ISO 19984-2:2017

Rubber and rubber products — Determination of biobased content — Part 2: Biobased carbon content

ISO 19984-2:2017 specifies measuring methods for the determination of biobased carbon contents in rubber and rubber products, including polyurethanes. The methods focus on carbon atoms in rubber or rubber products, and determine whether the carbon-containing component is biobased or not judging from the concentration of 14C, radiocarbon isotope. ISO 19984-2:2017 applies to rubber and rubber products such as raw materials, materials and final products.

Élastomères et produits à base d'élastomères — Détermination de la teneur en composés biosourcés — Partie 2: Teneur en carbone biosourcé

General Information

• Status: Published
• Publication Date: 13-Aug-2017
• ICS: 83.060 - Rubber
• Technical Committee: ISO/TC 45/SC 2 - Testing and analysis
• Drafting Committee: ISO/TC 45/SC 2 - Testing and analysis
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 07-Nov-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19984-2
First edition
2017-08
Rubber and rubber products —
Determination of biobased content —
Part 2:
Biobased carbon content
Élastomères et produits à base d’élastomères — Détermination de la
teneur en composés biosourcés —
Partie 2: Teneur en carbone biosourcé
Reference number
ISO 19984-2:2017(E)
©
ISO 2017

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ISO 19984-2:2017(E)

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ISO 19984-2:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Sampling . 3
14
6 Measuring method of biobased carbon content by determination of C content for
rubber products and raw materials . 3
6.1 General . 3
14
6.2 Sample preparation and two methods to determine C concentration . 4
6.3 Calculation of the biobased carbon content . 4
6.3.1 General. 4
6.3.2 Correction factor . 4
TC
6.3.3 Calculation of χ , the biobased carbon content by Method A (AMS) . 5
B
TC
6.3.4 Calculation of χ , the biobased carbon content by Method B (LSC) . 5
B
6.3.5 Examples . 5
7 Precision . 6
8 Test report . 6
Annex A (normative) Method A — Determination by accelerator mass spectrometry (AMS) .7
Annex B (normative) Method B — Determination by liquid scintillation counter (LSC).10
Annex C (informative) Examples of the determination of biobased carbon content for
rubber and rubber products .13
Annex D (informative) Determination of the biobased carbon content of a tyre .15
Annex E (informative) Precision results from an interlaboratory test programme .18
Bibliography .20
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ISO 19984-2:2017(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 voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 2, Testing and analysis.
A list of all parts in the ISO 19984 series can be found on the ISO website.
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ISO 19984-2:2017(E)

Introduction
The use of biomass materials in rubber compounds helps to decrease the rubber industry’s dependence
on fossil resources. It is also expected to lead to a reduction of carbon dioxide emission, reducing global
warming and promoting a sustainable global environment.
In the ISO 19984 series, biomass is the term used for the biological material from living or recently
living organisms such as wood and agricultural waste materials.
Industrial scale biomass is now readily being grown from numerous types of plants sources and a variety
of tree species. Biomass nowadays also includes plant or animal matter used for the production of fibres
or chemicals. It may also include biodegradable wastes. Biomass excludes organic materials which have
been transformed by geological processes into substances, such as petroleum or coal. Although fossil
fuels have their origin in ancient biomass, they are not considered biomass by the generally accepted
definition because they contain carbon that has been “out” of the modern carbon cycle.
The composition of biomass is mainly carbon, hydrogen and oxygen. Nitrogen and small quantities of
other elements can also be found.
The ISO 19984 series specifies methods for the determination of the biobased content of rubber and
rubber products. The results will give manufacturers and users a quantitative indication of their
contribution to the preservation of the environment.
ISO 19984-1 specifies how to categorize constituents of rubber and rubber products and also how to
calculate the biobased content using the compound formulation and the chemical structure of each
constituent.
ISO 19984-2 specifies how to determine the biobased carbon content by radio chemical analyses,
14
i.e. determination of C. It can be obtained from the fraction of carbon atoms derived from biomass
against the whole amount of carbon atoms in the rubber or rubber products. The methods specified in
ISO 19984-2 allow consumers to determine the biobased carbon content even when the formulation of
the rubber is unavailable.
ISO 19984-3 specifies how to separate rubber compounds into constituents, how to obtain each
constituent’s composition ratio and how to determine the biobased carbon content of each constituent
by chemical analyses. Thus, the biobased mass content for each constituent can be derived and the
biobased mass content for the whole rubber can be obtained by summing up all the constituent values.
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INTERNATIONAL STANDARD ISO 19984-2:2017(E)
Rubber and rubber products — Determination of biobased
content —
Part 2:
Biobased carbon content
WARNING 1 — Persons using this document should be familiar with normal laboratory practice.
This document 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
determine the applicability of any other restrictions.
WARNING 2 — Certain procedures specified in this document might 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 document specifies measuring methods for the determination of biobased carbon contents in
rubber and rubber products, including polyurethanes. The methods focus on carbon atoms in rubber or
rubber products, and determine whether the carbon-containing component is biobased or not judging
14
from the concentration of C, radiocarbon isotope.
This document applies to rubber and rubber products such as raw materials, materials and final
products.
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 123, Rubber latex — Sampling
ISO 124, Latex, rubber — Determination of total solids content
ISO 1382, Rubber — Vocabulary
ISO 1795, Rubber, raw natural and raw synthetic — Sampling and further preparative procedures
ISO 4661-2, Rubber, vulcanized — Preparation of samples and test pieces — Part 2: Chemical tests
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 19242, Rubber — Determination of total sulfur content by ion chromatography
ISO 19984-1, Rubber and rubber products — Determination of biobased content — Part 1: General
principles and calculation methods using the formulation of the rubber compound
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1382 and ISO 19984-1 and the
following apply.
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ISO 19984-2:2017(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
percent modern carbon
pMC
14
normalized and standardized value for the amount of the C isotope in a sample, calculated relative to the
14 1)
standardized and normalized C isotope amount of oxalic acid standard reference material, SRM 4990c
Note 1 to entry: The reference value of 100 % biobased carbon is given in Table 2.
3.2
14
C activity
14
relative concentration of radiocarbon C expressed as a counting of β-irradiation from the decayed
radiocarbon atoms per minute
14
Note 1 to entry: The unit of C activity is “dpm” (decay per minute).
14
Note 2 to entry: The C activity is determined relatively using standard reference material (SRM 4990c) whose
14
C activity is set at 13,56 dpm.
4 Principle
This document specifies those methods to determine the biobased carbon contents derived from
biomass resources.
When the formulation of the rubber product is available, the biobased carbon content can be calculated
(see ISO 19984-1). The biobased carbon content is defined as the amount of biobased carbon to the total
carbon in rubber or rubber products as Formula (1):
C
TC B
χ = ×100 (1)
B
CC++ C
BF NB
where

TC
is the biobased carbon content (%);
χ
B
C C and C are the mass of biobased, fossil-based and non-biobased carbon, respectively.
B, F NB
When there is no available information for the rubber or the rubber product, the biobased carbon
14 14
content can be determined by the C concentration. Due to its radioactive decay, C hardly exists
14
in fossil products older than 20 000 years to 30 000 years. Therefore, the C present in products is
estimated to have come from recent atmospheric carbon dioxide, and consequently, it can be considered
as a tracer of recently produced bio-products.
The biobased carbon content values determined in accordance with this document can also be compared
to the theoretical values calculated from the formulation, so that the reliability of the information about
the rubber in the rubber product is confirmed.
In order to determine the biobased mass content for raw rubber, organic ingredient, rubber products or
separated constituents, refer to ISO 19984-3.
1) SRM 4990c is an example of a suitable product supplied by the US National Institute of Standards and Technology.
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
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ISO 19984-2:2017(E)

5 Sampling
5.1 In the case of latex, carry out sampling in accordance with ISO 123 and dry the sample in
accordance with ISO 124.
5.2 In the case of raw material, carry out sampling in accordance with ISO 15528.
5.3 In the case of raw rubber, carry out sampling in accordance with ISO 1795.
5.4 In the case of vulcanized rubber, carry out sampling in accordance with ISO 4661-2.
NOTE The procedure of washing the surface of samples by acid and alkaline solution, which is a familiar
preparation process for carbon dating, is not necessary.
14
6 Measuring method of biobased carbon content by determination of C
content for rubber products and raw materials
6.1 General
14
Sample preparation and two methods for the determination of the C content are described in this
document. With these modular approaches, it is possible for normally equipped laboratories to prepare
14
samples and choose either to determine the C content with their own equipment or to outsource the
determination process to other laboratories who are specialized in this technique.
14
For the collection of the C from the sample, commonly accepted methods for the conversion of the carbon
present in the sample to carbon dioxide are adopted as indicated in Figure 1 (see also A.4.1 and B.4.1).
14
For the measurement of the C content, two methods are adopted that have been generally accepted as
age determination methods as indicated in Figure 1 (see also Annex A and Annex B).
Figure 1 — Outline for the determination of biobased carbon content
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ISO 19984-2:2017(E)

14
6.2 Sample preparation and two methods to determine C concentration
Carry out an oxidation of the sample as specified in A.4.1 and B.4.1. A complete oxidization of all the
carbons present in the sample shall be performed to obtain exact results. The measurement shall be
made according to one of the following two methods:
— Method A [Accelerator mass spectrometry (AMS)]: direct determination of the isotope abundance
14
of C, specified in Annex A;
— Method B [Liquid scintillation counter (LSC)]: indirect determination of the isotope abundance of
14
C through its emission of beta-particles (interaction with scintillation molecules), specified in
Annex B.
The comparison between these test methods is given in Table 1.
14
Table 1 — Characteristics of the measurement methods of C
Relative standard
Method Determination Sample amount Measurement time
deviation
Method A relative ratios between
1 mg to 10 mg 10 min to 30 min 0,2 % to 2,0 %
12 13 14
(AMS) isotope C, C and C
Method B
14
β counts of C decay 0,5 mg to 2,0 g 4 h to 24 h 0,2 % to 10 %
(LSC)
6.3 Calculation of the biobased carbon content
6.3.1 General
TC
14
The biobased carbon content as a fraction to the total carbon content, χ , using the C content value,
B
is determined by calculation from one of the test methods specified in 6.3.3 or 6.3.4, and applying the
correction factor in Table 2.
6.3.2 Correction factor
Before the above-ground hydrogen bomb testing (started around 1955 and terminated in 1962), the
14
atmospheric C level was constant with a few percent range of change for the past millennium. Hence, a
14
sample grown before 1955 has a well-defined “modern” C activity, and the fossil contribution could be
14
determined in a straightforward way. After that, C generated during the bomb-testing era increased
14 14
the atmospheric C level up to 200 % (pMC) and 27,12 dpm ( C activity) in 1962. The values declined
14
gradually, however, to 101 % (pMC) and 13,70 dpm ( C activity), respectively by 2017, because the large
14 12
emission of fossil C during the last decades have contributed to the decrease of the atmospheric C/ C
ratio. The REF value of 100 % biobased carbon is indicated in Table 2 in accordance with ASTM D6866.
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ISO 19984-2:2017(E)

Table 2 — REF value of 100 % biobased carbon in determined year
Year REF (pMC, %)
2015 102,0
2016 101,5
2017 101,0
2018 100,5
2019 100,0
2020 to be determined
14
For the calculation of the biobased carbon content, a C content of 101 pMC [REF used in Formula (2)
and Formula (3)] is considered as a 100 % biobased carbon content for biomass in 2017.
NOTE A hundred (100) % pMC obtained by AMS measurement (Method A) corresponds to 13,56 dpm
obtained by LSC measurement (Method B). A hundred and one (101) % pMC for biomass carbon harvested in
2017 corresponds to 13,70 dpm.
TC
6.3.3 Calculation of χ , the biobased carbon content by Method A (AMS)
B
TC
Calculate the biobased carbon content as a fraction of total carbon, χ , expressed as a percentage,
B
using Formula (2) (see Annex A):
pMC
TC S
χ =×100 (2)
B
REF
where
pMC is the measured value, expressed in pMC, of the sample;
S
REF is the reference value, expressed in pMC (see 6.3.2).
TC
6.3.4 Calculation of χ , the biobased carbon content by Method B (LSC)
B
TC
Calculate the biobased carbon content as a fraction of total carbon, χ , expressed as a percentage,
B
using Formula (3) (see Annex B):
14
C
activity
TC
χ = ×100 (3)
B
REF
13,56××m
100
where
14 14
C is the C activity, expressed in dpm, of the sample obtained by calculation when using
activity
Method B (see Annex B);
REF is the reference value, expressed in pMC, of the sample (see 6.3.2);
m is the mass, expressed in grams, of the sample.
6.3.5 Examples
For examples of biobased carbon content determination, see Annexes C and D.
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ISO 19984-2:2017(E)

7 Precision
See Annex E.
8 Test report
The test report shall include at least the following information:
a) a reference to this document, i.e. ISO 19984-2;
b) all information necessary for complete identification of the rubber material or product tested,
including the origin of the biomass from which the material or product is constituted;
14
c) test method used for the determination of the C content (Method A or B);
13
d) information on whether δ C correction was applied or not (see A.5);
e) method for the oxidation of the carbon (see A.4.1 and B.4.1);
14 14
f) C value expressed in pMC (Method A), or C activity of the sample expressed in dpm (Method B);
g) REF value used;
TC
h) test results: biobased carbon content by total carbon content, χ , expressed as carbon %, of the
B
sample; if the calculating value exceeds 100, the value shall be reported as 100 %;
i) any additional information, including details of any deviations from the test methods and any
operations not specified in this document which could have had influences on the results;
j) date of the test.
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ISO 19984-2:2017(E)

Annex A
(normative)

Method A — Determination by accelerator mass spectrometry
(AMS)
A.1 Principle
14
This annex provides the procedures to determine C amount in rubber or rubber products (including
polyurethane) by accelerator mass spectrometry (AMS).
14
To determine C amount by AMS, the rubber or rubber products shall be converted into carbon
14
graphite. Some AMS apparatus allow to determine C by the form of CO . Follow the manufacturer’s
2
instruction to select the procedure to be applied.
The determination shall always be accompanied by the reference material determinations at the same
time to confirm the accuracy.
A.2 Reagents and materials
2)
A.2.1 Standard reference material, e.g. SRM 4990c .
A.2.2 Copper oxide (CuO).
A.2.3 Sulfur absorbent (e.g. Sulfix or silver ribbon).
A.2.4 Iron or cobalt catalyst.
A.2.5 Hydrogen.
A.2.6 Dry ice.
A.2.7 Organic solvent, acetone or ethanol.
A.2.8 Liquid nitrogen.
A.2.9 Argon and air, for elemental analyser.
A.3 Apparatus
A.3.1 Balance, accurate to the nearest 0,1 mg.
A.3.2 Quartz tube (I.D.; ca. 5 mm, length; ca. 200 mm).
A.3.3 Tube furnace, capable to perform to 1 000 °C adapted to the quartz tube size.
2) SRM 4990c is an example of a suitable product supplied by the US National Institute of Standards and Technology.
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
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ISO 19984-2:2017(E)

A.3.4 Elemental analyser, with sulfur absorbing column.
A.3.5 Gas manifold apparatus.
A.4 Procedure
A.4.1 Oxidation of samples to obtain CO
2
A.4.1.1 Procedures
Obtain CO by either of the methods in A.4.1.2 or A.4.1.3.
2
A.4.1.2 Quartz tube method with copper oxide (CuO)
This method collects CO by mixing homogenized test piece (of 1 mg to 2 mg) with CuO in a sealed,
2
evacuated quartz tube. The sufficient amount of CuO should be added to achieve complete oxidation of
all carbons in the test piece. Practice has shown that over 400 mg of CuO shall be added for each 2 mg
test piece.
NOTE Under insufficient quantity of CuO, carbon black in rubber compounds, which is usually fossil-based
(non-biobased), tends to remain unoxidized, so the relative biobased carbon content is wrongly increased.
Sulfur compounds inhibit conversion of graphite from CO . When the test piece includes sulfur
2
compounds, put a sulfur absorbent such as sulfix or silver ribbon for this procedure.
The tube is heated to 850 °C to 1 000 °C for 3 h to 5 h. The formed CO is collected by breaking the tube
2
using a tube-cracker connected to a gas manifold apparatus.
Purify the collected CO in the gas manifold apparatus using liquid nitrogen and dry ice in ethanol or
2
acetone.
A.4.1.3 Elemental analyser method
This method collects CO using an elemental analyser. Depending on the apparatus, the required
2
amount of the test piece will range from 1 mg to 10 mg.
NOTE Under insufficient oxidation, carbon black in rubber compounds, which is usually fossil-based (non-
biobased), tends to remain unoxidized, so the relative biobased carbon content is wrongly increased.
When the test piece includes sulfur compounds, use a sulfur absorbent column connected to the
elemental analyser to remove sulfur gases such as SO from oxidation gas.
2
The formed CO flows into the gas manifold apparatus connecting to the elemental analyser.
2
Purify the collected CO in the gas manifold apparatus using liquid nitrogen and dry ice in ethanol or
2
acetone.
A.4.2 Conversion to graphite
If the AMS can measure the obtained CO (see A.4.1) directly, this procedure is unnecessary.
2
Transfer the CO to the gas manifold apparatus.
2
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ISO 19984-2:2017(E)

Introduce the gaseous sample in the system as it is released from a quartz tube or after it is trapped in
liquid nitrogen followed by the subsequent heating. Then convert the purified CO to graphite using an
2
iron or cobalt catalyst with hydrogen gas as follows:
CO + 2H → C + 2H O
2 2 2
Repeat the procedure from A.4.1 to A.4.2 with standard reference material.
14
A.4.3 Determination of C concentration
Load the prepared graphite of rubber/rubber products and of standard reference material into the
12 13 14
AMS. The equipment counts the number of each carbon isotope ( C, C and C) and indicates the
14 12 13 12
relative ratios of C/ C as well as C/ C.
A.5 Calculation of the results
14 12
Obtain percent modern carbon (pMC ) values from the C/ C relative ratio (see A.4.3) using
S
Formula (A.1):
A
S
pMC =×pMC (A.1)
S R
A
R
where
pMC is the percent modern carbon value of sample;
S
pMC is the percent modern carbon value of standard reference material;
R
14 12
A is the C/ C relative ratio of radiocarbon of sample;
S
14 12
A is the C/ C relative ratio of radiocarbon of standard reference material.
R
The obtained percent modern carbon (pMC ) values may be corrected using stable isotope ratio
S
13 12
( C/ C) of the test sample and standard reference material. In some areas such as carbon dating, it is
13 12
commonly employed to correct the results with another isotopic ratio ( C/ C). However, the survey in
2013 to 2015 has shown that this correction has little influence on biobased carbon content of rubber
samples. As far as possible, it is preferable to have results without any corrections to avoid confusions.
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ISO 19984-2:2017(E)

Annex B
(normative)

Method B — Determination by liquid scintillation counter (LSC)
B.1 Principle
14
This annex provides the procedures to determine C activity in rubber or rubber products (including
polyurethanes) by liquid scintillation counter (LSC).
14
To determine C activity by LSC, CO obtained from the rubber or rubber products shall be either
2
absorbed to carbamate solution or be converted to benzene.
Each determination shall be accompanied by reference determination to confirm accuracy.
B.2 Reagents and materials
3)
B.2.1 Standard reference materials, e.g. SRM 4990c .
B.2.2 Scintillation liquid.
B.2.3 Absorbent solution.
B.3 Apparatus
B.3.1 Balance, accurate to the nearest 0,1 mg.
B.3.2 Bomb calorimeter, based on ISO 1928.
B.3.3 Tube furnace, as specified in ISO 19242.
B.3.4 Sample oxidizing apparatus.
B.3.5 Liquid scintillation counter (LSC), with a low level counter.
B.3.6 Benzene synthesis apparatus.
B.3.7 Gas bag.
3) SRM 4990c is an example of a suitable product supplied by the US National Institute of Standards and Technology.
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
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ISO 19984-2:2017(E)

B.4 Procedure
B.4.1 Com
...