ISO 14322:2012
(Main)Plastics — Epoxy resins — Determination of degree of crosslinking of crosslinked epoxy resins by differential scanning calorimetry
Plastics — Epoxy resins — Determination of degree of crosslinking of crosslinked epoxy resins by differential scanning calorimetry
Plastiques — Résines époxydes — Détermination du degré de réticulation des résines époxydes réticulées par analyse calorimétrique différentielle
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INTERNATIONAL ISO
STANDARD 14322
First edition
2012-06-15
Plastics — Epoxy resins —
Determination of degree of crosslinking
of crosslinked epoxy resins by
differential scanning calorimetry
Plastiques — Résines époxydes — Détermination du degré de
réticulation des résines époxydes réticulées par analyse calorimétrique
différentielle
Reference number
ISO 14322:2012(E)
©
ISO 2012
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ISO 14322:2012(E)
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ISO 14322:2012(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 14322 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting
materials.
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ISO 14322:2012(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 an approach is inadequate in cases in which the test sample is to be evaluated as is or is to be
examined under various crosslinking conditions. This International Standard 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 comparing the heat of the crosslinking
reaction for the test sample with that of a reference sample, using a differential scanning calorimeter.
The advantages of this method are that sample preparation is simple and measurements can be made with
very small amounts of sample. For these reasons, this International Standard is useful for investigations of,
and in establishing conditions for, crosslinking reactions. It can also be used for production and quality control.
Finally, since epoxy resin systems are highly diverse, the applicability of this International Standard to each
resin system needs be established. A technique to test the applicability to an epoxy resin system is included
in the standard.
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INTERNATIONAL STANDARD ISO 14322:2012(E)
Plastics — Epoxy resins — Determination of degree of
crosslinking of crosslinked epoxy resins by differential
scanning calorimetry
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 ensure compliance with any regulatory requirements.
1 Scope
This International Standard specifies a method whereby the heat of reaction generated during epoxy resin
crosslinking is measured by differential scanning calorimetry (DSC). The degree of crosslinking is determined
based on this result.
This method is applicable to epoxy resin systems with a moderate or slow crosslinking-reaction speed. It might
not be applicable to systems with a fast crosslinking-reaction speed at ambient temperature.
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 11357-1:2009, Plastics — Differencial scanning calorimetry (DSC) — Part 1: General principles
ISO 11409:1993, Plastics — Phenolic resins — Determination of heats and temperatures of reaction by
differential scanning calorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11357-1 and the following apply.
3.1
degree of crosslinking
value, calculated in accordance with Equation (2) in Clause 8, which indicates the extent of the crosslinking
reaction of an epoxy resin system, expressed as a percentage
3.2
uncrosslinked epoxy resin system
epoxy resin system immediately after mixing the system components, before any crosslinking has taken place
3.3
total heat of reaction
gross amount of reaction heat produced by an uncrosslinked epoxy resin system (see 3.2) during complete
crosslinking, as determined by DSC, expressed in joules/gram
4 Principle
The total heat of reaction is first measured by DSC, using a test sample taken from the uncrosslinked epoxy
resin system. Curve A in Figure 1 is an example of such a DSC curve.
The heat of reaction of a test sample of the (partly) crosslinked resin system under investigation is then
measured, using the same DSC apparatus and under the same conditions as those used to measure the
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ISO 14322:2012(E)
total heat of reaction, in order to determine the heat of reaction due to the remaining reactive groups as the
reaction goes to completion. Curves B1 and B2 in Figure 1 are examples of DSC curves obtained with such
test samples.
Curve B1 shows a case where crosslinking did not progress to a large extent before the DSC measurement
and curve B2 shows a case where crosslinking progressed considerably before the DSC measurement.
The degree of crosslinking of the (partly) crosslinked resin system is determined from the heat of reaction of
this crosslinked resin system and the total heat of reaction of the uncrosslinked resin system [see Equation (2)
in Clause 8].
Key
X temperature or time
Y heat flow rate (exothermic)
Figure 1 — DSC curve (schematic)
Crosslinking epoxy resin systems are highly diverse, and the systems to which this International Standard
...
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