ISO INTERNATIONAL STANDARD 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 manganese - Méthodes photométriques au periodate de sodium ISO Reference number ISO 7780:1998(E) by IHS under lic mitted without license from IHS Not for Resale ISO 7780:1998(E) Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO memberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughSOtechnical committees. Each member body interested in a subject for which a technical committee has been established has 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 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. @ISO1998 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic International OrganizationforStandardization Casepostale56·CH-1211Geneve20·Switzerland Internet [email protected] Printed in Switzerland Not for Resale @ISO ISO 7780:1998(E) Introduction always the possibility in the case of compounded 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 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 severe than is the case with natural rubber. Possibly for this reason, the determinationof manganese insyntheticrubbersandincompoundsbasedonsynthetic rubbersislessfrequently carried out; nevertheless, the methods specified in this International Standard are applicable to all the commonly used elastomers. order to obtain the manganese in soluble form; it is most suited to rubber compounds containing heavy loadings of method, referred to as the restricted method, is shorter and suitable for raw rubbers, their corresponding latices, and rubber 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: Determination of manganese content, may be used in place of could be useful before choosing the most desirable method for the determination of manganese in raw and vulcanized rubbers and latices. ii Not for Resale