the application 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
For the purposes of this document, the following terms and definitions apply.
3.1
polycyclic aromatic hydrocarbon
PAH
organic compound consisting of two or more aromatic rings, certain carbon atoms of which are common to
two or three rings
4 Reagents and materials
All reagents shall be of recognized analytical grade unless otherwise specified.
4.1 Extraction solvent
4.1.1 Acetone.
4.2 Sample preparation reagents
4.2.1 n-Hexane.
© ISO 2009 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 21461:2009(E)
4.2.2 Methylene chloride.
4.2.3 Nitrogen, purity > 99,9 %, for protecting the extract from oxidation during drying.
4.2.4 CDCl , 99,9 %, NMR grade.
3
4.2.5 Hexamethyldisiloxane (HMDS), 99,5 %, NMR grade, or tetramethylsilane (TMS), 99,5 %,
NMR grade.
5 Apparatus
5.1 Analytical balance, accurate to 0,1 mg.
5.2 Extraction apparatus, as specified in ISO 1407.
5.3 Steam bath.
5.4 Extract purification apparatus, consisting of the items specified in 5.4.1 to 5.4.5:
3 3 3 3
5.4.1 2 cm , 5 cm and 25 cm or 30 cm syringes, with conical end fittings, compatible with solid-phase
extraction (SPE) columns for manual purification operations.
1)
5.4.2 SPE cartridge containing 500 mg of silica gel.
5.4.3 Laboratory glassware.
5.4.4 (Optional) Solid-phase extraction equipment, connected to a vacuum pump, for simultaneous
purification of many extracts.
5.4.5 Disposable needles.
5.5 NMR spectrometer, at least 200 MHz, preferably with the following acquisition parameters:
1
probe: H;
pulse phase: 30°;
spectral width: − 2 ppm to + 12 ppm;
number of scans: 256;
relaxation delay: 2 s.
6 Procedure
6.1 Sample extraction
6.1.1 The laboratory sample shall be of sufficient size to provide at least 0,35 g of extracted oil.
Annex C gives guidance on the preparation of laboratory samples from tyres.
1) VARIAN BOND ELUT JR-SI, 500 mg, part number 12162037B, is an example of a suitable product available
commercially. This information is given for the convenience of users of this International Standard and does not constitute
an endorsement by ISO of this product. Equivalent products may be used.
2 © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 21461:2009(E)
6.1.2 Pass the sample between the rolls of a laboratory mill to reduce its thickness to less than 0,7 mm or,
alternatively, cut the sample in pieces smaller than 1 mm × 1 mm × 2 mm.
6.1.3 Wrap the sample in a small filter paper and insert it in the extractor (5.2), or fill the extractor with the
small cut pieces. Fill the flask of the extractor with acetone (4.1.1) and extract for 8 h.
6.1.4 Evaporate the extract to dryness under a stream of nitrogen (4.2.3) to prevent oxidation.
6.2 Purification of extract
3
6.2.1 Weigh, to the nearest 0,1 mg, 100 mg ± 5 mg of dry extract into a vial and dissolve it in 1 cm of
methylene chloride (4.2.2). There may be some insoluble matter.
3 3
6.2.2 Condition the SPE cartridge (5.4.2) by injecting 5 cm of n-hexane (4.2.1) onto it using a 5 cm
syringe (see 5.4.1).
6.2.3 When nearly all the n-hexane has drained out, transfer quantitatively the methylene chloride solution
3
onto the SPE cartridge and start collecting the eluate in a beaker or glass bottle. Use an additional 0,5 cm of
methylene chloride to rinse the vial and ensure complete transfer of the evaporation residue to the cartridge.
6.2.4 When nearly all the methylene chloride solution has been absorbed onto the SPE cartridge, start
3
eluting the non-polar fraction with 25 cm of hexane. During the elution, maintain a constant solvent flow not
3
exceeding a rate of 5 cm /min.
3
6.2.5 Stop collecting the purified fraction when all of the 25 cm of n-hexane has been added to the SPE
cartridge.
6.2.6 Evaporate the eluate to dryness under a stream of nitrogen to prevent oxidation.
6.2.7 Weigh the dry residue to the nearest 0,1 mg and calculate the percentage recovered.
6.2.8 Repeat the extract purification procedure two more times, taking a fresh portion of extract each time.
6.2.9 Calculate the average of the three percentage recovery values. If the individual values obtained are
within ± 5 % of the average, proceed to 6.3. Otherwise, repeat the sample extraction and extract purification
procedure until three values within ± 5 % of the average are obtained.
6.3 NMR analysis
6.3.1 General
1
The aromatic character of the oil present in the dry residue obtained in 6.2.7 is determined by means of H
NMR spectroscopy.
6.3.2 Principle
The molecular structure of non-linear PAHs with three or more fused rings contains a characteristic three-
sided concave area, located at the periphery of the molecule. The hydrogen atoms in this area are called bay
region hydrogens (see Figure 1).
1
H NMR spectroscopy can identify and quantify selectively the hydrogen atoms in the bay region, which are
characteristic of aromatic oils.
This method describes a procedure for determining the percentage of bay region hydrogens (% H ) in a
Bay
1
sample solution by H NMR, thus giving an indication of the aromatic character of the oil.
The higher the percentage of bay region hydrogens, the higher the aromaticity.
© ISO 2009 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO 21461:2009(E)
a) Benzopyrene b) 7,12-Dimethylbenzanthracene c) 5-Methylchrysene
Key
1 bay region
Figure 1
6.3.3 NMR measurement
3
6.3.3.1 Dissolve one of the dry residues obtained in 6.2.7 a
...
INTERNATIONAL ISO
STANDARD 21461
Second edition
2009-03-01
Rubber — Determination of the
aromaticity of oil in vulcanized rubber
compounds
Caoutchouc — Détermination de l'aromaticité des huiles dans les
mélanges vulcanisés
Reference number
ISO 21461:2009(E)
©
ISO 2009
---------------------- Page: 1 ----------------------
ISO 21461:2009(E)
PDF disclaimer
PDF files may contain embedded typefaces. In accordance with Adobe's licensing policy, such files may be printed or viewed but shall
not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading a PDF file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create the PDF file(s) constituting this document can be found in the General Info relative to
the file(s); the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the files are suitable for
use by ISO member bodies. In the unlikely event that a problem relating to them is found, please inform the Central Secretariat at the
address given below.
This CD-ROM contains the publication ISO 21461:2009 in portable document format (PDF), which can be
viewed using Adobe® Acrobat® Reader.
Adobe and Acrobat are trademarks of Adobe Systems Incorporated.
IMPORTANT — The electronic file of this document contains colours which are considered to be
useful for the correct understanding of the document. Users should therefore consider printing this
document using a colour printer.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless required for installation or otherwise specified, no part of this CD-ROM may be reproduced, stored in a retrieval
system or transmitted in any form or by any means without prior permission from ISO. Requests for permission to reproduce this product
should be add
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.