1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 21461:2012Rubber Determination of thearomaticity of oil in vulcanizedrubber compoundsBS ISO 21461:2012 BRITISH STANDARDNational forewordThis British Standard is the UK imp
2、lementation of ISO 21461:2012. Itsupersedes BS ISO 21461:2009 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/23, Test methods for rubber and non-blackcompounding ingredients.A list of organizations represented on this committee can beobtained on re
3、quest to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 75081 6ICS 83.040.10Compliance with a British
4、Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 June 2012.Amendments issued since publicationDate Text affectedBS ISO 21461:2012 ISO 2012Rubber Determination of the aromaticity of oil in
5、 vulcanized rubber compoundsCaoutchouc Dtermination de laromaticit des huiles dans les mlanges vulcanissINTERNATIONAL STANDARDISO21461Third edition2012-06-01Reference numberISO 21461:2012(E)BS ISO 21461:2012ISO 21461:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All righ
6、ts 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 ISOs member body in the country of the
7、 requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 21461:2012ISO 21461:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Ter
8、ms and definitions . 14 Reagents and materials . 14.1 Extraction 14.2 Sample preparation reagents . 15 Apparatus 26 Procedure 36.1 Sample extraction . 36.2 Extract purification . 36.3 NMR analysis 47 Calculation 68 Test report . 6Annex A (informative) 1H NMR spectra of extracts from compounds contai
9、ning aromatic oil (Figures A.1 and A.3) and MES oil (Figures A.2 and A.4) 8Annex B (informative) Preparation of clean samples of rubber compounds from tyres 10Annex C (informative) Precision statement .18Bibliography .19BS ISO 21461:2012ISO 21461:2012(E)ForewordISO (the International Organization fo
10、r 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
11、 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.Internatio
12、nal 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
13、 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
14、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 third edition cancels and replaces the second edition (ISO 21461:2009), which has been technically revised. In the reagents, n-hexan
15、e has been replaced by n-heptane and methylene chloride is no longer used. The precision data have been improved and transferred to an informative annex (Annex C).iv ISO 2012 All rights reservedBS ISO 21461:2012INTERNATIONAL STANDARD ISO 21461:2012(E)Rubber Determination of the aromaticity of oil in
16、 vulcanized rubber compoundsWARNING 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 a
17、nd 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
18、printer.1 ScopeThis 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 referencesThe following referenced documents are indispensable for t
19、he 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 extract3 Terms and definitionsFor the purposes of this document, t
20、he following terms and definitions apply.3.1PAHpolycyclic aromatic hydrocarbonorganic compounds consisting of two or more aromatic rings where certain carbon atoms are common to two or three rings4 Reagents and materialsAll reagents shall be of recognized analytical grade unless specified in a diffe
21、rent way.4.1 Extraction4.1.1 Acetone.4.2 Sample preparation reagents4.2.1 n-Heptane, pa grade.4.2.2 Nitrogen, purity required 99,9 %, for protecting the extract from oxidation during the drying step.4.2.3 Hexamethyldisiloxane (HMDS), 99,5 %, NMR grade, or tetramethylsilane (TMS), 99,5 %, NMR grade.
22、ISO 2012 All rights reserved 1BS ISO 21461:2012ISO 21461:2012(E)4.2.4 Deuterated chloroform (CDCl3), 99,95 % deuteration degree, NMR grade containing 0,05 % TMS or 0,03 % HMDS (4.2.3). The resonance peak of either TMS or HMDS is used for the calibration of the horizontal scale of the spectrum.4.2.5
23、Acetaldehyde, purity 99,5 %, may optionally be added at a concentration of 0,6 % to the deuterated chloroform containing the TMS or HMDS (4.2.4). The added acetaldehyde provides a resonance peak at around 9,8 ppm which is useful for a good phasing of the spectrum. The solution has to be prepared fre
24、shly in order to avoid interference from acetaldehyde decomposition products formed upon ageing.5 Apparatus5.1 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.
25、4.4.5.4.1 For single sample purification at one time (manually operated filtration):a) 2 cm3, 5 cm3, 10 cm3and 25 cm3or 30 cm3syringes with conical end fitting compatible with solid phase extraction (SPE) columns for manually operated purification.b) SPE cartridge containing 500 mg or 1 000 mg of si
26、lica gel1).5.4.2 For simultaneous purification of multiple samples (optional):a) 2 cm3, 5 cm3, 10 cm3and 25 cm3or 30 cm3syringes with conical end fitting compatible with Solid Phase Extraction (SPE) columns for manually operated purification.b) SPE cartridge containing 500 mg or 1 000 mg of silica g
27、el2).c) Solid phase filtration equipment connected to a vacuum pump, for simultaneous purification of many samples3).d) Glass test tubes, to collect the filtrate and compatible with the filtration device4).5.4.3 Laboratory glassware.5.4.4 Disposable needle.5.5 NMR spectrometer, at least 200 MHz, pre
28、ferably with the following acquisition parameters: probe: 1H;1) Varian Bond Elut JR-SI, 1 000 mg, Part number: 12166008B or equivalent. This is an example of a suitable supplier. This information is given for the convenience of users of this International Standard and does not constitute an endorsem
29、ent by ISO of this supplier.2) Varian Bond Elut Mega BE-SI, 1 000 mg, Part number: 12256008 or equivalent. This is an example of a suitable supplier. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this supplier.3
30、) Varian Vac Elut 20 Manifold with tall glass basin, Part number: 12234104 or equivalent. This is an example of a suitable supplier. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this supplier.4) For Varian Vac
31、Elut 20, test tubes 16 mm diameter X 150 mm length.2 ISO 2012 All rights reservedBS ISO 21461:2012ISO 21461:2012(E) pulse phase: 30; spectral width: 2 ppm to + 12 ppm; number of scans: 256; relaxation delay: 2 s.6 Procedure6.1 Sample extraction6.1.1 The compound sample shall be of sufficient size to
32、 provide at least 350 mg of extracted oil. In case of tyres, refer to Annex B for sample preparation.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
33、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 (4.2.2) to prevent oxidation.6.2 Extract purificati
34、on6.2.1 Weigh the dried extract to the nearest 0,1 mg. Add the amount of n-heptane (4.2.1) necessary to bring the concentration to 100 mg/cm3. There may be some insoluble matter. Prepare three vials containing 1 cm3each of the n-heptane solution.6.2.2 Condition the SPE cartridge (see 5.4.1 or 5.4.2)
35、 by eluting 5 cm3or 10 cm3of n-heptane (4.2.1) using the 5 cm3or 10 cm3syringe (see 5.4.1 or 5.4.2).6.2.3 When the n-heptane is nearly completely eluted, transfer quantitatively the n-heptane solution from one vial (6.2.1) onto the SPE cartridge and start the collection in a beaker or glass test tub
36、e. Use an additional 0,5 cm3n-heptane portion to rinse the vial and ensure complete transfer of the evaporation residue.6.2.4 When the n-heptane solution is nearly absorbed onto the SPE cartridge, elute the non-polar fraction with 25 cm3of n-heptane. During the elution, maintain a constant solvent f
37、low not exceeding a rate of 5 cm3/min.6.2.5 Stop collecting the purified fraction when all of the 25 cm3of n-heptane has been added to the SPE cartridge.6.2.6 Evaporate the eluted residue to dryness under a stream of nitrogen (4.2.2) to prevent oxidation. In order to accelerate the final drying step
38、, the sample can be put in a vacuum oven at 50 C for 2 h to 3 h.6.2.7 Weigh the dry residue to the nearest 0,1 mg and calculate the percentage of recovery.6.2.8 Repeat the extract purification procedure two more times, using the other two vials prepared in advance in step 6.2.1.6.2.9 Calculate the a
39、verage value of the three percentages of recovery (from 6.2.7). If the individual values obtained are within 5 % of the average, proceed to 6.3. Otherwise repeat the sample preparation until three values are within 5 % of the average recovery. ISO 2012 All rights reserved 3BS ISO 21461:2012ISO 21461
40、:2012(E)6.3 NMR analysis6.3.1 PrincipleThe aromatic character of the oil present in the dry residues obtained in 6.2.7 and 6.2.8 is determined by means of 1H-NMR spectroscopy.The molecular structure of non-linear PAH with three or more fused rings contains a characteristic three-sided concave area,
41、located at the periphery of the aromatic hydrocarbon molecule: these specific hydrogen atoms in this area are called bay region hydrogens (see Figure 1).1H-NMR spectroscopy can identify and quantify selectively the hydrogen atoms in the bay region, which are characteristic for aromatic oils.This met
42、hod describes the procedure to determine the percentage of bay region hydrogens (% HBay) in a sample solution by 1H-NMR, thus concluding on the aromatic character of the oil.The higher the amount of bay region hydrogens, the higher is the aromaticity.a) Benzopyrene b) 7,12-Dimethylbenzanthracene c)
43、5-MethylchryseneKey1 bay regionFigure 1 6.3.2 NMR measurement6.3.2.1 Dissolve one of the dry residues obtained in 6.2.7 and 6.2.8 in a glass vial for example, about 1 cm3of CDCl3(4.2.4) for a 5 mm tube. If necessary, enhance dissolution by using a small magnetic stirrer or mechanical shaker; if this
44、 is not enough, add more CDCl3.6.3.2.2 Acquire the free induction decay (FID) signal and apply a Fourier transform, multiplying by an exponential function (LB = 0,3 Hz) to obtain the spectrum (see the examples in Annex A). Adjust the resonance of the reference peak to 0,00 ppm for TMS, or to 0,06 pp
45、m for HMDS, respectively.6.3.2.3 Correct the baseline of the spectrum.6.3.2.4 Correct the baseline by using a cubic spline correction, setting points for the correction at 11,5 ppm, 10,5 ppm, 6,0 ppm, 0,5 ppm and 1,5 ppm. An example of a spectrum after phase correction and after baseline correction
46、is shown in Figure 2.6.3.2.5 Integrate the spectrum and record the following areas:4 ISO 2012 All rights reservedBS ISO 21461:2012ISO 21461:2012(E)I0the aromatic proton area, from 6,0 ppm to 9,5 ppm, including the CHCl3signal (impurity contained in CDCl3);I00the area of the aliphatic and ethylenic p
47、roton regions from 0,2 ppm to 5,8 ppm, including the water signal (water from CDCl3) at around 1,5 ppm;I2the area of the bay proton region from 8,3 ppm to 9,5 ppm.6.3.2.6 As a solvent blank, measure the 1H-NMR spectrum of the deuterated chloroform containing TMS or HMDS (4.2.4). Using this blank, th
48、e aromatic area I0and the aliphatic and ethylenic area I00are corrected for the solvent impurity (CHCl3) and the water content of the solvent.The corrections above are done using the following equations:II10= CHTMSTMSblankblank(1a)orII10= CHHMDSHMDSblankblank(1b)II300= WaterTMSTMSblankblank(2a)orII3
49、00= WaterHMDSHMDSblankblank(2b)whereCHblankis the integrated area from 6,0 ppm and 9,5 ppm in deuterated chloroform containing TMS or HMDS (4.2.4);Waterblankis the integrated area from 1,0 ppm to 1,8 ppm in deuterated chloroform containing TMS or HMDS (4.2.4). This integrated signal intensity accounts for the water content in the solvent;TMSblankor HMDSblankis the integrated signal intensity of TMS (or HMDS) in deuterated chloroform containing TMS or HMDS (4.2.4);TMS or HMDS is the inte
