BS-ISO-7780-1998 BS-7164-26.2-1998.pdf
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1、BRITISH STANDARD BS ISO 7780:1998 BS 7164-26.2: 1998 Rubber and rubber lattices Determination of manganese content Sodium periodate photometric methods ICS 83.040.10 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 7780:1998 This Briti
2、sh Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 October 1998 BSI 04-1999 ISBN 0 580 30358 6 National foreword This British Standard reproduces verbatim ISO 7780
3、:1998 and implements it as the UK national standard. It supersedes BS 7164-26.2:1990 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/23, Chemical testing of rubber, which has the responsibility to: aid enquirers to understand the text; present to
4、the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtai
5、ned on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” fa
6、cility of the BSI Standards Electronic Catalogue. 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 obli
7、gations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, page ii, pages 1 to 7 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 ta
8、ble on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 7780:1998 BSI 04-1999i Contents Page National forewordInside front cover Forewordii Introduction1
9、1Scope1 2Normative references1 3General method (for samples not affected by heavy loadings of fillers2 4Restricted method (limited to samples with filler loadings 10 %)4 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy:
10、 sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 7780:1998 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) is
11、 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 represen
12、ted 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
13、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 produc
14、ts. This second edition cancels and replaces the first edition (ISO 7780:1987) which has been technically revised. Descriptors: Rubber, latex, determination of content, manganese, spectrophotometric analysis. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 07:29:45 GMT+00:00 2006, Uncontrolle
15、d Copy, (c) BSI BS ISO 7780:1998 BSI 04-19991 Introduction Manganese in certain forms is known to catalyse the oxidative breakdown 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 prese
16、nt, even in relatively large amounts, without degradation taking place. However, there is 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. Clearl
17、y, 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 inf
18、luence 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 determination of manganese in synthetic rubbers and in compounds based on synthetic rubbers is le
19、ss frequently carried out; nevertheless, the methods specified in this International Standard are applicable to all the commonly used 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
20、. 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 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 s
21、econd 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
22、 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 ISO 7780. Both standards should be consulted because there may be some background material in each which could be
23、 useful before choosing the most desirable method for the determination of manganese in raw and vulcanized rubbers and latices. 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,
24、if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. 1 Scope This International Standard specifies photometric methods for the determination of manganese, after oxi
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