1、BRITISH STANDARD BS 6057-3.21: 1996 ISO 3900:1995 Rubber latices Part 3: Methods of test Section 3.21 Determination of bound acrylonitrile content in nitrile latex ICS 83.040.10BS6057-3.21:1996 This British Standard, having been prepared under the directionof the Sector Board forMaterials and Chemic
2、als, waspublished under the authorityof the Standards Boardand comes into effect on 15July1996 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PRI/51 Draft for comment 94/306686 DC ISBN 0 580 26000 3 Committees responsible for this British Standard T
3、he preparation of this British Standard was entrusted to Technical Committee PRI/51, Latex, upon which the following bodies were represented: British Rubber Manufacturers Association Ltd. Malaysian Rubber Producers Research Association Medical Sterile Products Association Amendments issued since pub
4、lication Amd. No. Date CommentsBS6057-3.21:1996 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Sampling 1 7 Procedure 1 8 Expression of results 2 9 Test report 2 List of referenc
5、es Inside back coverBS6057-3.21:1996 ii BSI 12-1999 National foreword This Section of BS6057 has been prepared by Technical Committee PRI/51 and is identical with ISO3900:1995 Rubber Nitrile latex Determination of bound acrylonitrile content. It supersedes 7.1 of BS3397:1976 which is deleted by amen
6、dment. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication refer
7、red to Corresponding British Standard BS 6057 Rubber latices ISO 123:1985 Part 2:1987 Sampling (Identical) ISO 124:1992 Part 3 Methods of test Section 3.2:1992 Determination of total solids content of rubber latices (Identical) BS 7164 Chemical tests for raw and vulcanized rubber ISO 1407:1992 Part
8、3:1992 Methods for determination of solvent extract (Identical) ISO 1656:1996 Part 21:1996 Determination of nitrogen content (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 and 2, an inside back cover and a back cover. This standard h
9、as been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6057-3.21:1996 BSI 12-1999 1 WARNING Persons using this standard should be familiar with normal laboratory practice. This standard does not purport
10、 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. 1 Scope This International Standard specifies a method for the determin
11、ation of the bound acrylonitrile content of emulsion-polymerized NBR latices having a bound acrylonitrile content, expressed as a percentage of the polymer content, of between 18% and45%. The method is also applicable to, for example, carboxylic-nitrile-butadiene (XNBR) latices and nitrile-isoprene
12、(NIR) latices. NOTE 1The determination includes any water-insoluble nitrogen-containing additives present in the latex. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of public
13、ation, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IECandISO maintain registers
14、 of currently valid International Standards. ISO 123:1985, Rubber latex Sampling. ISO 124:, Latex, rubber Determination of total solids content 1) . ISO 1407:1992, Rubber Determination of solvent extract. ISO 1656:, Rubber, raw natural, and rubber latex, natural Determination of nitrogen content 2)
15、. 3 Principle A film is prepared from the latex and then extracted with water to remove water-soluble nitrogen-containing material, and finally dried to constant mass. The dry film is analysed by the method laid down in ISO1656. A known mass of the film is digested with a mixture of sulfuric acid, p
16、otassium sulfate and catalyst to convert the nitrogen present into ammonium hydrogen sulfate. The mixture is made alkaline and the liberated ammonia distilled and absorbed in a solution of boric acid. The bound acrylonitrile content is calculated from the volumes of standard volumetric solution requ
17、ired in the test and blank titrations. NOTE 2Some automatic analysers utilize the micro Dumas method to analyse for nitrogen; at present this is not published as an ISO method. It is also noted that, while automatic analysers generally have a high repeatability, there is often poor reproducibility b
18、etween instruments. 4 Reagents The reagents specified in ISO1656 for the semi-micro method shall be used, except that sulfuric acid (c =0,05mol/dm 3 ) shall be employed and sodium hydroxide (c =0,02mol/dm 3 ) is not required. 5 Apparatus 5.1 Mould, preferably of glass,1mm deep, and square-shaped wit
19、h approximately50-mm sides. 5.2 Extraction apparatus, in accordance with ISO1407. 5.3 Apparatus as specified in ISO1656 for the semi-micro method. 5.4 Oven, capable of being maintained at70 C 2 C. 5.5 Desiccator, capable of holding the mould (5.1). 6 Sampling Sampling shall be carried out in accorda
20、nce with one of the methods specified in ISO123. 7 Procedure If the total solids content of the latex is not known, determine it in accordance with ISO124. If the total solids content of the latex is greater than41% (m/m), dilute the latex with water to a solids content of40% (m/m) 1% (m/m). 1) To b
21、e published. (Revision of ISO 124:1992) 2) To be published. (Revision of ISO 1656:1988)BS6057-3.21:1996 2 BSI 12-1999 Pour the latex into the mould (5.1) placed on a perfectly horizontal surface, and scrape off the excess latex with a straightedge. Transfer the mould to the oven (5.4) and dry at70 C
22、 2 C for16h (i.e.over-night). NOTE 3At this stage, it is not essential that the film be totally dry, but it is necessary that it can be handled. Transfer the mould to the desiccator (5.5) and allow to cool. Demould the film and roll it (or a portion of it) in filter paper so that no part of the film
23、 is anywhere in contact with any other part of the film, and place the roll in the extraction cup of the extraction apparatus (5.2). Pour into the extraction flask sufficient water to fill the extraction cup two or three times. Assemble the extraction apparatus and reflux continuously for4h such tha
24、t each extraction takes15 min to30min. Remove the extracted film and dry it to constant mass in accordance with ISO124. Proceed in accordance with the method in ISO1656 for the semi-micro method, using100mg of the dried extracted film, weighed to the nearest0,5mg. Determine its nitrogen content, als
25、o carrying out the specified blank test, using boric acid solution to absorb the distilled ammonia, and sulfuric acid (c = 0,05 mol/dm 3 ) to titrate the distillate. Take the end-point of the titration as the colour change from bright green to grey. 8 Expression of results Calculate the bound acrylo
26、nitrile content, expressed as a percentage by mass of the dried extracted film, using the formula where 9 Test report The test report shall include the following particulars: a) a reference to this International Standard; b) all details necessary to identify the sample; c) the results, and the units
27、 in which they are expressed; d) 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; e) the date of the test. c is the actual concentration, expressed in moles per cubic decimetre, of t
28、he sulfuric acid solution used; V 1 is the volume, in cubic centimetres, of the sulfuric acid solution used in the titration of the distillate from the test portion; V 2 is the volume, in cubic centimetres, of the sulfuric acid solution used in the blank titration; m is the mass, in grams, of dried
29、extracted film used for the determination. 10,62cV 1 V 2 () m -BS6057-3.21:1996 BSI 12-1999 List of references See national foreword.BS 6057-3.21: 1996 ISO 3900:1995 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing
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