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1、BRITISH STANDARD BS 2782-4: Method 452C: 1979 Methods of testing Plastics Part 4: Chemical properties Method 452C: Determination of butyl rubber content of low density polyethylene compounds IMPORTANT NOTE. Before reading this method it is essential to read the foreword, general introduction and ins
2、tructions to BS 2782, issued separately. UDC 678.5/.8:678.01:678.742.2:543.86:678.742.4 BS 2782-4:Method 452C:1979 This British Standard, having been prepared under the direction of the Plastics Standards Committee, was published under the authority of the Executive Board and comes into effect on 29
3、 June 1979 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PLC/17 Draft for comment 78/52856 DC ISBN 0 580 10820 1 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible f
4、or 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 and a back cover. This standard has been updated (see copyright dat
5、e) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.Date of issueComments BS 2782-4:Method 452C:1979 BSI 12-1999i Contents Page 0Introduction1 1Scope1 2Reference1 3Principle1 4Apparatus1 5Re
6、agents1 6Procedure1 7Expression of results1 8Test report2 ii blank BS 2782-4:Method 452C:1979 BSI 12-19991 0 Introduction This method has been prepared under the direction of the Plastics Standards Committee. The method describes a procedure for determining the amount of butyl rubber in polyethylene
7、 compounds based on polymers of density not exceeding 0.930 g/cm3. Using this method any soluble substance other than butyl rubber will also be reported as butyl rubber but if the small proportion of extractable material normally in the polymer is known, allowance can be made for it. In any case, an
8、y result not exceeding 2 % may normally be taken as indicating freedom from butyl rubber. The method is technically similar to method 405C of BS 2782:1970 which will be withdrawn. WARNING NOTE. This British Standard method does not necessarily detail all precautions to meet the requirements of the H
9、ealth and Safety at Work etc. Act 1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. 1 Scope This method describes a procedure for determining the butyl rubber content of low density polyethylene compound. 2 Reference The
10、 following standards publication is referred to in this method. BS 2648, Performance requirements for electrically-heated laboratory drying ovens. 3 Principle The material is dissolved in hot light petroleum solvent and methyl ethyl ketone is added to precipitate the polyethylene. The mixture is all
11、owed to cool to room temperature, the polyethylene is filtered off, the extract is evaporated and the residue weighed. 4 Apparatus The following apparatus is required. 4.1 Beaker, 150 ml. 4.2 Water-bath 4.3 Filter flask and glass funnel 4.4 Evaporating basin, 150 ml. 4.5 Oven complying with the requ
12、irements of BS 2648 and capable of being controlled at 115 5 C. 5 Reagents The following reagents are required. 5.1 Methyl ethyl ketone 5.2 Light petroleum spirit, boiling range 80 C to 100 C. 6 Procedure Weigh into the beaker, to the nearest milligram, about 1 g of the sample in the form of small p
13、ieces or shavings. Add 30 ml of the petroleum spirit and warm on the water-bath until the sample is dissolved. Make up the solution to the original volume with the petroleum spirit. Stir the solution and warm it to the approximate temperature previously used for solution. Remove the beaker from the
14、water-bath and add rapidly with stirring 30 ml of the methyl ethyl ketone and then immediately 30 ml of a mixture of equal volumes of the petroleum spirit and the methyl ethyl ketone. Cover the beaker with a watch glass and allow to cool in a bath of cold water at a temperature of 23 2 C for 30 5 mi
15、n. Then filter the mixture through a 12.5 cm filter paper1) using a plain glass funnel fitted with a rubber bung into the filter flask using moderate suction. NOTETo maintain suction during filtration it is advisable to keep the filter fairly full of liquid so that the paper cone does not rise and l
16、ose contact with the walls of the funnel. Wash the beaker and the residue on the filter with 25 ml of the mixture of petroleum spirit and methyl ethyl ketone in approximately 5 ml portions. Do not permit the residue on the filter to dry during the filtration and ensure that the filtration is complet
17、e in 15 min to 20 min. Transfer the filtrate to the tared evaporating basin and wash the filter flask with 10 ml of the solvent mixture. Transfer this 10 ml of solvent mixture to the evaporating basin and evaporate the solvent on the water bath. Then place the basin in the oven at a temperature of 1
18、15 5 C for 45 min, cool in a desiccator and weigh. 7 Expression of results Calculate the butyl rubber content by the equation Butyl rubber content = where m1 is the mass (in grams) of the residue m2 is the mass (in grams) of the sample Express the result as the percentage by mass of butyl rubber in
19、the sample. 1) A Whatman No. 1 paper is suitable. 100 m1 m2 - - BS 2782-4:Method 452C:1979 2 BSI 12-1999 8 Test report The test report shall include the following particulars. a) A complete identification of the material tested including type, source, manufacturers code numbers, form, previous histo
20、ry, etc. b) A reference to this British Standard method, i.e. BS 2782:Method 452C:1979 c) The butyl rubber content of the material. blank BS 2782-4: Method 452C: 1979 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for prepa
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