ISO 14932:2023

INTERNATIONAL ISO
STANDARD 14932
Second edition
2023-08
Rubber compounding ingredients —
Organic vulcanizing agents —
Determination of organic peroxide
content
Ingrédients de mélange du caoutchouc — Agents vulcanisants
organiques — Détermination de la teneur en peroxyde organique
Reference number
© ISO 2023
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General . 2
5 Titration method A for group a: Peroxyketals . 3
5.1 Purpose . 3
5.2 Principle . 3
5.3 General procedure . 3
5.4 Expression of results . . 3
5.4.1 Total amount of active oxygen . 3
5.4.2 Content . 4
6 Titration method B for group b: Diacyl peroxides . 5
6.1 Purpose . 5
6.2 Principle . 5
6.3 Measurement of active oxygen . 5
6.3.1 General procedure . 5
6.3.2 Calculation of amount of active oxygen . 5
6.3.3 Calculation of theoretical active oxygen . 6
6.4 Calculation of diacyl peroxide content . 6
7 Titration method C for group c: Diaralkyl and alkyl-aralkyl peroxides .7
7.1 Purpose . 7
7.2 Principle . 7
7.3 Reagents . 7
7.4 Apparatus . 8
7.5 Procedure . 8
7.5.1 Test sample analysis . 8
7.5.2 Blank test . 9
7.6 Expression of results . 9
7.6.1 Assay of aralkyl peroxide . 9
8 Determination of the assay of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane .9
8.1 Purpose . 9
8.2 Principle . 10
8.3 Gas chromatography method . 10
8.3.1 Using capillary column . 10
8.3.2 Using packed column .12
9 Precision .14
10 Test report .15
Annex A (informative) Method to determine the content of peroxyketal .16
Annex B (normative) Method to determine the content of tert-butyl hydroperoxide .19
Annex C (informative) Method to determine the content of diacyl peroxides .23
Annex D (normative) Pre-treatment of mixed sample with inorganic filler or uncured
rubber for the determination of peroxide content .25
Annex E (informative) Precision.27
Bibliography .31
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.
This second edition cancels and replaces the first edition (ISO 14932:2012), which has been technically
revised.
The main changes are as follows:
— gas chromatography using packed column has been added in 8.3;
— the solvent has been changed from chloroform to toluene and isopropyl alcohol;
— tetrahydrofuran has been removed due to toxicity;
— CAS Registry Numbers (CAS RN) have been added;
— Annex D and the former Annex E have been merged as Annex D;
— Formula (D.1) has been corrected.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
INTERNATIONAL STANDARD ISO 14932:2023(E)
Rubber compounding ingredients — Organic vulcanizing
agents — Determination of organic peroxide content
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
determine the applicability of any other restrictions.
1 Scope
This document specifies four methods for the determination of the content of the following groups of
organic peroxides used as rubber vulcanizing agents. There are three titration methods and one gas-
chromatography method.
a) titration method A for group a: Peroxyketals:
®1)
1,1-Di(tert-butylperoxy)cyclohexane (DTBPC; CAS Registry Number :3006-86-8)
1,1-Di(tert-butylperoxy)-2-methylcyclohexane (DBPMC; CAS RN 147217-40-1);
1,1-Di(tert-butylperoxy)-3,3,5-trimethylcylcohexane (DBPTC; CAS RN 6731-36-8);
2,2-Di(tert-butylperoxy)butane (DBPB; CAS RN 2167-23-9);
Butyl −4,4-di(tert-butylperoxy)valerate (BPV; CAS RN 995-33-5);
b) titration method B for group b: Diacyl peroxides:
Dibenzoyl peroxide (CAS RN 94-36-0);
Di(2,4-dichlorobenzoyl) peroxide (CAS RN 133-14-2);
Di(4-methylbenzoyl) peroxide (CAS RN 895-85-2);
c) titration method C for group c: Diaralkyl and alkyl-aralkyl peroxides:
Di(tert-butylperoxyisopropyl)benzene (CAS RN 2212-81-9);
Dicumyl peroxide (CAS RN 80-43-3);
tert-Butyl cumyl peroxide (CAS RN 3457-61-2);
d) gas-chromatography for dialkyl peroxides, using a capillary or packed column.
2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane (CAS RN 78-63-7)
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 385, Laboratory glassware — Burettes ®
1) Chemical Abstracts Service (CAS) Registry Number is a trademark of the American Chemical Society (ACS).
This information is given
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