ISO-3451-4-1998.pdf

A Reference number ISO 3451-4:1998(E) INTERNATIONAL STANDARD ISO 3451-4 Second edition 1998-12-15 Plastics Determination of ash Part 4: Polyamides Plastiques Détermination du taux de cendres Partie 4: Polyamides ISO 3451-4:1998(E) © ISO 1998 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genève 20 Switzerland Internetisoiso.ch Printed in Switzerland ii Contents 1 Scope1 2 Normative reference1 3 Principle1 3.1 Unfilled materials1 3.2 Filled and glass-fibre reinforced materials 1 3.3 Flame-retardant materials reinforced with glass fibre2 4 Reagents (method C or method A in the presence of DBB).2 5 Apparatus.2 6 Procedure.2 6.1 Test portion.2 6.2 Unfilled materials3 6.3 Filled and glass-fibre reinforced materials 3 6.4 Materials reinforced with glass fibre containing flame-retardant antimony trioxide and/or other volatilizable additives.3 7 Expression of results 4 8 Precision.4 9 Test report4 © ISOISO 3451-4:1998(E) iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 3451-4 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical properties. This second edition cancels and replaces the first edition (ISO 3451-4:1986), which has been technically revised. ISO 3451 consists of the following parts, under the general title Plastics Determination of ash: Part 1: General methods Part 2: Poly(alkylene terephthalate) materials Part 3: Unplasticized cellulose acetate Part 4: Polyamides Part 5: Poly(vinyl chloride) INTERNATIONAL STANDARD © ISOISO 3451-4:1998(E) 1 Plastics Determination of ash Part 4: Polyamides WARNING This part of ISO 3451 may involve hazardous chemicals, materials and operations. This part of ISO 3451 does not purport to address the safety problems associated with its use. It is the responsibility of the user to establish proper safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 3451 specifies methods for determination of the ash of polyamides, both filled and unfilled. The general procedures given in ISO 3451-1 are followed. For unfilled materials method A or method C of ISO 3451-1:1997 is used. For filled and glass-fibre reinforced materials method A of ISO 3451-1:1997 is used. For glass-fibre filled materials containing flame retardant, antimony trioxide, and/or other, volatilizable, additives such as pigment zinc sulfide, a modification is incorporated to remove these as volatile bromine component(s). 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO 3451. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of ISO 3451 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3451-1:1997, Plastics Determination of ash Part 1: General methods. 3 Principle 3.1 Unfilled materials Direct calcination by burning the organic matter and treating the residue at a high temperature until constant mass is reached (ISO 3451-1:1997, method A). If the material contains metal halides and/or metals (especially in the presence of halogenated material) which are liable to evaporate during burning of the organic matter, calcination after sulfation can be applied (ISO 3451-1:1997, method C). This procedure is carried out by heating the organic matter together with concentrated sulfuric acid up to a temperature where fuming and subsequent burning of the organic matter occurs, and finally treating the residue at a high temperature until constant mass is reached. 3.2 Filled and glass-fibre reinforced materials Direct calcination, by burning the organic matter and treating the residue at a high temperature until constant mass is reached (ISO 3451-1:1997, method A) (see note 1 in 3.3). ISO 3451-4:1998(E) © ISO 2 3.3 Flame-retardant materials reinforced with glass fibre Calcination by burning the organic matter in the presence of decabromobiphenyl (DBB) and finally treating the residue at a high temperature until constant mass is reached (ISO 3451-1:1997, method A). NOTE 1Some additives, for instance zinc sulfide, are also completely volatilized as bromides by burning the organic matter in contact with decabromobiphenyl (DBB). Information with respect to the additive(s) present in the material and the potential to evaporate during burning in contact with DBB should be requested from the supplier or obtained by testing on the pure chemical. NOTE 2Flame retardants with a high bromine content, for instance ethylene bis(tetrabromophthalimide) or brominated polystyrene may also be used. The applicability and amount of chemical to be used can be determined by carrying out ash determinations in accordance with 6.4 with increasing amounts of flame retardant until a constant result is obtained. The chemical should be applied as a powder. 4 Reagents (method C or method A in the presence of DBB) During the analysis, use only reagents of analytical grade or specified grade and only distilled water or water of equivalent purity. 4.1 Ammonium carbonate, anhydrous. 4.2 Ammonium nitrate, approximately 10 % (m/m) solution. 4.3 Sulfuric acid, r 1,84 g/ml. 4.4 Decabromobiphenyl (DBB), powder, technical grade or higher purity. WARNING The use of decabromobiphenyl may result in the formation of dioxins. Temperatures in the order of 600 ° °C to 850 ° °C are generally known as ideal temperatures for the formation of dioxins. 5 Apparatus Apparatus specified in clause 4 of ISO 3451-1:1997, and in particular: 5.1 Crucibles of silica, porcelain or platinum, inert to the material tested, and typically of diameter (upper part) 50 mm to 60 mm and height equal to the diameter (see note 2 in 3.3). 5.2 Muffle furnace, capable of being maintained at (600 ± 25) °C, (850 ± 50) °C or at a minimum temperature of 850 °C. 5.3 Fume cupboard. 6 Procedure The material shall be in the form of small pieces of 1 cm ¥ 0,5 cm ¥ 0,2 cm or smaller, granules or powder. Filled or reinforced materials shall be dried before calcination, i.e. by heating at 100 °C until constant mass is reached. 6.1 Test portion Take a quantity of the test sample sufficient to yield 5 mg to 200 mg of ash (see table 1). In the case of reinforced materials, take a test portion of 2 g or more. If the likely quantity of ash is unknown, carry out a preliminary ash determination. According to the approximate ash content, choose the size of the test portion to be used from table 1. © ISOISO 3451-4:1998(E) 3 Table 1 Mass of test portion Approximate ashTest portionMass of ash obtained %gmg 2005 to 10 . 0,01 to 0,0510010 to 50 . 0,05 to 0,15025 to 50 . 0,1 to 0,22525 to 50 . 0,2 to 11020 to 100 . 1 to 10550 to 500 . 102 200 6.2 Unfilled materials Follow the procedure described in ISO 3451-1:1997, method A, applying a calcination temperature of (850 ± 50) °C. If the material contains metal halides or metals in the presence of halogenated material, liable to evaporate during the calcination procedure, or in those cases where “sulfated ash” is required, method C shall be applied (ISO 3451-1:1997, method C). 6.3 Filled and glass-fibre reinforced materials Follow the procedure described in ISO 3451-1:1997, method A, applying a calcination temperature of (850 ± 50) °C. If at that temperature glass fibres present become molten and thus prevent further calcination of the polymer, lower the temperature of calcination to (600 ± 25) °C and repeat the procedure with a fresh test portion. 6.4 Materials reinforced with glass fibre containing flame-retardant antimony trioxide and/or other volatilizable additives The sample shall be ground or cut to pieces of 1 cm ¥ 0,5 cm ¥ 0,2 cm or smaller. Proceed as in 5.3.1 and 5.3.2 of ISO 3451-1:1997, method A. Add to the sample a quantity of DBB (4.4) equal to half the mass of the sample in grams and mix well in the crucible. Place the crucible in the muffle furnace, applying a calcination temperature of at least 850 °C. The muffle furnace shall be placed in a fume cupboard. Continue as directed in ISO 3451-1:1997, from 5.3.4 of method A. Directly placing the crucible into the muffle furnace is preferred. If direct calcination leads to large differences between repeated tests, for instance due to loss of ash-containing material, gently heat the crucible over a quiet flame until formation of fumes ceases. Make sure that the volatile components are properly drawn off by a fume cupboard. Place the crucible in the muffle furnace and apply a calcination temperature of at least 850 °C. Continue as directed in ISO 3451-1:1997, from 5.3.4 of method A. Glass-fibre crucibles provided with two glass-fibre discs may also be used. The crucible shall be prepared by heating it in the muffle furnace at the test temperature and cooling it in a desiccator until constant mass is reached. Introduce the sample between the glass-fibre discs into the crucible. Place the crucible in the muffle furnace for 30 min. Allow the crucible to cool in a desiccator for 20 min. For unground material the residue in the crucible shall be calcinated a second time according to the procedure described in 6.4. The amount of DBB added to the residue shall be 1 g. ISO 3451-4:1998(E) © ISO 4 7 Expression of results The ash or sulfated ash, expressed as a percentage by mass, is given by the formula m m 1 0 100× where m0is the mass, in grams, of test portion; m1is the mass, in grams, of ash obtained. Calculate the average of two results and round off to the nearest 0,1 %. 8 Precision Precision data of the ash determination are described in clause 8 of 3451-1:1997, with the exception of the DBB method described in 6.4. The precision data were determined with eight laboratories and eight materials. For glass-fibre reinforced polyamides (PA/glass), the precision data given in table 2 were obtained. Table 2 Precision data for PA/glass Material/FillerMean ash % srsRrR PA/glass33,160,2720,2820,7600,790 where sris the repeatability standard deviation; sRis the reproducibility standard deviation; ris the repeatability value, comprising the value below which the absolute difference between two single test results obtained under repeatability conditions (same operator, same apparatus, same laboratory and within a short interval of time) may be expected to lie with a probability of 95 %; Ris the reproducibility value, comprising the value below which the absolute difference between two single test results obtained under reproducibility conditions (different operator, different apparatus, different laboratories) may be expected to lie with a probability of 95 %. The precision of the direct calcination of glass-fibre-containing materials and the DBB method is not known because inter-laboratory data are not available. However, the precision of these methods is expected not to deviate significantly from the known data. Inter-laboratory data are being gathered and will be added at the next revision. 9 Test report The test report shall include the following information: a) a reference to this part of ISO 3451; b) all details necessary for identification of the material tested; including type, manufacturer's code number, source, trade name, etc.; c) the method of calcination used; d) the temperature used for calcination; -,-,- © ISOISO 3451-4:1998(E) 5 e) the treatment of the sample prior to the test, if any; f) the individual results of the two determinations and the average for the ash or sulfated ash obtained; g) the mass of test portion used. ISO 3451-4:1998(E) © ISO ICS 83.080.20 Descriptors: plastics, polyamides, analysis methods, combustion analysis, ash determination. Price based on 5 pages