ISO-7780-1998.pdf
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1、A Reference number ISO 7780:1998(E) INTERNATIONAL STANDARD ISO 7780 Second edition 1998-08-01 Rubber and rubber latices Determination of manganese content Sodium periodate photometric methods Caoutchoucs et latex de caoutchouc Dosage du manganse Mthodes photomtriques au periodate de sodium Copyright
2、 International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:38:18 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 7780:1998(E) ISO 1998 All rights reserved. Unless ot
3、herwise 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 Genve 20
4、Switzerland Internetisoiso.ch Printed in Switzerland ii 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
5、. 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 Intern
6、ational 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 bo
7、dies casting a vote. International Standard ISO 7780 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products. This second edition cancels and replaces the first edition (ISO 7780:1987) which has been technically revised. Copyright International Organization for Standardization Prov
8、ided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:38:18 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 7780:1998(E) iii Introduction Manganese in certain forms is known to catalyse the oxidative breakdown
9、 of natural rubber, although the mechanism by which degradation is brought about is not fully understood. It is recognized also that other forms of manganese can be present, even in relatively large amounts, without degradation taking place. However, there is always the possibility in the case of co
10、mpounded rubbers that, under the influence of some constituents of the compound (notably the unsaturated acids), the manganese could assume a more aggressive role. Clearly, it would be an advantage to distinguish analytically between catalytically active and inactive forms, but no generally accepted
11、 method has yet been put forward for doing so. There is therefore no alternative to determining the total amount of manganese in the rubber. Little is known about the influence of manganese on the catalytic oxidation of synthetic rubbers, although it is widely accepted that its effect may be less se
12、vere than is the case with natural rubber. Possibly for this reason, the determination of manganese in synthetic rubbers and in compounds based on synthetic rubbers is less frequently carried out; nevertheless, the methods specified in this International Standard are applicable to all the commonly u
13、sed elastomers. The first of the two specified methods, referred to as the general method, is believed to be applicable to all rubbers and compounded rubbers in all forms. In this method, the ash from the rubber is taken through a fusion stage in order to obtain the manganese in soluble form; it is
14、most suited to rubber compounds containing heavy loadings of inert fillers such as clay, or materials which form insoluble phosphates, for example titanium dioxide. The second method, referred to as the restricted method, is shorter and suitable for raw rubbers, their corresponding latices, and rubb
15、er compounds not containing a heavy loading of the fillers referred to above. It is expected that the second method would be used more frequently. For those equipped with atomic absorption equipment, ISO 6101-4:1997, Rubber Determination of metal content by atomic absorption spectrometry Part 4: Det
16、ermination of manganese content, may be used in place of ISO 7780. Both standards should be consulted because there may be some background material in each which could be useful before choosing the most desirable method for the determination of manganese in raw and vulcanized rubbers and latices. Co
17、pyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:38:18 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standard
18、ization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:38:18 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISOISO 7780:1998(E) 1 Rubber and rubber latices Determination of manganes
19、e content Sodium periodate photometric methods WARNING Persons using this International Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establis
20、h appropriate safety and health practices and to ensure compliance with any national regulatory conditions. 1Scope This International Standard specifies photometric methods for the determination of manganese, after oxidation with sodium periodate, in rubbers and rubber latices. Both methods contain
21、provisions for analysis of chlorine-containing rubber. Clause 3 specifies a method for compounded or vulcanized rubbers which is not affected by heavy loadings of fillers such as synthetic and natural silicates or calcium carbonates in various forms, or by the presence of compounding ingredients whi
22、ch form an insoluble phosphate under the conditions of the test. Clause 4 specifies a method for raw and compounded natural and synthetic rubbers and latices which do not contain heavy loadings (more than about 10 %) of inert silicate fillers or any ingredient such as titanium dioxide which under th
23、e conditions of test will form an insoluble phosphate. 2Normative references The following standards contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subje
24、ct to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 123:1), Rubber
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