ISO 21561-1:2015
(Main)Styrene-butadiene rubber (SBR) — Determination of the microstructure of solution-polymerized SBR — Part 1: 1H-NMR and IR with cast-film method
Styrene-butadiene rubber (SBR) — Determination of the microstructure of solution-polymerized SBR — Part 1: 1H-NMR and IR with cast-film method
ISO 21561-1:2015 specifies procedures for the quantitative determination of the microstructure of the butadiene and the content of styrene in solution-polymerized SBR (S-SBR) by 1H-NMR spectrometry as an absolute method and by IR spectrometry as a relative method. The styrene content is expressed in mass % relative to the whole polymer. The trans, cis and vinyl contents are expressed in mol % relative to the butadiene. These methods are applicable only for raw rubber. NOTE 1 IR spectrometry can also give absolute values of microstructure by calibration with S-SBRs of known absolute microstructure obtained by 1H-NMR spectrometry. NOTE 2 Only "vinyl", "trans" and "cis" are used in this part of ISO 21561. However, the expression of vinyl, trans and cis mean as follows in general: - vinyl: vinyl unit, vinyl bond, 1,2-unit, 1,2-bond, 1,2-vinyl-unit or 1,2-vinyl-bond; - trans: 1,4-trans unit, 1,4-trans bond, trans-1,4 unit or trans1,4 bond; - cis: 1,4-cis unit, 1,4-cis bond, cis-1,4 unit or cis-1,4 bond.
Caoutchouc styrène-butadiène (SBR) — Détermination de la microstructure du SBR polymérisé en solution — Partie 1: Méthode 1H-NMR et IR avec film moulé
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21561-1
First edition
2015-07-15
Styrene-butadiene rubber (SBR) —
Determination of the microstructure
of solution-polymerized SBR —
Part 1:
1
H-NMR and IR with cast-film method
Caoutchouc styrène-butadiène (SBR) — Détermination de la
microstructure du SBR polymérisé en solution —
1
Partie 1: Méthode H-NMR et IR avec film moulé
Reference number
ISO 21561-1:2015(E)
©
ISO 2015
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ISO 21561-1:2015(E)
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ii © ISO 2015 – All rights reserved
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ISO 21561-1:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 NMR method (absolute method) . 1
3.1 Principle . 1
3.2 Reagents. 2
3.3 Apparatus . 2
3.4 Sampling . 2
3.5 Procedure . 2
3.6 Determination of the microstructure . 3
4 IR method (relative method) . 4
4.1 Principle . 4
4.2 Reagents. 4
4.3 Apparatus . 4
4.4 Sampling . 5
4.5 Procedure . 5
4.5.1 Preparation of sample solution . 5
4.5.2 Preparation of film coating . 5
4.5.3 Measurement of IR spectrum . 5
4.6 Determination of microstructure . 6
4.6.1 Measurement of absorbance corresponding to each microstructure component. 6
4.6.2 Calculation . 7
4.7 Conversion of the IR method results to absolute results . 8
5 Precision . 9
6 Test report . 9
Annex A (informative) Procedure for sample-film preparation and measurement of
microstructure by FTIR spectrophotometry .10
Annex B (informative) Precision .15
Bibliography .17
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ISO 21561-1:2015(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 45, Rubber and rubber products, Subcommittee
SC 2, Testing and analyses.
This first edition of ISO 21561-1, together with ISO 21561-2, cancels and replaces ISO 21561:2005, which
has been technically and nominally revised with the following changes:
— the descriptions of D’s were modified in 4.6.2;
— some terms and expressions were revised to be aligned with those in the ISO 21561-2 to be (ATR
method);
— it also incorporates the Amendment, ISO 21561:2005/Amd 1:2010.
ISO 21561 consists of the following parts, under the general title Styrene-butadiene rubber (SBR):
1
— Part 1: H-NMR and IR with cast-film method
— Part 2: FTIR with ATR method
iv © ISO 2015 – All rights reserved
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INTERNATIONAL STANDARD ISO 21561-1:2015(E)
Styrene-butadiene rubber (SBR) — Determination of the
microstructure of solution-polymerized SBR —
Part 1:
1
H-NMR and IR with cast-film method
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This International Standard 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 ensure compliance with any national regulatory conditions.
CAUTION — Certain procedures specified in this International Standard may involve the use or
generation of substances, or the generation of waste, that could constitute a local environmental
hazard. Reference should be made to appropriate documentation on safe handling and disposal
after use.
1 Scope
This part of ISO 21561 specifies procedures for the quantitative determination of the microstructure of
1
the butadiene and the content of styrene in solution-polymerized SBR (S-SBR) by H-NMR spectrometry
as an absolute method and by IR spectrometry as a relative method. The styrene content is expressed in
mass % relative to the whole polymer. The trans, cis and vinyl contents are expressed in mol % relative
to the butadiene. These methods are applicable only for raw rubber.
NOTE 1 IR spectrometry can also give absolute values of microstructure by calibration with S-SBRs of known
1
absolute microstructure obtained by H-NMR spectrometry.
NOTE 2 Only “vinyl”, “trans” and “cis” are used in this part of ISO 21561. However, the expression of vinyl,
trans and cis mean as follows in general:
— vinyl: vinyl unit, vinyl bond, 1,2-unit, 1,2-bond, 1,2-vinyl-unit or 1,2-vinyl-bond;
— trans: 1,4-trans unit, 1,4-trans bond, trans-1,4 unit or trans1,4 bond;
— cis: 1,4-cis unit, 1,4-cis bond, cis-1,4 unit or cis-1,4 bond.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 1407, Rubber — Determination of solvent extract
ISO 1795, Rubber, raw natural and raw synthetic — Sampling and further preparative procedures
3 NMR method (absolute method)
3.1 Principle
3.1.1 A small quantity of an extracted S-SBR is dissolved in deuterated chloroform.
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ISO 21561-1:2015(E)
1
3.1.2 A H-NMR spectrum of the sample solution is measured at a 15 ppm sweep width.
1
With the peak areas obtained from H-NMR, calculate the microstructure of the butadiene portion and
the styrene content by the theoretical formulae.
3.2 Reagents
3.2.1 Deuterated chloroform, CDCl , containing 0,03 % of tetramethyl silane (TMS) as internal
3
standard. The purity of the CDCl itself shall be >99,8 %.
3
3.2.2 Ethanol-toluene azeotrope (ETA).
3.2.3 Acetone.
3.3 Apparatus
1
3.3.1 H-NMR spectrometer, Fourier transform nuclear magnetic resonance (FT-NMR) spectrometer
with a resonance frequency of 150 MHz or higher.
3.3.2 Extraction apparatus, as described in ISO 1407.
3.3.3 Vacuum oven, operated at 50 °C to 60 °C.
3.3.4 Analytical balance, accurate to 0,1 mg.
3.4 Sampling
The raw rubber shall be sampled in accordance with ISO 1795.
3.5 Procedure
3.5.1 Extract rubber additives such as extender oil and antioxidants in accordance with ISO 1407,
using ETA or acetone as the extraction solvent. Dry the extracted S-SBR under vacuum in the oven at
50 °C to 60 °C.
3.5.2 Take 15 mg to 50 mg of the extracted S-SBR and dissolve it completely in 0,5 ml of deuterated
chloroform (3.2.1). The concentration of this sample solution shall be selected according to the resolution
of the spectrometer used.
1
3.5.3 Measure the H-NMR spectrum of the S-SBR solution and a solvent blank [deuterated chloroform
(3.2.1)] under the following conditions:
Mode single-pulse mode
Measurement temperature room temperature to 50 °C
No. of data points 32 k
Offset 5 ppm
Sweep width 15 ppm or wider
Flip angle 30° pulse
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ISO 21561-1:2015(E)
Pulse repetition 4 s to 30 s
Accumulation 32 times to 256 times
3.6 Determination of the microstructure
1
3.6.1 Integrate the signal intensities of the H-NMR spectrum over each of the areas A, B and C defined
1
in Table 1. Figure 1 gives an example of a H-NMR spectrum showing the areas A, B and C.
Table 1 — Definition of signal integration areas
Area Signal integration range
A From 4,3 ppm to minimum intensity point around 5,0 ppm
From minimum intensity point around 5,0 ppm to minimum intensity
B
point around 6,1 ppm
C From minimum intensity point around 6,1 ppm to 7,7 ppm
TMS Integrated signal intensity of TMS in CDCl containing TMS
blank 3
CD From 6,1 ppm to 7,7 ppm in CDCl containing TMS
blank 3
TMS Integrated signal intensity of TMS in S-SBR sample solution
B
C
A
X 8 6 4 2 0
Key
X shift (ppm)
A, B, C signal integration areas
1
Figure 1 — Example of a Text H-NMR spectrum for an S-SBR
3.6.2 Normal
...
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