ISO/TC 45/SC 2/WG 5 - Chemical tests

This document specifies a method of thermal analysis of vulcanized rubber by differential scanning calorimetry (DSC). This method is intended for the observation and measurement of various properties and phenomena associated, such as physical transitions (glass transition, melting and crystallization, polymorphic transitions, etc.).

This document specifies an instrumental (automatic analyser) method for the determination of total sulfur in rubber and rubber products.

This document describes two methods for identification of antidegradants (antioxidants, antiozonants and stabilizers) which can be present in raw rubber, unvulcanized compounded rubber, or rubber products, by thin layer chromatography. Method A is a simplified method that provides for the identification of known materials and can be used to check the presence or absence of a particular antidegradant which is expected to be present. Method B is a more detailed method that enables a greater degree of separation of the spots to be obtained and therefore can be used to detect and identify an unknown antidegradant. Antidegradants to which these methods are applicable include phosphited polyalkyl phenols, substituted bisphenols, secondary amines, substituted cresols and substituted p-phenylenediamines. Examination for other types of antidegradants is possible under the same condition when there is a standard chromatogram.

This document specifies an atomic absorption spectrometric method for the determination of the manganese content of rubbers. The method is applicable to raw rubber and rubber products having manganese content above 0,5 ppm. Manganese contents below this limit can be determined, provided that suitable adjustments are made either to the mass of the test portion or to the concentrations of the solutions used, or both. The use of the standard additions method can lower the bottom limit of detection.

This document specifies an atomic absorption spectrometric method for the determination of the copper content of rubbers. The method is applicable to raw rubber and rubber products having copper contents above 1 ppm. Copper contents below this limit can be determined, provided that suitable adjustments are made to either the mass of the test portion or to the concentrations of the solutions used, or both. The use of the standard additions method can lower the bottom limit of detection.

This document specifies a quantitative test method to determine the 2-mercaptobenzothiazole content in rubber and rubber products by high performance liquid chromatography (HPLC). This document delivers a method for quantifying 2-mercaptobenzothiazole in rubber products for a better selection of curing conditions. This document provides a method to follow the curing of rubber with sulfur- and benzothiazole-based accelerators using a chemical measurement which is complementary to the classical rheometric technique.

This document specifies a method for the determination of the total sulfur content of raw rubber and unvulcanized or vulcanized rubber compounds by ion chromatography following the preparation of a sample solution using either a tubular furnace combustion or an oxygen combustion flask method. The tubular furnace combustion method is applicable for rubbers with sulfur content less than 0,1 % as it is possible that the oxygen combustion flask method will not give sufficiently accurate results. The oxygen combustion flask method is not applicable to rubbers containing a metal salt that forms an insoluble metal sulfate, such as barium sulfate (CAS 7727‑43‑7).

This document describes the method of determination of both major and trace levels of metal contents in rubber — raw, vulcanized — by ICP-OES.

This document describes a procedure for the determination of the following antidegradants in vulcanized rubbers: — aminoketone group; — naphthylamine group; — diphenylamine group; — p-phenylenediamine; — monophenol group. The groups of antidegradants are summarized in Table A.1 with the chemical names, the abbreviated terms and the CAS registry numbers. Extender oils, when present, can interfere. For poly-2,2,4-trimethyl-1,2-dihydroquinoline, the method provides only an approximation because of its polymeric nature.

This document specifies a method for the identification of polymers, or blends of polymers, in raw rubbers and in vulcanized or unvulcanized compounds from pyrograms (pyrolysis-gas chromatographic patterns) obtained under the same conditions. This allows qualitative identification of single rubbers or blends, with exceptions discussed below. This document is not intended for quantitative analysis. The method applies first and foremost to single polymers. When the pyrogram indicates a characteristic hydrocarbon, the method is also applicable to blends. For details, see Clause 5. The method can be also applicable to other types of polymer when verified by the analyst in each particular case. NOTE The use of this document pre-supposes sufficient working knowledge of the principles and techniques of gas chromatography to enable the analyst to carry out the operations described and to interpret the results correctly.

This document provides a qualitative method for the identification of rubbers by their pyrolysis products using tandem gas-chromatography/mass spectrometry. The method applies to rubbers in the raw state and to unvulcanized and vulcanized compounds. Compounds can be based on a single rubber or a blend of two or more rubbers. Where the level of a particular rubber in a blend is A non-restrictive list of rubbers is given in Clause 4.

This document specifies methods for the determination of chlorine and/or bromine present in raw rubber as well as vulcanized or unvulcanized rubber compounds. The methods are applicable to natural rubbers and to the following synthetic rubbers: isoprene, styrene-butadiene, butadiene, butyl, halogenated butyl, nitrile, ethylene-propylene, chloroprene and epichlorohydrin.

This document specifies an atomic absorption spectrometric method for the determination of the lead content of rubbers. The method is applicable to raw rubber and rubber products. There is no limit to the concentration of lead that can be determined. High or low concentrations can be determined, provided that suitable adjustments are made to the mass of the test portion and/or the concentration of the solutions used. The use of the standard-additions method might lower the bottom limit of detection.

This document specifies an atomic absorption spectrometric method for the determination of the zinc content of rubbers. The method is applicable to raw rubber and rubber products having zinc contents at a minimum of 0,05 % (mass fraction). Zinc contents below this limit can be determined, provided that suitable adjustments are made to the mass of the test portion and/or to the concentrations of the solutions used. The use of the standard additions method might lower the bottom limit of detection.

This document specifies a method of preparing samples from vulcanized rubber for use in chemical tests.

This document specifies an atomic absorption spectrometric method for the determination of the magnesium content of natural rubber latex concentrate, raw natural rubber and products made from natural rubber.

This document specifies an atomic absorption spectrometric method for the determination of the iron content of rubbers. The method is applicable to raw rubber, rubber products and latex having iron contents of 5 mg/kg to 1 000 mg/kg. Higher concentrations can be determined, provided that suitable adjustments are made to the mass of the test portion and/or the concentrations of the solution used.

This document specifies three methods for the determination of ash from raw rubbers, compounded rubbers and vulcanizates. The methods are applicable to raw, compounded or vulcanized rubbers of the M, N, O, R and U families described in ISO 1629, except that: — Method A is not used for the determination of ash from compounded or vulcanized rubbers containing chlorine, bromine or iodine; — Method B is used for compounded or vulcanized rubbers containing chlorine, bromine or iodine. It shall not be used for uncompounded rubbers; — Method C is intended to be used for the determination of ash from raw, compounded or vulcanized rubber not containing chlorine, bromine or iodine by wrapping the test portion in ashless filter paper; — Lithium and fluorine compounds might react with silica crucibles to form volatile compounds, giving low ash results. Platinum crucibles shall therefore be used for ashing fluorine-containing and lithium-polymerized rubbers. This document does not cover the interpretation of the ash results as to the inorganic chemical content of a compound or vulcanizate. This is the responsibility of the analyst, who has to be aware of the behaviour of rubber additives at elevated temperatures.

This document specifies two methods for the determination of ash from raw rubbers, compounded rubbers and vulcanizates using a thermogravimetric analyser (TGA). The methods are applicable to raw, compounded or vulcanized rubbers of the M, O, R and U families described in ISO 1629: — Method A is applicable for the determination of the ash from raw rubbers. — Method B is applicable for the determination of the ash from compounded or vulcanized rubbers. The methods are not applicable for the determination of the ash from raw rubbers, compounded or vulcanized rubbers containing chlorine, bromine or iodine. This document does not cover the interpretation of the ash results from the inorganic chemical contents of compounded or vulcanized rubbers.

ISO 20463:2018 specifies the measuring methods of the combustion energy (i.e. gross calorific value) and the carbon dioxide emission amount from biobased and non-biobased materials in rubber or rubber products. ISO 20463:2018 applies to rubber and rubber products (including polyurethane) such as raw materials, materials and final products.

ISO 10638:2017 specifies a method using gas chromatography/mass spectrometry, for the identification of antidegradants in raw rubbers, latices, unvulcanized-rubber compounds and vulcanized-rubber products. It is applicable to the 31 types of antidegradant listed in Annex A. The method specified is qualitative and is not intended for quantitative analysis.

ISO 9924-2:2016 specifies a thermogravimetric method for the determination of the total organic content, carbon black content, carbonaceous residue and ash in vulcanizates and uncured compounds containing polymers which form a carbonaceous residue on pyrolysis (see 1.2). The loss in mass at around 300 °C is an approximate guide to the volatile-matter content of the compound. The method is suitable for the analysis of rubber compounds and vulcanizates containing the hydrocarbon polymers covered by ISO 9924‑1 plus the following copolymers with polar groups which form a carbonaceous residue on pyrolysis: a) acrylonitrile-butadiene copolymers (NBRs); b) carboxylated acrylonitrile-butadiene copolymers (XNBRs); c) hydrogenated acrylonitrile-butadiene copolymers (HNBRs); d) chlorinated isobutylene-isoprene copolymers (CIIRs); e) brominated isobutylene-isoprene copolymers (BIIRs).

ISO/TS 17796: 2013 specifies a qualitative method of thermodesorption ? gas chromatography ? mass spectrometry (TD-GC-MS) for the identification of volatile components in rubber fumes, after trapping on a solid sorbent based on 2,6-diphenylphenylene-oxide polymer resin. It is applicable to a screening of emissions from the processing of rubber compounds in the ambient workplace and storage environment.

ISO 4650:2012 specifies two methods for the identification of rubbers, including thermoplastic elastomers, either in the raw state or in the form of vulcanized or unvulcanized mixes. The first method is based on infrared spectrometric examination using the transmission technique. The second method makes use of analysis by reflectance. A comparison of the spectra resulting from reflectance (attenuated total reflectance, ATR) and transmission (film) is given. Both methods comprise examination of polymers by their pyrolysis products (pyrolysates), or by films cast from solution or obtained by moulding (for raw rubbers only). Typical spectra are given. The methods specified are qualitative methods only.

ISO 7270-2:2012 specifies a pyrolytic gas-chromatographic method for the determination of the styrene/butadiene/isoprene ratio in copolymers, or blends of homopolymers and/or copolymers, in raw rubbers or in unvulcanized or vulcanized compounds. It is applicable to copolymers/terpolymers consisting of styrene, butadiene and isoprene, and blends of these polymers.

ISO 9924-3:2009 specifies a thermogravimetric method for the determination of the main constituents of rubber compounds such as elastomer(s), carbon black and mineral filler. It establishes the “fingerprint” of the tested material. However, the result does not always correspond exactly to the theoretical formula of the rubber. This method applies to raw or compounded rubbers, vulcanized and unvulcanized, after preliminary extraction. This method applies to rubbers with hydrocarbon backbones (NR, BR, SBR, IIR, EPDM, ACM, AEM, etc.) used alone or as mixtures. For the mixtures, the polymer content corresponds to the total rubber, and it is not usually possible to identify individual polymers. This method applies to rubbers with halogenated hydrocarbon backbones (CR, CSM, FKM, CM, CO, ECO, etc.) or containing nitrogen (NBR, HNBR, NBR/PVC, etc.), as well as to their mixtures. However, these rubbers often form carbonaceous residues which interfere with the analysis. Application of an appropriate procedure minimizes these interferences. This method also applies to rubbers with a polysiloxane backbone (VMQ, etc.) and to rubbers not listed above.

ISO 9028:2006 specifies methods for disintegration of raw rubber and rubber products by nitric acid or by a mixture of nitric and sulfuric acids. This International Standard is generally applicable, but is essential where potentially volatile elements or combinations of elements are present (i.e. As, Sb, Bi, and Zn + Cl, Cu + Cl and Pb + Cl). It is useful in these cases because lower temperatures are involved which result in less loss by volatilization. These methods will be used in order to produce solutions for the determination of metals, for example as traces, if the application of ISO 247, Rubber - Determination of ash, is not advisable. These methods prevent loss of volatile metal derivatives and the formation of insoluble metal silicates (which may result during dry ashing of halogenated rubbers containing zinc or of rubbers filled with silica).

This International Standard specifies an instrumental (automatic analyser) method for the determination of total nitrogen in rubber and rubber additives.

Describes a pyrolytic method (A) and two chemical degradation methods (B and C) for the determination of the carbon black content of artificial rubber and copolymers. Replaces the second edition, of which it constitutes a minor revision.

ISO 9924-1:2016 specifies a thermogravimetric method for the determination of the total organic content, carbon black content and ash in vulcanizates and uncured compounds. The loss in mass at 300 °C is an approximate guide to the volatile-matter content of the compound. The method is suitable for the analysis of rubber compounds and vulcanizates containing the following rubbers occurring alone or as mixtures: a) polyisoprene of natural or synthetic origin; b) polybutadiene; c) styrene-butadiene copolymers; d) isobutylene-isoprene copolymers; e) ethylene-propylene copolymers and related terpolymers. NOTE The field of application of the method may be extended to the analysis of compounds containing rubbers different from those given in this subclause, provided that the applicability of the method is tested beforehand using known compounds or vulcanizates having a similar composition. Other compounds are covered in ISO 9924‑2. The method is not suitable for rubbers containing polymers which form a carbonaceous residue during pyrolysis, such as many chlorine- or nitrogen-containing rubbers. The method is also not suitable for materials containing additives which cause the formation of carbonaceous residues during pyrolysis, such as cobalt and lead salts or phenolic resins. The method is not suitable for compounds containing mineral fillers, such as carbonates or hydrated aluminium oxides, which decompose in the temperature range from 25 °C to 650 °C, unless suitable corrections based on prior knowledge of filler behaviour can be made. The method is not suitable for the determination of the total polymer content of compounds or vulcanizates containing non-rubber organic ingredients that cannot be completely removed by solvent extraction carried out in accordance with ISO 1407.

ISO 6101-3:2014 specifies an atomic absorption spectrometric method for the determination of the copper content of rubbers. The method is applicable to raw rubber and rubber products having copper contents above 1 ppm. Copper contents below this limit can be determined, provided that suitable adjustments are made to the mass of the test portion and/or to the concentrations of the solutions used. The use of the standard additions method can lower the bottom limit of detection.

ISO 6101-4:2014 specifies an atomic absorption spectrometric method for the determination of the manganese content of rubbers. The method is applicable to raw rubber and rubber products having manganese content above 0,5 ppm. Manganese contents below this limit can be determined, provided that suitable adjustments are made to the mass of the test portion and/or to the concentrations of the solutions used. The use of the standard additions method might lower the bottom limit of detection.

ISO 17257:2013 provides a qualitative method for the identification of rubbers by their pyrolysis products using tandem the gas-chromatography/mass spectrometry. The method applies to rubbers in the raw state and to unvulcanized and vulcanized compounds. Compounds can be based on a single rubber or a blend of two or more rubbers. Where the level of a particular rubber in a blend is

ISO 1407:2011 specifies four methods for the quantitative determination of the material extractable from raw rubbers, both natural and synthetic; two of the methods are also applicable to the unvulcanized and vulcanized compounds of raw rubbers. Method A measures the mass of the solvent extract, after evaporation of the solvent, relative to the mass of the original test portion. Method B measures the difference in the mass of the test portion before and after extraction. Method C, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction using boiling solvent. Method D, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction relative to the mass of the original test portion. Recommendations as to the solvent most appropriate for each type of rubber are given in an annex.

ISO 6101-6:2011 specifies an atomic absorption spectrometric method for the determination of the magnesium content of natural rubber latex concentrate, raw natural rubber and products made from natural rubber.

ISO 10638:2010 specifies a qualitative method, using gas chromatography/mass spectrometry, for the identification of antidegradants in raw rubbers, latices, unvulcanized-rubber compounds and vulcanized-rubber products. It is applicable to 31 types of antidegradant. Users should note that the method specified is a qualitative one and is not intended for quantitative analysis.

ISO 16565:2008 specifies the methods to be used to determine the content of 5‑ethylidenenorbornene (ENB) or dicyclopentadiene (DCPD) in ethylene-propylene-diene (EPDM) terpolymers in the 0,1 % to 15 % range. ENB and DCPD are dienes introduced into ethylene-propylene rubbers to generate specific cure properties. Since high precision for diene content determination is important, a Fourier transform infrared spectroscopic (FT‑IR) method is utilized. NOTE The procedures for mass fraction of ENB and mass fraction of DCPD differ only in the location in the infrared (IR) peak being quantified.

ISO 6101-5:2006 specifies an atomic absorption spectrometric method for the determination of the iron content of rubbers. It is applicable to raw rubber, rubber products and latex having iron contents of 5,0 mg/kg to 1 000 mg/kg. Higher concentrations may be determined, provided that suitable adjustments are made to the mass of the test portion and/or the concentrations of the solution used.

ISO 5478:2006 specifies a method for the determination of the styrene content of all types of styrene-butadiene rubber (SBR), including oil-extended types. The method is applicable to styrene-butadiene rubbers reinforced with styrene homopolymer, to give the total styrene content. The method is also applicable for determining the styrene in block copolymers containing up to 50 % (by mass) of styrene. It is applicable to vulcanizates of mixtures of SBR with other polymers (NR, BR, IR and CR) and is considered a method for estimating the SBR content of mixtures, if the styrene content of the SBR is known and provided that no other styrene-containing materials are present. Any other non-extractable aromatic material which absorbs in the specified spectral region will interfere with this method. The procedure may give low results when the content of mineral fillers insoluble in nitric acid exceeds 5 % (by mass).

ISO 247:2006 specifies two methods for the determination of ash from raw rubbers, compounded rubbers and vulcanizates. The methods are applicable to raw, compounded or vulcanized rubbers of the M, N, O, R and U families described in ISO 1629, except that: Method A is not intended to be used for the determination of ash from compounded or vulcanized rubbers containing chlorine, bromine or iodine. Method B is intended to be used for compounded or vulcanized rubbers containing chlorine, bromine or iodine. lt is not intended to be used for uncompounded rubbers.

ISO 4650:2005 specifies a method for the identification of rubbers, including thermoplastic elastomers, either in the raw state or in the form of vulcanized or unvulcanized mixes. The method is based on infrared spectrometric examination using the transmission technique. The method comprises examination of polymers by their pyrolysis products (pyrolysates), or by films cast from solution or obtained by moulding (for raw rubbers only). Typical spectra are given.

ISO 248:2005 specifies two methods, a hot-mill method and an oven method, for the determination of moisture and other volatile-matter content in raw rubbers. These methods are applicable to the determination of the volatile-matter content in the R-group of rubbers listed in ISO 1629 which are rubbers having an unsaturated carbon chain, for example, natural rubber and synthetic rubbers derived at least partly from diolefins. ISO 248:2005 may also be applicable to other rubbers, but in these cases it is necessary to prove that the change in mass is due solely to loss of original volatile matter and not to rubber degradation. The hot-mill method is not applicable to natural and synthetic isoprene rubbers or to rubbers too difficult to handle on a hot mill or to rubbers in powdered or chip form.

ISO 7270-1:2005 specifies the principles and procedures for determining, by pyrolysis and subsequent gas chromatography, the styrene (STY)/butadiene (BD)/isoprene (IP) ratio in copolymers, or blends of homopolymers and/or copolymers, in raw rubbers or vulcanized or unvulcanized compounds. It is applicable to copolymers/terpolymers consisting of styrene, butadiene and isoprene, and blends of these polymers.

ISO 7270-1:2003 specifies a method for the identification of polymers, or blends of polymers, in raw rubbers and in vulcanized or unvulcanized compounds from pyrograms (pyrolysis-gas chromatographic patterns) obtained under the same conditions. This allows qualitative identification of single rubbers or blends, with exceptions discussed below. This part of ISO 7270 is not intended for quantitative analysis. The method applies first and foremost to single polymers. When the pyrogram indicates a characteristic hydrocarbon, the method is also applicable to blends. The method may be also applicable to other types of polymer, but this must be verified by the analyst in each particular case.

This International Standard specifies an instrumental (automatic analyser) method for the determination of total sulfur in rubber and rubber additives.