1、 Reference number ISO 4901:2011(E) ISO 2011INTERNATIONAL STANDARD ISO 4901 Second edition 2011-08-15 Reinforced plastics based on unsaturated-polyester resins Determination of the residual styrene monomer content, as well as the content of other volatile aromatic hydrocarbons, by gas chromatography
2、Plastiques renforcs base de rsines de polyesters non saturs Dtermination du styrne monomre rsiduel, ainsi que dautres hydrocarbures aromatiques volatils, par chromatographie en phase gazeuse ISO 4901:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no pa
3、rt 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 requester. ISO copyright office Case postale
4、56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedISO 4901:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and
5、 definitions . 1 4 Principle . 1 5 Materials . 2 6 Apparatus . 2 7 Preparation of sample . 3 8 Procedure . 3 8.1 General . 3 8.2 Preparation of extraction solvent 3 8.3 Preparation of test solution 3 8.4 Determination of glass and mineral content 3 8.5 Preparation of calibration solutions 4 8.6 Gas-
6、chromatographic procedure 4 9 Expression of results 6 9.1 Calculation of results from a calibration graph . 6 9.2 Calculation of the content of styrene (or another aromatic hydrocarbon) in the original UP resin sample . 7 9.3 Calculation of the content of styrene (or another aromatic hydrocarbon) in
7、 the pure UP resin 8 10 Test report 8 Annex A (informative) Typical operating conditions . 9 ISO 4901:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of prepa
8、ring 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 l
9、iaison 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 o
10、f 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 i
11、s 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 4901 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials. T
12、his second edition cancels and replaces the first edition (ISO 4901:1985), which has been technically revised (for details, see the Introduction). ISO 4901:2011(E) ISO 2011 All rights reserved vIntroduction During the 25 years since publication of the first edition of this International Standard, IS
13、O 4901:1985, significant advances have been made in analytical techniques such as gas chromatography. The standard has therefore been completely revised. The following are the main changes which have been made: a) In addition to a gas-chromatographic method, the first edition of ISO 4901 included, a
14、s an alternative, a classical method, Wijs method, based on an iodometric titration. This method had been included in the first edition for laboratories in which gas chromatography was not available. As, nowadays, chromatography is considered to be a routine analytical tool, Wijs method has been rem
15、oved from the standard. b) Packed gas-chromatography columns have generally been replaced by open, tubular columns which operate under completely different conditions. In the revised test method, therefore, only an open, tubular column is used. c) In addition, the gas-chromatographic method has been
16、 extended to cover not only styrene but also other aromatic hydrocarbons which might have been used as solvents or starting materials in producing the unsaturated polyester resin. INTERNATIONAL STANDARD ISO 4901:2011(E) ISO 2011 All rights reserved 1Reinforced plastics based on unsaturated-polyester
17、 resins Determination of the residual styrene monomer content, as well as the content of other volatile aromatic hydrocarbons, by gas chromatography WARNING Persons using this document should be familiar with normal laboratory practice, if applicable. This document does not purport to address all of
18、 the safety concerns, 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 regulatory requirements. 1 Scope This International Standard specifies a method for the determination, by gas chromatogra
19、phy, of the residual styrene monomer in reinforced plastics based on unsaturated polyester (UP) resins in the polymerized state. The residual styrene monomer content is an important criterion in evaluating the degree of cure of UP resins in the polymerized state. The method can also be used for the
20、simultaneous determination of other volatile aromatic hydrocarbons in UP resins. The method is not applicable to UP resins of high chemical resistance. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edi
21、tion cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 472, Plastics Vocabulary ISO 1172, Textile-glass-reinforced plastics Prepregs, moulding compounds and laminates Determination of the textile-glass and mineral-filler cont
22、ent Calcination methods 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 472 apply. 4 Principle Styrene is extracted from the UP resin in the polymerized state using dichloromethane. The styrene in the extract is determined by gas chromatography, usin
23、g an internal standard and a calibration curve. ISO 4901:2011(E) 2 ISO 2011 All rights reserved5 Materials 5.1 n-Butylbenzene, analytical grade, for use as an internal standard. 5.2 Dichloromethane, analytical grade, for use as the extraction solvent. WARNING Dichloromethane is harmful when swallowe
24、d, inhaled or absorbed through the skin. It affects the central nervous system, the liver, the cardiovascular system and the blood. It causes irritation of the skin, eyes and respiratory tract. It is also a suspected cancer hazard, the risk of cancer depending on the level and duration of exposure.
25、NOTE In view of the toxicity and suspected carcinogenic characterics of dichloromethane, acetone and ethyl acetate are being tested as replacements. If the results of this work demonstrate conclusively that either one or both of these solvents are suitable, this International Standard will be revise
26、d accordingly. 5.3 Styrene, analytical grade, and, if relevant, other aromatic hydrocarbons, such as toluene, ethylbenzene and -methylstyrene, also analytical grade. NOTE An aromatic hydrocarbon is considered to be relevant if it is used as a solvent or starting material in the UP resin production p
27、rocess. 5.4 Carrier gas and FID fuel gases: carrier gas: helium or nitrogen; FID fuel gases: hydrogen and air. 6 Apparatus Normal laboratory equipment and the following apparatus are required: 6.1 Cutting device, equipped with a water-cooled diamond blade, for cutting the UP resin into strips of wid
28、th 1 mm to 2 mm. 6.2 Gas chromatograph, including the following components: 6.2.1 Injection port, equipped with a splitter, for use with liquid samples. 6.2.2 Open, tubular column, e.g. meeting the specifications given in Annex A. 6.2.3 Flame ionization detector (FID). A typical instrument setup and
29、 typical operating conditions are given in Annex A. Other setups and operating conditions may be used provided that the chromatograms obtained comply with the requirements given in 8.6.1. 6.3 Data processor, e.g. a computer (or the equivalent), to record the signals from the detector. 6.4 Sample inj
30、ection syringe, i.e. a 1 l microsyringe, either as a separate item of apparatus or incorporated in the auto-injector of the gas chromatograph. 6.5 Analytical balance, accurate to 0,1 mg. ISO 4901:2011(E) ISO 2011 All rights reserved 37 Preparation of sample Polymerized UP resin pieces of any shape t
31、hat will permit the production of strips of width 1 mm to 2 mm may be used. Cut the polymerized pieces into strips of width 1 mm to 2 mm. Dry the strips and break them into pieces of length approximately 10 mm. During cutting and drying, avoid any operation that could affect the styrene and/or volat
32、ile-hydrocarbon content. 8 Procedure 8.1 General Three test portions of the sample (see Clause 7) shall be analysed. During the preparation, dilution and extraction processes described below, the temperature of all solutions shall remain 25 C. 8.2 Preparation of extraction solvent Weigh, to the near
33、est 0,1 mg, (250 50) mg of n-butylbenzene (5.1) into a 1 000 ml volumetric flask containing approximately 500 ml of dichloromethane (5.2). Make up to the mark with dichloromethane (see, however, next paragraph) and mix. Alternatively, acetone (see Note to 5.2) may be used instead of dichloromethane,
34、 provided that the results can be demonstrated to be equivalent to those obtained with dichloromethane. In cases of dispute, dichloromethane shall be used. 8.3 Preparation of test solution Weigh, to the nearest 0,1 mg, into a 50 ml conical flask a test portion of a size depending on the styrene mono
35、mer content expected (see Table 1). Add 15,00 ml of extraction solvent (see 8.2), close the flask with a suitable stopper and allow the suspension to stand for 15 h to 20 h with occasional shaking. After shaking for the last time, allow the precipitate to settle. The supernatant solution is used for
36、 injection into the gas chromatograph. Table 1 Size of test portion as a function of expected styrene monomer concentration Expected styrene monomer concentration % by mass Size of test portion mg 0,5 1 000 0,5 but 1 500 1 but 1,5 250 1,5 but 3 150 3 100 8.4 Determination of glass and mineral conten
37、t If the content of styrene or another aromatic hydrocarbon is to be calculated on the basis of the resin content of a UP resin containing glass and/or a mineral filler, calcine a portion of the sample (see Clause 7) in accordance with ISO 1172 and determine the glass content, the filler content or
38、both, as applicable. ISO 4901:2011(E) 4 ISO 2011 All rights reserved8.5 Preparation of calibration solutions 8.5.1 General The range of concentrations of the calibration solutions which will need to be prepared will depend on the expected styrene content of the sample and the expected content of any
39、 other aromatic hydrocarbons to be determined, as well as on the size of the test portion taken (see Table 1). A series of calibration solutions shall be prepared for each aromatic hydrocarbon to be determined. 8.5.2 Preparation of styrene stock solution Weigh, to the nearest 0,1 mg, (250 10) mg of
40、styrene (see 5.3) into a 250 ml volumetric flask containing 100 ml of extraction solvent (see 8.2). Make up to the mark with extraction solvent and mix. Using the same procedure, prepare stock solutions of any other aromatic hydrocarbons to be determined. 8.5.3 Preparation of calibration solutions P
41、repare at least five different calibration solutions in accordance with the dilution scheme given in Table 2, taking the volume of stock solution indicated in a 50 ml volumetric flask and making up to the mark with extraction solvent (see 8.2) and mixing. Table 2 Preparation scheme for calibration s
42、olutions Styrene concentration in calibration solution amg/l Volume of stock solution taken ml Volumetric flask used ml 0 Undiluted extraction solvent (see 8.2) 0,02 m a0,25 50 0,08 m a1 50 0,2 m a2,5 50 0,4 m a5 50 0,8 m a10 50 1,2 m a15 50 1,6 m a20 50 2 m a 25 50 am ais the actual amount of styre
43、ne, in milligrams, weighed out in 8.5.2. 8.6 Gas-chromatographic procedure 8.6.1 Gas-chromatograph operating conditions It is important that the gas-chromatographic conditions give sufficient separation of styrene and the other compounds eluted. The chromatograms prepared shall therefore satisfy the
44、 following requirement. The peak resolution R ebetween the target peaks (i.e. those corresponding to styrene, any other aromatic hydrocarbons to be determined and the internal standard) and the peaks corresponding to components appearing just before or just after the target peaks shall be more than
45、1,5. ISO 4901:2011(E) ISO 2011 All rights reserved 5The resolution R ebetween two peaks of the same area is defined as follows: 21 e 12 2tt R WW where t 1and t 2are the retention times for the two peaks, in seconds; W 1and W 2are the respective peak widths at the base of the peaks, in seconds. The g
46、as-chromatographic conditions shall be optimized to give the performance specified above. General details of the gas-chromatographic setup are given below. Typical operating conditions are described in Annex A. Column: open, tubular fused-silica column. Carrier gas: helium or nitrogen. Detector FID
47、with a hydrogen/air flame. Adjust the rates of flow of the hydrogen and air to the FID to give: a high sensitivity of response; a linear response over the concentration range used; only insignificant effects of small changes in flow rate on response and sensitivity. 8.6.2 Recording the gas chromatog
48、rams of test solution and calibration solutions Inject a suitable volume, which will depend on the sensitivity of the gas chromatograph used, of the test solution prepared in accordance with 8.3 and of each of the calibration solutions prepared in accordance with 8.5. The volume of test solution inj
49、ected shall be identical to the volume of each of the corresponding calibration solutions injected. Continue to record each chromatogram until all components, such as solvent, styrene, other aromatic hydrocarbons to be determined and internal standard, have been completely eluted. 8.6.3 Evaluation of the gas-chromatographic peaks The relative retention times of styrene, any other aromatic hydrocarbons to be determined and the internal standard shall be determined in ad
