ISO 7270-1:2003

Rubber — Analysis by pyrolytic gas-chromatographic methods — Part 1: Identification of polymers (single polymers and polymer blends)

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.

Caoutchouc — Méthodes d'analyse par pyrolyse et chromatographie en phase gazeuse — Partie 1: Identification des polymères (un seul polymère ou un mélange de polymères)

General Information

• Status: Withdrawn
• Publication Date: 13-Apr-2003
• Withdrawal Date: 13-Apr-2003
• ICS: 83.060 - Rubber
• Technical Committee: ISO/TC 45/SC 2 - Testing and analysis
• Drafting Committee: ISO/TC 45/SC 2/WG 5 - Chemical tests
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 11-Feb-2020

Relations

• Revised: ISO 7270-1:2020 - Rubber — Analysis by pyrolytic gas-chromatographic methods — Part 1: Identification of polymers (single polymers and polymer blends)
• Effective Date: 23-Apr-2020
• Parent: ISO 7270-1:2003/Amd 1:2010 - Rubber — Analysis by pyrolytic gas-chromatographic methods — Part 1: Identification of polymers (single polymers and polymer blends) — Amendment 1
• Effective Date: 18-Dec-2008
• Revises: ISO 7270:1987 - Rubber — Identification of polymers (single polymers and blends) — Pyrolytic gas chromatographic method
• Effective Date: 15-Apr-2008
• Amended By: ISO 7270-1:2003/Amd 1:2010 - Rubber — Analysis by pyrolytic gas-chromatographic methods — Part 1: Identification of polymers (single polymers and polymer blends) — Amendment 1
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7270-1
First edition
2003-04-15

Rubber — Analysis by pyrolytic
gas-chromatographic methods —
Part 1:
Identification of polymers (single
polymers and polymer blends)
Caoutchouc — Méthodes d'analyse par pyrolyse et chromatographie en
phase gazeuse —
Partie 1: Identification des polymères (un seul polymère ou un mélange
de polymères)




Reference number
ISO 7270-1:2003(E)
©
ISO 2003

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ISO 7270-1:2003(E)
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ISO 7270-1:2003(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Principle . 1
4 Single polymers and blends . 2
5 Reagents . 3
6 Apparatus. 3
7 Procedure. 4
8 Interpretation of results. 5
9 Test report. 5
Table 1 — List of pyrograms contained in this part of ISO 7270 .6
Table 2 — Recommended operating conditions for micro-furnace pyrolysis followed by
chromatography with a capillary column . 7
Table 3 — Recommended operating conditions for Curie-point pyrolysis followed by
chromatography with a capillary column . 23
Table 4 — Recommended operating conditions for micro-furnace pyrolysis followed by
chromatography with a packed column . 36
Table 5 — Recommended operating conditions for Curie-point pyrolysis followed by
chromatography with a packed column . 42


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ISO 7270-1:2003(E)
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. 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
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7270 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 2, Testing and analyses.
This part of ISO 7270 cancels and replaces ISO 7270:1987, which has been technically revised.
ISO 7270 consists of the following parts, under the general title Rubber — Analysis by pyrolytic gas-
chromatographic methods:
 Part 1: Identification of polymers (single polymers and polymer blends)
 Part 2: Determination of styrene/butadiene/isoprene ratio
At the time of publication of this part of ISO 7270, Part 2 was in preparation.

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INTERNATIONAL STANDARD ISO 7270-1:2003(E)

Rubber — Analysis by pyrolytic gas-chromatographic
methods —
Part 1:
Identification of polymers (single polymers and polymer blends)
WARNING — Persons using this part of ISO 7270 should be familiar with normal laboratory practice.
This part of ISO 7270 does not purport to address all of 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
ensure compliance with any national regulatory conditions.
1 Scope
This part of ISO 7270 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. For details, see Clause 4. The method may be also
applicable to other types of polymer, but this must be verified by the analyst in each particular case.
NOTE The use of this part of ISO 7270 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.
2 Normative references
The following referenced documents are indispensable for the application 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 1407:1992, Rubber — Determination of solvent extract
ISO 1629:1995, Rubber and latices — Nomenclature
3 Principle
3.1 Raw or vulcanized rubbers and/or their blends are pyrolysed and the pyrolysis products are subjected
to gas-chromatographic analysis under predefined conditions. The chromatograms produced are referred to
as pyrograms.
3.2 Pyrograms are interpreted by comparison with reference pyrograms produced from the same rubbers
and/or blends, prepared and analysed under the same conditions.
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ISO 7270-1:2003(E)
4 Single polymers and blends
4.1 General
The rubbers in the following listing are grouped in accordance with ISO 1629.
4.2 Group M
a) Chlorinated polyethylene (CM) and chlorosulfonated polyethylene (CSM).
NOTE 1 The pyrogram will not differentiate between these chlorinated polyethylenes.
b) Ethylene-propylene copolymers (EPMs) and ethylene-propylene-diene terpolymers (EPDMs).
NOTE 2 The pyrogram can differentiate terpolymers from copolymers when the pyrogram indicates characteristic
“diene” monomer pyrolysis products.
c) Acrylic rubbers (ACMs).
4.3 Group O
Epichlorohydrin rubbers [homopolymer (CO), copolymer (ECO) and terpolymers].
NOTE The pyrogram will not differentiate betwen these various types of epichlorohydrin polymer.
4.4 Group Q
Polysiloxanes.
4.5 Group R
a) Polybutadiene (BR).
NOTE 1 The pyrogram will not differentiate between polymers containing different proportions of isomers.
b) Polychloroprene (CR).
NOTE 2 The pyrogram will not differentiate between the various types of polychloroprene rubber, or polychloroprene
rubber from other types of chlorinated rubber.
c) Isobutene-isoprene copolymer (IIR).
NOTE 3 The pyrogram will not differentiate butyl rubber from its halogenated forms or from isobutene.
d) Polyisoprene (NR or IR).
NOTE 4 The pyrogram will not differentiate natural from synthetic polyisoprenes.
e) Acrylonitrile-butadiene copolymer (NBR).
NOTE 5 In some cases, NBR can be differentiated from hydrogenated acrylonitrile-butadiene copolymer (HNBR). The
pyrogram will not differentiate a single NBR from an NBR/BR blend or a blend of various types of NBR.
f) Styrene-butadiene copolymer (SBR).
NOTE 6 In some cases, block polymers can be differentiated from random polymers. The pyrogram will not
differentiate a single SBR from an SBR/BR blend or a blend of various types of SBR.
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ISO 7270-1:2003(E)
4.6 Blends
With the exception of blends containing both styrene-butadiene copolymer and polybutadiene, the method
enables blends of the following polymers to be identified:
a) polyisoprene (NR or IR);
b) polybutadiene (BR);
c) isobutene-isoprene copolymers (IIRs);
d) styrene-butadiene copolymers (SBRs).
5 Reagents
All reagents shall be of analytical grade.
5.1 Solvents for extraction purposes
The following solvents are suitable (see 7.2):
5.1.1 Acetone.
5.1.2 Methanol.
5.1.3 Methyl ethyl ketone.
5.2 Carrier gas
5.2.1 Nitrogen.
5.2.2 Helium.
5.3 Gas for flame-ionization detector: hydrogen plus purified compressed air.
6 Apparatus
6.1 Extraction apparatus
As specified in ISO 1407.
6.2 Pyrolysis/chromatography system
6.2.1 General
The apparatus utilized to obtain pyrograms consists of four parts: the pyrolysis device, the gas chromatograph,
the gas-chromatographic column and the data-handling equipment.
6.2.2 Pyrolysis device
The following types of electrically heated pyrolysis device are suitable:
6.2.1.1 Micro-furnace, with quartz tubes in which the test portion is pyrolysed.
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ISO 7270-1:2003(E)
6.2.1.2 Curie-point pyrolyser, with a holder (pyrolysis probe) containing ferromagnetic material which
surrounds the test portion and is heated to the Curie-point temperature to pyrolyse the test portion.
6.2.1.3 Platinum-filament pyrolyser, with a holder (pyrolysis probe) containing a platinum filament
which surrounds the test portion and is heated to pyrolyse the test portion.
6.2.3 Gas chromatograph
A wide variety of chromatographs using either a flame-ionization detector (FID) or a thermal conductivity
detector (TCD) are suitable for use in this part of ISO 7270.
Selective detectors such as ECD (electron capture detector), FPD (flame photometric detector), FTD (flame
thermionic detector), AED (atomic emission detector) can give useful information. For identification of
pyrolysis products, a mass spectrometer detector can be utilized.
6.2.4 Chromatographic columns
A variety of column lengths and diameters and stationary and liquid phases are suitable for use in this part of
ISO 7270, the main requirement being good resolution of the volatile pyrolysis products.
NOTE 1 Capillary columns with good separation efficiency are suitable, but not essential.
NOTE 2 Capillary columns containing non-polar polydimethylsiloxanes and partially modified (diphenyl-,
cyanopropylphenyl- or other) semi-polar silicones are suitable.
NOTE 3 Usually, capillary columns require little evaluation, while it often is necessary to evaluate many conditions for
polar and non-polar packed columns.
The conditions chosen will depend on the column used. Typical operating conditions for the gas
chromatograph with both polar and non-polar columns can be found in Tables 1 to 5. Typical pyrograms
obtained can be found in Figures 1 to 44.
6.2.5 Data-handling equipment
A recorder, an integrator or a computer data-analysis system may be used.
7 Procedure
7.1 Accurate comparison of the pyrogram of an unknown polymer with the reference is only possible under
the same conditions.
7.2 Extraction of test samples is recommended to remove additives which may interfere with the
chromatographic separation. For oil-extended materials, extraction of the extender oil is essential otherwise
this oil may cause serious interference in the pyrogram. Carry out the extraction following the general
principles of either method A or method B in ISO 1407:1992. The chosen solvent shall not affect the polymer
and shall remove as much of the additives as possible. After extraction, dry the test sample, as residual
solvent may cause interference with the pyrolysis products (see 8.4).
7.3 Take a test portion of mass appropriate to the apparatus used. Generally, this will be between 0,1 mg to
5 mg. For good reproducibility, the size of the test portion should be as small as practicable.
7.4 Place the test portion in the pyrolysis device and pyrolyse. An appropriate pyrolysis temperature is
400 °C to 800 °C for a micro-furnace or Curie-point pyrolyser, and 800 °C to 1 200 °C for a platinum-filament
pyrolyser.
7.5 Record the pyrogram for comparison with the pyrogram of a known polymer or polymer blend obtained
under the same conditions.
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ISO 7270-1:2003(E)
8 Interpretation of results
8.1 Each polymer will be characterized by the retention times of its main peaks. Some polymers produce
characteristic hydrocarbons and their identification is relatively easy. Examples
...