ISO 20368:2017

INTERNATIONAL ISO
STANDARD 20368
First edition
2017-11
Plastics — Epoxy resins —
Determination of degree of
crosslinking of crosslinked epoxy
resins by Fourier Transform Infrared
(FTIR) Spectroscopy
Plastiques — Résines époxy — Détermination du degré de
réticulation des résines époxy réticulées par spectroscopie infrarouge
à transformée de Fourier (FTIR)
Reference number
ISO 20368:2017(E)
©
ISO 2017

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ISO 20368:2017(E)

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© ISO 2017, Published in Switzerland
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ISO 20368:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Materials . 3
6 Apparatus . 3
7 Procedure. 4
7.1 Preparation of measuring . 4
7.2 Preliminary test . 4
7.2.1 General. 4
7.2.2 Procedure for preliminary test . 4
7.3 FTIR measurement on the crosslinked sample under investigation . 5
8 Expression of results . 5
9 Precision . 5
9.1 General . 5
9.2 Materials and crosslinking conditions . 5
9.3 Precision of the method . 6
10 Test report . 6
Bibliography . 7
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ISO 20368:2017(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
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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).
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URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12,
Thermosetting materials.
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ISO 20368:2017(E)

Introduction
It is possible to determine the degree of crosslinking of a crosslinked epoxy resin by observing changes
in its mechanical, electrical or thermal properties.
However, such approaches are inadequate in cases where the test sample is to be examined under
various crosslinking conditions. This document provides a method whereby the degree of crosslinking
is determined without the need for complicated procedures for preparing, conditioning or configuring
the test sample. The degree of crosslinking is determined by measuring the disappearance of the epoxy
group during the resin crosslinking, using Fourier Transform Infrared spectroscopy.
The advantages of this method are that sample preparation is simple, measurements can be made with
very small amounts of resin and it is possible to measure the reaction rate of the epoxy group for an
epoxy compound containing another active functional group. For these reasons, this document is useful
for investigations and for establishing conditions for crosslinking reactions. It can also be used for
production and quality control.
Since epoxy resin systems are highly diverse, the applicability of this document to each resin system is
intended to be established prior determination. A technique to test the applicability to any epoxy resin
system is included in this document.
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INTERNATIONAL STANDARD ISO 20368:2017(E)
Plastics — Epoxy resins — Determination of degree
of crosslinking of crosslinked epoxy resins by Fourier
Transform Infrared (FTIR) Spectroscopy
SAFETY STATEMENT — Persons using this document should be familiar with normal laboratory
practice, if applicable. This document does not purport to address all of the safety concerns, 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.
1 Scope
This document specifies a method for determining the degree of crosslinking of crosslinked epoxy
resins by the disappearance of the epoxy group during epoxy resin crosslinking measured by Fourier
Transform Infrared (FTIR) (with a transmittance mode) spectroscopy.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the
...