1、BRITISH STANDARD BS2782-4: Method433A: 1979 ISO4573:1978 Methods of testing Plastics Part4: Chemical properties Method433A: Determination of inorganic chlorine in epoxide resins and glycidyl esters ISO title: Epoxide resins and glycidyl esters Determination of inorganic chlorine IMPORTANT NOTE. Befo
2、re reading this method it is essential to read the foreword, general introduction and instructions to BS2782, published separately. UDC 678.5/.8:678.01:543.848:678.686BS2782-4:Method 433A:1979 This British Standard, having been prepared under the directionof the Plastics StandardsCommittee was publi
3、shed under the authority ofthe Executive Board and comesinto effect on 29June 1979 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference PLC/17 Draft for comment 77/50100 DC ISBN 0 580 10818 X National foreword This method, which has been prepared under th
4、e direction of the Plastics Standards Committee, is identical with ISO4573 “Plastics Epoxide resins and glycidyl esters Determination of inorganic chlorine”. Terminology and conventions. The text of the International Standard has been approved as suitable for publication, without deviation, as a Bri
5、tish Standard. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as t
6、he decimal marker. Wherever the words “International Standard” appear referring to this standard, they should be read as “British Standard”. Cross-reference. The technical committee has reviewed the provisions of ISO3696 to which reference is made in clause2 and has decided they they areacceptable f
7、or use in conjunction with this standard. A related BritishStandard is BS3978 “Water for laboratory use”. NOTETextual error. In the last line of paragraph2 of7.3 delete “deflection” and substitute “inflection”. WARNING NOTE. This method, which is identical with ISO4573, does not necessarily detail a
8、ll the precautions necessary to meet the requirements of theHealth and Safety at Work etc. Act1974. Attention should be paid to any appropriate safety precautions, and the method should be operated only by trained personnel. A British Standard does not purport to include all the necessary provisions
9、 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. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and2 and a back
10、cover. This standard has been updated (see copyright date) 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 issue CommentsBS2782-4:Method 433A:1979 BSI 10-1999 i Contents Page Natio
11、nal foreword Inside front cover 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Preparation of electrodes 1 7 Procedure 1 8 Expression of results 2 9 Test report 2ii blankBS2782-4:Method 433A:1979 BSI 10-1999 1 1 Scope and field of application This Interna
12、tional Standard specifies a direct potentiometric method for the determination of inorganic substances in epoxide resins and glycidylesters, called also “inorganic chlorine” or “ionic chlorine”. 2 Reference ISO 3696, Water for laboratory use Specifications 1) . 3 Principle Dissolution of a test port
13、ion in a suitable solvent. Determination of the chloride ion by potentiometric titration with a standard volumetric silver nitrate solution. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only grade1 water conforming to ISO3696. 4.1 Acetic acid, glacial, 1,05g/m
14、l. 4.2 Butanone (methyl ethyl ketone). NOTEIn some cases, butanone does not dissolve the resin; another, more suitable solvent should then be used, and mentioned in the test report. 4.3 Hydrochloric acid, 0,1N solution. 4.4 Potassium chloride, 0,01N solution. 4.5 Silver nitrate, 0,01N standard volum
15、etric solution. 4.5.1 Preparation Dissolve1,70g of silver nitrate in water and dilute to1litre. 4.5.2 Standardization Weigh, to the nearest0,1mg,20 to25mg of sodium chloride, previously dried at120 C. Transfer to a300ml conical flask, and dissolve in50ml of water. Titrate with the silver nitrate sol
16、ution (4.5.1) in accordance with7.3. 4.5.3 Calculation of concentration The concentration T, expressed as normality, is given by the formula where m is the mass, in milligrams, of sodium chloride used; V is the volume, in millilitres, of the silver nitrate solution (4.5.1) used in the titration. 5 A
17、pparatus Usual laboratory apparatus, and 5.1 Microburette, 10ml capacity, graduated in0,02ml; length of delivery tube approximately120mm. 5.2 Magnetic stirrer 5.3 pH-millivoltmeter, with glass and silver electrodes and titration stand. 6 Preparation of electrodes Before each titration, wash the glas
18、s electrode (see5.3) with the solvent (4.2), rinse with water, soak the electrode for at least10min in the hydrochloric acid (4.3), and rinse again with water and solvent. Polish the silver electrode before each titration with fine abrasive cloth (for example, grain coarseness P120 2) ) until a clea
19、n polished surface is obtained, and rinse with water. NOTE 1Observance of these instructions for preparing the electrodes is very important, as otherwise the electrodes will not respond properly during the titration. However, in practice when frequent measurements on the same type of product are mad
20、e, it is only necessary to prepare the electrodes daily. NOTE 2Other types of electrodes and other methods of preparing the electrodes can be used provided that there is agreement between participants. 7 Procedure 7.1 Weigh, to the nearest1mg, a test portion containing not more than1,42mg of inorgan
21、ic chlorine in a250ml beaker. Pipette100ml of the solvent(4.2) into the beaker and dissolve the test portion at room temperature, using the magnetic stirrer (5.2). 7.2 Add, by means of pipettes,1ml of the potassiumchloride solution (4.4) and25ml of theacetic acid (4.1) to the mixture. Titrate immedi
22、ately in accordance with7.3. 7.3 Place the electrodes and the microburette (5.1) containing the silver nitrate solution (4.5) in position, immersing the tip of the microburette about10mm in the liquid. Stir throughout the determination. Add the silver nitrate solution carefully and wait until a cons
23、tant potential has been established. 1) At present at the stage of draft. T m 58,45 V - = 2) Designation from EFPA Classification (European Federation of Producers of Abrasives).BS2782-4:Method433A:1979 2 BSI 10-1999 Record the microburette and meter readings and plot them rapidly as a graph. When t
24、he potential change is small for each increment of silver nitrate solution added, add volumes as large as0,1ml. When the rate of change of potential becomes greater than10mV per0,1ml, use0,05ml increments. Stop the titration about0,3ml after the deflection point. 7.4 Carry out a blank test at the sa
25、me time as the determination, following the same procedure but omitting the test portion. 8 Expression of results 8.1 Note the equivalence point from the graph prepared as described in 7.3. 8.2 The “inorganic chlorine” content C of the sample, expressed in milligrams per kilogram (parts per million
26、by mass) is given by the formula: where V 0is the volume, in millilitres, of the silver nitrate solution (4.5) used in the blank test (see7.4); V 1is the volume, in millilitres, of the silver nitrate solution (4.5) used in the titration of the test portion (see7.3); T is the normality of the silver
27、nitrate solution(4.5) calculated in accordance with4.5.3; m 0is the mass, in grams, of the test portion (see7.1). 9 Test report The test report shall include the following particulars: a) reference to this International Standard; b) the solvent used, if it is different from that indicated in4.2 (but
28、anone); c) the complete identification of the material tested; d) the type of electrode and the method of preparation used, if different from that specified in clause6; e) the test result and the method of expression used. C (V 1 V 0 ) 35,5T 1 000 m 0 - =blankBS2782-4: Method433A: 1979 ISO4573:1978
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