1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 7270-2:2012 Rubber Analysis by pyrolytic gas-chromatographic methods Part 2: Determination of styrene/butadiene/ isoprene ratioBS ISO 7270-2:2012 BRITISH STANDARD Natio
2、nal foreword This British Standard is the UK implementation of ISO 7270-2:2012. It supersedes BS ISO 7270-2:2005 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/23, Test methods for rubber and non-black compounding ingredients. A list of organizat
3、ions represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012
4、ISBN 978 0 580 65977 5 ICS 83.060 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2012. Amendments issued since publication Date Text affectedBS ISO
5、7270-2:2012 ISO 2012 Rubber Analysis by pyrolytic gas- chromatographic methods Part 2: Determination of styrene/butadiene/ isoprene ratio Caoutchouc Mthodes danalyse par pyrolyse et chromatographie en phase gazeuse Partie 2: Dtermination du rapport styrne/butadine/isoprne INTERNATIONAL STANDARD ISO
6、7270-2 Second edition 2012-09-15 Reference number ISO 7270-2:2012(E)BS ISO 7270-2:2012ISO 7270-2:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
7、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 requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mai
8、l copyrightiso.org Web www.iso.org Published in SwitzerlandBS ISO 7270-2:2012ISO 7270-2:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv 1 Scope 1 2 Normative references . 1 3 Principle . 1 4 Reagents 1 5 Apparatus 2 5.1 Extraction apparatus 2 5.2 Pyrolysis/gas chromatography syste
9、m . 2 6 Procedure 3 6.1 Preparation of test samples from calibration samples and unknown sample . 3 6.2 Test conditions . 3 6.3 Preparation of calibration curves . 6 6.4 Analysis of the unknown sample 7 7 Expression of results . 8 8 Precision 8 9 Test report . 8 Annex A (informative) Precision . 9 B
10、ibliography . 11BS ISO 7270-2:2012ISO 7270-2:2012(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. E
11、ach 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 Internati
12、onal 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 Standa
13、rds 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
14、 of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7270-2 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This second edition cancels and replaces the first edition (ISO 7270-2:20
15、05), which has been technically revised. ISO 7270 consists of the following parts, under the general title Rubber Analysis by pyrolytic gas- chromatographic methods: Part 1: Identification of polymers (single polymers and polymer blends) Part 2: Determination of styrene/butadiene/isoprene ratio iv I
16、SO 2012 All rights reservedBS ISO 7270-2:2012INTERNATIONAL STANDARD ISO 7270-2:2012(E) Rubber Analysis by pyrolytic gas-chromatographic methods Part 2: Determination of styrene/butadiene/isoprene ratio WARNING Persons using this part of ISO 7270 should be familiar with normal laboratory practice. Th
17、is part of ISO 7270 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. CAUTION Certain procedures specifie
18、d in this part of ISO 7270 might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use. 1 Scope This part of ISO 7270 specifies a pyrol
19、ytic gas-chromatographic method for the determination of the styrene/butadiene/isoprene ratio in copolymers, or blends of homopolymers and/or copolymers, in raw rubbers or in unvulcanized or vulcanized compounds. It is applicable to copolymers/terpolymers consisting of styrene, butadiene and isopren
20、e, and blends of these polymers. NOTE 1 The use of this part of ISO 7270 pre-supposes sufficient working knowledge of the principles and techniques of gas chromatography for the analyst to perform the operations described and interpret the results correctly. NOTE 2 The styrene/butadiene/isoprene rat
21、io determined by this test method is affected by the presence of resin and by a high level of sulfur. 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 la
22、test edition of the referenced document (including any amendments) applies. ISO 1407:2011, Rubber Determination of solvent extract 3 Principle Calibration curves are first prepared by pyrolysing samples with known styrene/butadiene/isoprene ratios and analysing the pyrolysis products by gas chromato
23、graphy to determine the percentage content of each component (styrene, butadiene and isoprene), relative to the total of the three components. Samples of unknown composition are then pyrolysed, and the pyrolysis products are analysed under the same conditions. The styrene/butadiene/isoprene ratio in
24、 these samples is determined from the calibration curves. 4 Reagents All reagents shall be of analytical grade. 4.1 Solvents for extraction purposes. The following solvents are suitable: acetone; ISO 2012 All rights reserved 1BS ISO 7270-2:2012ISO 7270-2:2012(E) methanol; methylethylketone. 4.2 Carr
25、ier gas: nitrogen; or helium. 4.3 Gas for flame-ionization detector: hydrogen plus purified compressed air. 5 Apparatus 5.1 Extraction apparatus As specified in ISO 1407. 5.2 Pyrolysis/gas chromatography system 5.2.1 General The apparatus utilized to obtain pyrograms consists of four parts: the pyro
26、lysis device, the gas chromatograph, the gas-chromatographic column and the data-handling equipment. 5.2.2 Pyrolysis device The following types of pyrolysis device are suitable: micro-furnace pyrolyser; Curie-point pyrolyser; platinum-filament pyrolyser. 5.2.3 Gas chromatograph A wide variety of gas
27、 chromatographs using either a flame-ionization detector (FID) or a thermal-conductivity detector (TCD) are suitable for use in this part of ISO 7270. An FID is preferable for use with capillary columns. 5.2.4 Chromatographic columns A variety of column materials, column lengths, column diameters an
28、d stationary and liquid phases are suitable for use in this part of ISO 7270, the main requirement being high resolution of the volatile pyrolysis products styrene, butadiene and isoprene. NOTE 1 Capillary columns, which have a separation efficiency which is better than that of packed columns, are s
29、uitable, but not essential. NOTE 2 Capillary columns containing non-polar polydimethylsiloxanes and partially modified (diphenyl-, cyanopropylphenyl- or other) semi-polar silicones are suitable. NOTE 3 When using an ordinary (30 m) capillary column, it is difficult to separate isobutene from butadie
30、ne completely. The reason is that, in pyrolytic gas-chromatographic methods, isobutene, which is a decomposition product of rubber containing the isoprene unit, is detected close to the retention time of butadiene. It is possible, however, to discriminate between isoprene and butadiene, even without
31、 complete separation, by means of the calibration curves. 2 ISO 2012 All rights reservedBS ISO 7270-2:2012ISO 7270-2:2012(E) 5.2.5 Data-handling equipment A recorder, an integrator or a computer data-analysis system may be used. 6 Procedure 6.1 Preparation of test samples from calibration samples an
32、d unknown sample 6.1.1 A minimum of three calibration samples shall be used for the preparation of the calibration curves, including a calibration sample with the composition expected for the unknown sample under test. 6.1.2 The nature (raw, unvulcanized, or vulcanized) of the calibration samples sh
33、ould preferably be the same as that of the unknown sample under test. 6.1.3 Process or extender oil and additives in both the calibration samples and the unknown sample shall be extracted in accordance with ISO 1407:2011, method B, using a solvent suitable for the type of compound concerned (vulcani
34、zed or unvulcanized). The solvent chosen shall not affect the polymer and shall remove as much of the process and extender oil and additives as possible. All samples shall be dried after extraction, using the drying procedure specified in method B of ISO 1407:2011. NOTE Process and extender oils can
35、 cause serious interference. 6.1.4 From the extracted samples, take test samples of masses appropriate to the pyrolyser used, and as small and as equal as possible for improved reproducibility. NOTE Generally, the mass will be between 0,1 mg and 5 mg, depending on the pyrolyser. 6.2 Test conditions
36、6.2.1 The test conditions, including the pyrolysis temperature, shall be the same for the preparation of the calibration curves and the analysis of the unkown sample. 6.2.2 An appropriate pyrolysis temperature is 500 C to 600 C for a micro-furnace or Curie-point pyrolyser, and 600 C to 750 C for a p
37、latinum-filament pyrolyser. 6.2.3 The gas-chromatographic conditions will depend on the column used. Typical operating conditions are given in Tables 1 to 3, and examples of chromatograms obtained using each set of conditions are given in Figures 1 to 3. ISO 2012 All rights reserved 3BS ISO 7270-2:2
38、012ISO 7270-2:2012(E) Table 1 Recommended operating conditions for micro-furnace pyrolysis followed by chromatography with a 30 m capillary column Pyrolysis Device Pyrolysis temperature Micro-furnace 550 C Gas-chromatographic column Liquid phase Film thickness Column diameter/material Column length
39、5 % diphenyldimethylpolysiloxane 1,0 m 0,25 mm ID/stainless steel (deactivated) 30 m Chromatographic conditions Carrier gas and flow rate Injector temperature Type of detector Detector temperature Helium, 0,8 ml/min 250 C FID 300 C Temperature programme Isothermal for 2 min at 50 C then increase at
40、20 C/min from 50 C to 280 C then isothermal for 10 min at 280 C Table 2 Recommended operating conditions for micro-furnace pyrolysis followed by chromatography with a 60 m capillary column Pyrolysis Device Pyrolysis temperature Micro-furnace 550 C Gas-chromatographic column Liquid phase Film thickne
41、ss Column diameter/material Column length 5 % diphenyldimethylpolysiloxane 1,0 m 0,25 mm ID/stainless steel (deactivated) 60 m Chromatographic conditions Carrier gas and flow rate Injector temperature Type of detector Detector temperature Helium, 0,8 ml/min 250 C FID 300 C Temperature programme Isot
42、hermal for 7 min at 50 C then increase at 10 C/min from 50 C to 280 C then isothermal for 10 min at 280 C 4 ISO 2012 All rights reservedBS ISO 7270-2:2012ISO 7270-2:2012(E) Table 3 Recommended operating conditions for Curie-point pyrolysis followed by chromatography with a packed column Pyrolysis De
43、vice Pyrolysis temperature/time Curie-point pyrolyser 590 C/3 s Gas-chromatographic column Liquid phase Column diameter/material Column length 20 % silicone 710/Chromosorb W (60 to 80 mesh) 3 mm ID/stainless steel 3 m Chromatographic conditions Carrier gas Type of detector Helium FID Temperature pro
44、gramme Isothermal for 2 min at 50 C then increase at 10 C/min from 50 C to 220 C then isothermal for 10 min at 220 C 4 6 8 10 12 14 16 1 2 3 1 0 2 18 X Key X time (min) 1 butadiene 2 isoprene 3 styrene Figure 1 Example of chromatogram obtained with 30 m capillary column ISO 2012 All rights reserved
45、5BS ISO 7270-2:2012ISO 7270-2:2012(E) 2 4 6 8 10 12 14 16 18 20 22 24 26 28 1 1 2 3 X Key X time (min) 1 butadiene 2 isoprene 3 styrene Figure 2 Example of chromatogram obtained with 60 m capillary column 4 1 2 3 81 21 62 02 42 8 X Key X time (min) 1 butadiene 2 isoprene 3 styrene Figure 3 Example o
46、f chromatogram obtained with packed column 6.3 Preparation of calibration curves 6.3.1 Place a test sample taken from one of the extracted calibration samples in the pyrolysis device, pyrolyse it, and analyse the pyrolysis products with the gas chromatograph to obtain the pyrogram. Repeat this step
47、for the other calibration samples in order to prepare the calibration curves. 6 ISO 2012 All rights reservedBS ISO 7270-2:2012ISO 7270-2:2012(E) 6.3.2 Record the peak areas P ST , P BDand P IPfor styrene, butadiene and isoprene, respectively, obtained from the data-handling equipment (5.2.5). Calcul
48、ate the percentage peak area for each of these components, A ST , A BDand A IP , relative to their total, as follows: where A ST is the percentage peak area for styrene; A BD is the percentage peak area for butadiene; A IP is the percentage peak area for isoprene; P ST is the peak area for styrene;
49、P BD is the peak area for butadiene; P IP is the peak area for isoprene. 6.3.3 For each of the three components, styrene, butadiene and isoprene, prepare a calibration curve. For styrene, for example, plot the known percentage of styrene (relative to the total of the three) on the X -axis against the percentage peak area obtained for styrene in the pyrolysis prod
