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1、BRITISH STANDARD BS 7164-11.2: 1993 Chemical tests for raw and vulcanized rubber Part 11: Butadiene rubber Section 11.2 Method for determination of unsaturation Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI B
2、S 7164-11.2:1993 This British Standard, having been prepared under the direction of the Plastics and Rubber Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 May 1993 BSI 11-1999 The following BSI references relate to the work on this st
3、andard: Committee reference PRM/23 Draft for comment 91/43982 DC ISBN 0 580 20979 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical Committee PRM/23, upon which the foll
4、owing bodies were represented: Institute of Water and Environmental Management Laboratory of the Government Chemist Ministry of Defence Royal Society of Chemistry Rubber and Plastics Research Association Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank Univer
5、sity, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2:1993 BSI 11-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 3Principle1 4Reagents1 5Apparatus1 6Sampling1 7Preparation of test sample1 8Procedu
6、re1 9Calculation and expression of units2 10Repeatability2 11Test report2 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2:1993 ii BSI 11-1999 Foreword This Secti
7、on of BS 7164 has been prepared under the direction of the Plastics and Rubber Standards Policy Committee and supersedes 9.7 of BS 1673-9:1973, which will be deleted by amendment. BS 7164 rationalizes all the methods that deal with chemical analysis of raw, compounded and vulcanized rubber, some of
8、which have previously been published in BS 903, BS 1673 and BS 5923. Relevant Parts of those standards will be withdrawn or deleted by amendment, as appropriate, when superseded by Parts and Sections of BS 7164. This British Standard calls for the use of substances that may be injurious to health if
9、 adequate precautions are not taken. It refers only to technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are resp
10、onsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has
11、been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2:
12、1993 BSI 11-19991 1 Scope This Section of BS 7164 describes a method for the determination of unsaturation in raw polybutadiene rubber (BR) and butadiene based rubbers soluble in carbon tetrachloride. 2 References 2.1 Normative references This Section of BS 7164 incorporates, by reference, provision
13、s from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this Section of BS 7164 only when incorpo
14、rated in it by updating or revision. 2.2 Informative references This Section of BS 7164 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to
15、 the latest editions. 3 Principle Addition of iodine monochloride to the double bonds present in polybutadiene is carried out in carbon tetrachloride. The excess iodine monochloride liberates iodine from potassium iodide; the iodine is titrated with sodium thiosulfate. 4 Reagents WARNING. All recogn
16、ized health and safety precautions should be taken when performing this method of analysis. 4.1 General. Use only reagents of recognized analytical grade and any grade of water conforming to BS 3978:1987, or water of equivalent purity. 4.2 Extraction solvents. Ethanol toluene azeotrope (ETA), formed
17、 by mixing 7 volumes of ethanol with 3 volumes of toluene, refluxing for 1 h over freshly ignited quicklime and then distilling, collecting the fractions of constant boiling point. Alternatively the azeotrope may be prepared by mixing 7 volumes of absolute ethanol with 3 volumes of toluene. 4.3 Solv
18、ent. Carbon tetrachloride. 4.4 Iodine monochloride solution. Dissolve 30 g of iodine monochloride in 1 l of carbon tetrachloride. Store the solution in an amber coloured bottle. 4.5 Potassium iodide solution. Dissolve 75 g of potassium iodide in water and dilute to 500 ml. 4.6 Sodium thiosulfate sol
19、ution, freshly standardized. Standard volumetric solution, C(Na2S2O3) = 0.1 mol/dm3. 4.7 Starch solution. Dissolve sufficient starch in hot water to prepare a 1 % solution. 4.8 Iodine indicator powder NOTEThis is an alternative to starch solution. 5 Apparatus 5.1 General. Standard laboratory equipme
20、nt. 5.2 Balance, accurate to 0.1 mg. 5.3 Extraction apparatus, as described in BS 7164-3:1992. 5.4 Iodine flasks conforming to BS 2735:1987. 5.5 Sintered filters conforming to grade P4 of BS 1752:1983. 6 Sampling Sample raw rubber in accordance with BS 6315:1993. 7 Preparation of test sample Mill th
21、e test sample to as thin a sheet as possible. Extract the test sample in accordance with BS 7164-3:1992. Dry the test sample to constant weight within 1 mg. 8 Procedure 8.1 Test duplicate samples. Weigh, to the nearest 0.1 mg, a test sample of approximately 0.25 g. Place the test sample in an iodine
22、 flask (5.4) and add 50 cm3 of carbon tetrachloride and shake or allow to stand until dissolved. If a gel is found to be present, remove by filtration through a sintered filter (5.5). Carefully evaporate the filtrate to dryness in a weighed dish and dry to constant mass, to within 1 mg, under vacuum
23、 at 40 C. Determine the mass of the gel-free polymer, transfer to a clean iodine flask and redissolve in 50 cm3 of carbon tetrachloride. Add, from a burette, 50 cm3 of iodine monochloride solution (4.4) to the polymer solution, mix by swirling and place in darkness for (30 0.5) min at (23 2) C. Lice
24、nsed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2:1993 2 BSI 11-1999 Add 40 cm3 of potassium iodide solution (4.5), shake vigorously and titrate with sodium thiosulfate solution 0.1 mol/dm3 (4.6). Shake
25、thoroughly at intervals throughout the titration and after shaking wash the mixture from the stoppers and the neck of the flask down into the flask using a small quantity of distilled water. Continue the titration until the mixture has reached a straw colour, add a few drops of starch solution (4.7)
26、 and continue the titration to the end point, which is indicated by the disappearance of the blue colour. Alternatively, add 0.2 g to 0.5 g of an iodine indicator powder (4.8) to the polymer solution at the titration stage. Vigorously shake during the final stages of the titration to ensure that the
27、 liberated iodine is completely transferred to the aqueous phase. Ignore any reappearance of the blue colour more than 10 s after the end-point has been reached. 8.2 In parallel with the determination, carry out a blank test using the same quantities of reagents under the same operating conditions b
28、ut omitting the test sample. 9 Calculation and expression of units The percentage of unsaturated butadiene in the rubber is calculated by the formula: 10 Repeatability Duplicate samples shall agree to 0.5 % of the mean value obtained. 11 Test report The test report shall include the following inform
29、ation: a) reference to this British Standard; b) identification of the test sample; c) the mean of two results obtained; d) the date of the test. where V0is the volume in cubic centimetres of sodium thiosulfate solution used to titrate the reagent blank solution; Vis the volume in cubic centimetres
30、of sodium thiosulfate solution used to titrate the test solution; Cis the exact concentration, in moles per cubic decimetre, of sodium thiosulfate used; mis the mass, in grams, of the test sample. If the sample is filtered, m is the mass of the dried gel-free polymer; 2.7is a stoichiometric constant
31、. 2.7V0V() m - -C Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2:1993 BSI 11-1999 List of references Normative references BSI standards publications BRITISH STANDARDS INSTITUTION, London BS 1752:1
32、983, Specification for laboratory sintered or fritted filters including porosity grading. BS 2735:1987, Specification for iodine flasks. BS 3978:1987, Specification for water for laboratory use. BS 6315:1993, Methods of sampling of and further preparative procedures for raw natural and synthetic rub
33、ber. BS 7164, Chemical tests for raw and vulcanized rubber. BS 7164-3:1992, Methods for determination of solvent extract. Informative references BSI standards publications BRITISH STANDARDS INSTITUTION, London BS 903, Physical testing of rubber1). BS 1673, Methods of test for raw rubber and unvulcan
34、ized compounded rubber1). BS 5923, Methods for chemical analysis of rubber1). 1) Referred to in the foreword only. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:33:31 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7164-11.2: 1993 BSI 389 Chiswick High Road L
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