ISO 22821:2021

Carbon-fibre-reinforced composites — Determination of fibre weight content by thermogravimetry (TG)

This document specifies a thermogravimetric method for the determination of fibre weight content by weight percent, of carbon fibre reinforced composites. This method applies to pre-products, such as, prepregs, parts and products of carbon fibre reinforced composites.

Composites renforcés de fibres de carbone — Détermination de la teneur en masse de fibres par thermogravimétrie (TG)

General Information

• Status: Published
• Publication Date: 07-Jan-2021
• ICS: 83.120 - Reinforced plastics
• Technical Committee: ISO/TC 61/SC 13 - Composites and reinforcement fibres
• Drafting Committee: ISO/TC 61/SC 13/WG 2 - Laminates and moulding compounds
• Current Stage: 6060 - International Standard published
• Start Date: 08-Jan-2021
• Due Date: 09-Sep-2020
• Completion Date: 08-Jan-2021

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22821
First edition
2021-01
Carbon-fibre-reinforced composites —
Determination of fibre weight content
by thermogravimetry (TG)
Composites renforcés de fibres de carbone — Détermination de la
teneur en masse de fibres par thermogravimétrie (TG)
Reference number
ISO 22821:2021(E)
©
ISO 2021

---------------------- Page: 1 ----------------------
ISO 22821:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 22821:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope .1
2 Normative references .1
3 Terms and definition .1
4 Principle .1
5 Reagents .1
6 Apparatus — Thermogravimetric analyser .2
7 Preparation of samples.2
7.1 Conditioning of samples . 2
7.2 Test specimen . 2
8 Test procedure .3
8.1 Description of the operating steps . 3
8.2 Test processes . 3
9 Expression of results .4
9.1 Data recordings and analyses . 4
9.2 Determination of fibre content . 4
10 Precision .4
11 Test report .4
Annex A (informative) Example of thermogram .6
Annex B (informative) Precision — Reproducibility .9
Bibliography .10
© ISO 2021 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 22821:2021(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 of 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 www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13,
Composites and reinforcement fibres.
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 © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 22821:2021(E)

Introduction
Methods for the determination of fibre content of carbon fibre reinforced plastics has been established
in ISO 14127. The fibre mass in the composite sample is derived by removing the plastic/polymer part
in the sample by combustion using burner and the use of strong acid in ISO 14127. These methods are
not recommended on the grounds of safety and reagent waste. The determination method of the content
of carbon black in the rubber and rubber products is regulated by ISO 9924-3. A thermogravimeter
is employed as the apparatus to remove the rubber part of the sample in ISO 9924-3. Currently,
thermogravimeters are produced commercially with accuracy, repeatability and reproducibility
sufficient for the determination of fibre content in carbon fibre reinforced plastics. In this document, a
thermogravimeter is used as the apparatus to remove the plastic/polymer part of the composite sample.
© ISO 2021 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 22821:2021(E)
Carbon-fibre-reinforced composites — Determination of
fibre weight content by thermogravimetry (TG)
1 Scope
This document specifies a thermogravimetric method for the determination of fibre weight content by
weight percent, of carbon fibre reinforced composites.
This method applies to pre-products, such as, prepregs, parts and products of carbon fibre reinforced
composites.
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 291, Plastics — Standard atmospheres for conditioning and testing
3 Terms and definition
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
fibre weight content
w
f
ratio of fibre weight to total weight of composite, same as fibre content by
weight; expressed as a percentage
4 Principle
A weighed test specimen is heated following a pre-set programme in a known atmosphere.
Initial pyrolysis in an inert atmosphere (nitrogen) is followed by combustion in an oxidizing atmosphere.
Generally, the reactions that generate mass variations are decompositions, oxidations, or reactions
volatilizing a constituent.
Plotting the loss of mass as a function of temperature gives a quantitatively usable thermogram, which
is characteristic of the material.
5 Reagents
5.1 Nitrogen gas, of minimal purity 99,995 % mass fraction, with an oxygen content of less than
10 mg/kg (ppm) and hydrocarbon content less than 1,5 mg/kg (ppm).
© ISO 2021 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 22821:2021(E)

5.2 Dry air, with no detectable trace of oil.
The air used may be reconstituted nitrogen and oxygen of purity minimum 99,5 % mass fraction. In
some cases, pure oxygen may be used.
6 Apparatus — Thermogravimetric analyser
6.1 General
Various types of analyser are commercially available. The basic components of an analyser are listed in
6.2 to 6.8.
6.2 Thermogravimetric balance, comprising a microbalance provided with a pan made from a non-
oxidizable material, that can weigh up to 50 mg, is readable to the nearest 1 µg, and equipped with an
oven capable of being maintained
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22821
ISO/TC 61/SC 13
Carbon-fibre-reinforced composites —
Secretariat: JISC
Determination of fibre wight content
Voting begins on:
2020­10­09 by thermograrvimetry (TG)
Voting terminates on:
2020­12­04
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 22821:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

---------------------- Page: 1 ----------------------
ISO/FDIS 22821:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 22821:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope .1
2 Normative references .1
3 Terms and definition .1
4 Principle .1
5 Reagents .1
6 Apparatus — Thermogravimetric analyser .2
7 Preparation of samples.2
7.1 Conditioning of samples . 2
7.2 Test specimen . 2
8 Test procedure .3
8.1 Description of the operating steps . 3
8.2 Test processes . 3
9 Expression of results .4
9.1 Data recordings and analyses . 4
9.2 Determination of fibre content . 4
10 Precision .4
11 Test report .4
Annex A (informative) Example of thermogram .6
Annex B (informative) Precision — Reproducibility .9
Bibliography .10
© ISO 2020 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/FDIS 22821:2020(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 non­governmental, 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 of 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 www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13,
Composites and reinforcement fibres.
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 © ISO 2020 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 22821:2020(E)

Introduction
Methods for the determination of fibre content of carbon fibre reinforced plastics has been established
in ISO 14127. The fibre mass in the composite sample is derived by removing the plastic/polymer part
in the sample by combustion using burner and the use of strong acid in ISO 14127. These methods are
not recommended on the grounds of safety and reagent waste. The determination method of the content
of carbon black in the rubber and rubber products is regulated by ISO 9924­3. A thermogravimeter
is employed as the apparatus to remove the rubber part of the sample in ISO 9924­3. Currently,
thermogravimeters are produced commercially with accuracy, repeatability and reproducibility
sufficient for the determination of fibre content in carbon fibre reinforced plastics. In this document, a
thermogravimeter is used as the apparatus to remove the plastic/polymer part of the composite sample.
© ISO 2020 – All rights reserved v

---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22821:2020(E)
Carbon-fibre-reinforced composites — Determination of
fibre wight content by thermograrvimetry (TG)
1 Scope
This document specifies a thermogravimetric method for the determination of fibre weight content by
weight percent, of carbon fibre reinforced composites.
This method applies to pre-products, such as, prepregs, parts and products of carbon fibre reinforced
composites.
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 291, Plastics — Standard atmospheres for conditioning and testing
3 Terms and definition
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
fibre weight content
w
f
ratio of fibre weight to total weight of composite, same as fibre content by
weight; expressed as a percentage
4 Principle
A weighed test specimen is heated following a pre­set programme in a known atmosphere.
Initial pyrolysis in an inert atmosphere (nitrogen) is followed by combustion in an oxidizing atmosphere.
Generally, the reactions that generate mass variations are decompositions, oxidations, or reactions
volatilizing a constituent.
Plotting the loss of mass as a function of temperature gives a quantitatively usable thermogram, which
is characteristic of the material.
5 Reagents
5.1 Nitrogen gas, of minimal purity 99,995 % mass fraction, with an oxygen content of less than
10 mg/kg (ppm) and hydrocarbon content less than 1,5 mg/kg (ppm).
© ISO 2020 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO/FDIS 22821:2020(E)

5.2 Dry air, with no detectable trace of oil.
The air used may be reconstituted nitrogen and oxygen of purity minimum 99,5 % mass fraction. In
some cases, pure oxygen may be used.
6 Apparatus — Thermogravimetric analyser
6.1 General
Various types of analyser are commercially available. The basic components of an analyser are listed in
6.2 to 6.8.
6.2
...