1、 STD.BSI BS EN IS0 L2b4-ENGL 1997 Lb24bbS Ob4093b 401 BRITISH STANDARD Plastics - Homopolymer and copolymer resins of vinyl chloride - Determination of pH of aqueous extract The European Standard EN EO 1264 : 1997 has the status of a British Standard ICs 83.080.20 BS EN IS0 1264 : 1997 BS 2782 : Par
2、t4: Method 454C : 1997 -o n-m U- NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPRIGET LAW u u - STD-BSI BS EN IS0 L2b4-ENGL 1777 M LbZibb7 Ob40737 348 been prepared under the direction of the Sector Board for Materiais and Chemicals, was published under the authority of the Standaids Bo
3、ard and comes into effect on 15 September 1997 hd. No. O BSI 1997 ISBN O 680 28504 9 BS EN IS0 1264 : 1997 Da Text affected National foreword This British Standard is the English language version of EN IS0 1264 : 1997. It is identical with IS0 1264 : 1980. It supersedes BS 2782 : Part 4 ; Method 454
4、C : 1978 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRIEM, Vinyl chloride, which has the responsibility to: - aid enquirem to understand the text; - present to the responsible intematio - monitor related international and European developments an
5、d promulgate them in the UK. A list of organizations represented on this commit b) 50 I 2 ml of sodium chloride solution. Stopper the flask and place it on the shaker (4.51. Agitate rapid- ly for 60 i 5 min. Allow the flask to stand for 5 to 10 min to allow the resin to settle (below or on the surfa
6、ce of the liquid). Then, using the pipette (4.2). transfer approximately 30 to 40 ml of the liquid above or below the resin into the beaker (4.3), which has been rinsed beforehand with the sodium chloride solution. (in cases where a large amount of foam has been formed, filtering may be necessary be
7、fore pipetting.) Measure the pH of the aqueous solution at a temperature of 23 f2 OC by means of the pH meter (4.1). Carry out two determinations. Express the values in pH units to one decimal place. If the difference in duplicate determinations is greater than 0,2 pH units, carry out a further seri
8、es of deter- minations until agreement within this limit is obtained. 1 EN IS0 1264 : 1997 6 Expression of results 7 Test report Calculate the arithmetic mean of the two values finally retained, rounding to the first decimal place, according to the usual rules. The test report shall include the foll
9、owing particulars : a) reference to this International Standard; b) complete identification of the product tested; ci the result expressed according to clause 6; d) any circumstances which may have affected the result. NOTE - Co-operative tests have shown reproducibility between dif- ferent laborato
10、ries, on the values of pH thus determined, of f 0,3. Annex Recommended method for the de-activation of glassware Immerse the glassware in a 100 g/l hydrochloric acid solution for 2 days. Replace the hydrochloric acid with a fresh solution and allow to stand for a further 2 days. Wash copiously with
11、de-ionized water four or five times. Wash with distilled water three times. Dry in an oven at 120 OC for 24 h. 2 BS EN IS0 1264 : 1997 BS 2782 : Part 4 : Method 454C : 1997 BSI 389 Chiswick High Road London w4 4AL STDOBSI BS EN IS0 12b4-ENGL 1777 = Lb24bb9 Ob110744 588 BSI - British Standards Instit
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