BS-EN-ISO-119-1998.pdf
BRITISH STANDARD BS EN ISO 119:1998 Implementing Amendment No. 1 to BS 2782-4: Method 451E: 1978/ISO 119:1977 (renumbers the BS as BS EN ISO 119:1998), not published separately Plastics Phenol-formaldehyde mouldings Determination of free phenols Iodometric method (ISO 119:1977) ICS 83.140.99 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 119:1998 © BSI 05-1999 ISBN 0 580 10171 1 Foreword This British Standard is technically identical to International Standard ISO 119:1977 Plastics Phenol-formaldehyde mouldings Determination of free phenols Iodometric method. In 1998 the European Committee for Standardization (CEN) accepted ISO 119:1977 as European Standard EN ISO 119:1998. 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. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN ISO title page, pages 2 to 4, an inside back cover and a back 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.DateComments 10255October 1998Implementing European Standard Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 119:1998 © BSI 05-1999i Contents Page ForewordInside front cover Foreword2 Text of EN ISO 1193 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN ISO 119 July 1998 ICS 83.080.10 Descriptors: See ISO document English version Plastics Phenol-formaldehyde mouldings Determination of free phenols Iodometric method (ISO 119:1977) Plastiques Pièces moulées à base de phénoplastes Dosage des phénols libres Méthode iodométrique (ISO 119:1977) Kunststoffe Phenoplast-Formteile Bestimmung der freiem Phenole Iodometrisches Verfahren (ISO 119:1977) This European Standard was approved by CEN on 12 June 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref. No. EN ISO 119:1998 E Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 119:1998 © BSI 05-1999 2 Foreword The text of the International Standard from Technical Committee ISO/TC 61, Plastics, of the International Organization for Standardization (ISO) has been taken over as a European Standard by Technical Committee CEN/TC 249, Plastics, the Secretariat of which is held by IBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 1999, and conflicting national standards shall be withdrawn at the latest by January 1999. According to CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard ISO 119:1977 has been approved by CEN as a European Standard without any modification. Contents Page Foreword2 1Scope and field of application3 2References3 3Principle3 4Reagents3 5Apparatus3 6Preparation of test sample3 7Procedure3 8Expression of results4 9Test report4 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 119:1998 © BSI 05-19993 1 Scope and field of application This International Standard specifies an iodometric method for the semi-quantitative determination of the amount of free phenols in phenol-formaldehyde mouldings. NOTEThis International Standard does not provide an absolute measure of the free phenols present. The amount of free phenols in a moulded article is influenced to a major extent by the degree of cure. Its evaluation is also of interest where the possibility of contamination of foodstuffs or other materials in contact with the article has to be considered. 2 References ISO/R 385, Burettes. ISO 565, Test sieves Woven metal wire cloth and perforated plate Nominal sizes of apertures. ISO 648, Laboratory glassware One-mark pipettes1). 3 Principle Hot aqueous extraction of free phenols from a powdered test portion. Iodination of the aqueous extract by a solution of iodine in the presence of sodium tetraborate. Acidification, then immediate titration of the excess iodine with standard volumetric sodium thiosulphate solution, using a starch solution as indicator. Calculation of the result assuming the reaction of six atoms of iodine with each molecule of phenol. 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity. 4.1 Sodium tetraborate, decahydrate (Na2B4O7.10H2O). 4.2 Sulphuric acid, 2 N solution. 4.3 Iodine, about 0,05 N solution. Dissolve 6,35 g of iodine in approximately 40 ml of a 500 g/l solution of potassium iodide and dilute to 1 000 ml with water. 4.4 Sodium thiosulphate, 0,05 N standard volumetric solution. 4.5 Starch, approximately 2,5 g/l solution. 5 Apparatus Ordinary laboratory apparatus and 5.1 Means for reducing the mouldings to a powder. 5.2 Sieve, with nominal apertures of 250 Èm, complying with the requirements of ISO 565. 5.3 Balance, accurate to 0,01 g. 5.4 Glass-stoppered flask, 250 ml capacity. 5.5 Glass-stoppered iodine flask, 250 ml capacity. 5.6 Sintered glass crucible, or filter funnel with sintered disk, of pore size 40 to 90 Èm. Alternatively a filter funnel with hardened medium speed filter paper may be used. 5.7 Pipettes, capacities 5 and 10 ml, complying with the requirements of ISO 648. 5.8 Burette, complying with the requirements of ISO/R 385. 6 Preparation of test sample Reduce a fully representative sample of the mouldings to powder by filing, milling, grinding, turning or drilling, taking care that no undue heating of the material occurs. Sieve the powder thus obtained, using the sieve (5.2), and use for the test that portion passing through the sieve. Keep the sample in a tightly stoppered flask until required. The extraction with water (see 7.3) shall begin within 1 h of grinding the moulding. NOTEThe method of reduction to powder can affect the results. In cases of dispute, or for referee purposes, the method should be agreed between the interested parties. 7 Procedure 7.1 Test portion Weigh, to the nearest 0,01 g, 5 ± 0,1 g of the sieved material (see clause 6). 7.2 Blank test Carry out a blank test by replacing the 5 ml of aqueous extract (7.3) with 5 ml of water and proceeding exactly as described in 7.4. 7.3 Preparation of the test solution Place the test portion (7.1) in the flask (5.4) and cover it with ten times its mass of water at a temperature of 90 to 100 °C. Stopper the flask and shake it so that the powder is thoroughly wetted. Allow it to cool at room temperature, for 1 h, with occasional shaking. Then filter the contents of the flask through the sintered glass crucible or filter funnel (5.6). 1) At present at the stage of draft. (Revision of ISO/R 648.) Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 119:1998 4 © BSI 05-1999 7.4 Determination Transfer, with a pipette (5.7), 5 ml of the filtered extract, corresponding to 0,5 g of the powder, to the iodine flask (5.5). Add 10 ml of the iodine solution (4.3) and 3 to 4 g of the sodium tetraborate (4.1), and dilute to about 100 ml with water. Immediately stopper the flask. Allow the mixture to stand for 10 min, and then add 20 to 30 ml of the sulphuric acid solution (4.2). Immediately titrate the liberated iodine with the sodium thiosulphate solution (4.4), adding 2 ml of the starch solution (4.5) as indicator near the end-point of the titration and continuing until the blue starch/iodine colour has disappeared. A residual pale colour from the mouldings may be present at the end of the titration. 8 Expression of results The free phenols content, expressed as a percentage by mass of phenol (C6H5OH), is given by the formula where V1 is the volume, in millilitres, of the sodium thiosulphate solution (4.4) used in the blank test (7.2); V2 is the volume, in millilitres, of the sodium thiosulphate solution (4.4) used for the determination (7.4); T is the normality of the sodium thiosulphate solution (4.4); 0,0157 is the mass, in grams, of phenol corresponding to 1 ml of exactly 1 N sodium thiosulphate solution; 0,5 is the mass, in grams, of the powdered sample corresponding to 5 ml of filtered extract (see 7.4). If T = 0,05 N, the formula for calculation of free phenols content reduces to 0,157 (V1 V2) 9 Test report The test report shall include the following particulars: a) reference to this International Standard; b) full details necessary for the identification of the sample; c) the method used for reducing the mouldings to powder; d) amount of free phenols; e) date of the test. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI © BSI 05-1999 BS EN ISO 119:1998 Publications referred to See national foreword Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:09:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 119:1998 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. 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