1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58acrylonitrile contentICS 83.040.10Rubber Nitrile latex Determination of residual BRITISH STANDARDBS
2、 ISO 3899:2005BS ISO 3899:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 6 January 2006 BSI 6 January 2006ISBN 0 580 47165 9Cross-referencesThe British Standards which implement international publications referred to in this document may
3、 be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users ar
4、e responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 3 and a back cover.The
5、BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsA list of organizations represented on this committee can be obtained on request to its secretary. present to the responsible international/European co
6、mmittee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard reproduces verbatim ISO 3899:2005 and implements it as the UK national st
7、andard. It supersedes BS 6057-3.22:1990 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/50, Rubber-raw, natural and synthetic, including latex and carbon black, which has the responsibility to: aid enquirers to understand the text;Reference numberI
8、SO 3899:2005(E)INTERNATIONAL STANDARD ISO3899Third edition2005-10-01Rubber Nitrile latex Determination of residual acrylonitrile content Caoutchouc Latex de nitrile Dtermination de la teneur en acrylonitrile rsiduel BS ISO 3899:2005ii iiiForeword ISO (the International Organization for Standardizati
9、on) 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 re
10、presented 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
11、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 Internati
12、onal 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 3899 was pr
13、epared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This third edition cancels and replaces the second edition (ISO 3899:1988), of which it constitutes a minor revision the main purpose of which was to update the normative references clause.
14、BS ISO 3899:2005blank1Rubber Nitrile latex Determination of residual acrylonitrile content 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 i
15、s the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. CAUTION Certain procedures specified in this International Standard may involve the use or generation of substances, or the generation of waste, tha
16、t could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use. 1 Scope This International Standard specifies a method for the determination of the residual acrylonitrile content of nitrile rubber latices which have a re
17、sidual acrylonitrile content of less than 0,2 % (by mass). 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 (in
18、cluding any amendments) applies. ISO 123, Rubber latex Sampling ISO 1042, Laboratory glassware One-mark volumetric flasks 3 Principle A test portion of latex is distilled and the distillate collected in methanol. n-Dodecyl mercaptan is added to the distillate and the excess titrated with standard io
19、dine solution. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Silicone antifoaming agent, which does not affect the result of the determination. 4.2 Methanol. 4.3 Propan-2-ol. 4.4 Mercaptan solution, 1,25 %
20、 (by mass) n-dodecyl mercaptan solution in propan-2-ol. BS ISO 3899:20052 4.5 Potassium hydroxide, 6 % (by mass) solution in 95 % (by volume) ethanol. The ethanol shall be free from aldehydes. 4.6 Acetic acid, glacial. 4.7 Iodine, standard volumetric solution, c(l2) = 0,012 5 mol/dm3, freshly standa
21、rdized with a standard reference solution of sodium thiosulfate. 5 Apparatus Ordinary laboratory apparatus plus the following: 5.1 Distillation apparatus, consisting of a distillation flask of capacity 500 cm3, a still head, a vertical water-cooled condenser and a receiver of capacity 100 cm3with a
22、glass stopper through which pass a glass tube connected to the condenser and a shorter glass exit tube leading into a beaker of capacity 50 cm3. 5.2 One-mark volumetric flask, of capacity 100 cm3, conforming with the requirements of ISO 1042. 5.3 Conical flask, of capacity at least 250 cm3. 6 Sampli
23、ng Sampling shall be carried out in accordance with one of the methods specified in ISO 123. 7 Procedure 7.1 Determination Weigh 25 g 0,2 g of latex into the distillation flask (see 5.1) and add 100 cm3of water and 1 cm3of the silicone antifoaming agent (4.1). Place 25 cm3of methanol (4.2) in the re
24、ceiver and assemble the distillation apparatus so that the end of the tube connected to the condenser is immersed in the methanol. Put sufficient methanol (for example 10 cm3) in the beaker to cover the end of the exit tube. Immerse the receiver and beaker in ice. NOTE The purpose of the methanol in
25、 the beaker is to collect any acrylonitrile which is not trapped by the liquid in the receiver. Distil the mixture, adjusting the rate of boiling to control frothing, and collect 50 cm3of distillate in the receiver. Empty the contents of the receiver and beaker into the volumetric flask (5.2). Rinse
26、 through the condenser into the receiver twice with small (for example 5 cm3) portions of methanol and add the washings to the volumetric flask. Dilute to the mark with methanol. Pipette a 50 cm3aliquot portion of the diluted distillate into the conical flask (5.3) containing 25 cm3of propan-2-ol (4
27、.3). Pipette 10 cm3of mercaptan solution (4.4) into the flask. Add 1 cm3of potassium hydroxide solution (4.5) and allow to react for exactly 2 min at 23 C 2 C. Add 2 cm3of glacial acetic acid (4.6) to stop the reaction. The resulting pH should be between 4 and 6. Titrate with freshly standardized io
28、dine solution (4.7) to a yellow colour which persists for at least 60 s. Discard the iodine solution remaining in the burette, unless it is required for immediate use. BS ISO 3899:200537.2 Blank test Carry out a blank determination, following the procedure described in 7.1 but omitting the distillat
29、ion stage and using 500 cm3of a (1 + 1) methanol-water mixture. 8 Expression of results The residual acrylonitrile content is given, as a percentage by mass of the latex, by the formula ()0122100 1001000McVVVm ()01220 McV VmV= where M is the molar mass, in grams per mole, of acrylonitrile (= 53,06 g
30、/mol); c is the actual concentration, in moles of l2per cubic decimetre, of the iodine solution (4.7); V0is the volume, in cubic centimetres, of iodine solution used in the blank titration (see 7.2); V1is the volume, in cubic centimetres, of iodine solution used in the determination (see 7.1); V2is
31、the volume, in cubic centimetres, of the aliquot of diluted distillate taken (= 50 cm3); m is the mass, in grams, of the test portion (ca 25 g). If results of duplicate determinations do not agree to within 0,005 % (by mass), they shall be rejected and additional determinations carried out. 9 Precis
32、ion No precision data are currently available. 10 Test report The test report shall include the following particulars: a) a reference to this International Standard; b) the results, and the units in which they are expressed; c) the date of testing; d) any unusual features noted during the determinat
33、ion; e) details of any operation not included in this International Standard or in the International Standards to which reference is made, as well as any operation regarded as optional. BS ISO 3899:2005BS ISO BSI389 Chiswick High RoadLondonW4 4AL3899:2005BSI British Standards InstitutionBSI is the i
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