ISO 22836:2020

INTERNATIONAL ISO
STANDARD 22836
First edition
2020-09
Fibre-reinforced composites —
Method for accelerated moisture
absorption and supersaturated
conditioning by moisture using sealed
pressure vessel
Composites renforcés de fibres — Méthode pour l'absorption
accélérée de l'humidité et le conditionnement sursaturé en humidité à
l'aide d'un récipient sous pression scellé
Reference number
ISO 22836:2020(E)
©
ISO 2020

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ISO 22836:2020(E)

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ISO 22836:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Test procedure . 4
6.1 Weighing test specimens . 4
6.2 Obtaining supersaturated moisture absorption . 4
6.3 Sampling of test materials with supersaturated moisture content . 4
6.4 Confirming the saturated moisture absorbing . 4
6.5 Measuring mechanical or thermal properties . 5
7 Precision . 5
8 Test reports . 6
Annex A (informative) Examples of CFRP and CFRTP specimens with supersaturated
moisture condition . 7
Bibliography .11
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ISO 22836:2020(E)

Foreword
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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.
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ISO 22836:2020(E)

Introduction
Mechanical properties of fibre reinforced thermoset or thermoplastics with saturated moisture
content under used conditions need to be determined for the specification of these materials. However,
the moisture content of the fibre reinforced thermoset or thermoplastic materials immediately after
production are usually lower than that during use, because the production process is under a higher
temperature and uses dried ingredients for optimum quality control. The fibre reinforced materials
absorb moisture under the used conditions and reach a saturated moisture content after a long period,
for example after 6 months. Accordingly, the accelerated moisture absorption method (70 °C, 75 %
RH) is specified in ASTM D5229/D5229M for determining the properties at saturation. However, the
absorption time is still long (over three months) using this method.
This document specifies a method for obtaining practical saturated moisture absorption for effective
and shorter research and development process of thermoset and thermoplastic materials. The method
uses a sealed pressure vessel at a higher temperature with saturated water vapour condition (120 °C,
0,2 MPa of water vapour pressure).
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INTERNATIONAL STANDARD ISO 22836:2020(E)
Fibre-reinforced composites — Method for accelerated
moisture absorption and supersaturated conditioning by
moisture using sealed pressure vessel
1 Scope
This document specifies accelerated moisture absorption properties and supersaturated conditioning
by moisture for fibre-reinforced plastics) using sealed pressure vessel at higher temperature than
100 °C with saturated water vapour at used heating temperature.
The purpose of this moisture absorbing procedure is to screen test specimens with moisture by
mechanical or thermal properties.
This document applies to carbon-fibre materials and their products with either thermoset or
thermoplastic matrices, with a T greater than 150 °C. This document can also apply to materials
g
reinforced with other fibres (e.g. glass-fibres) with a T greater than 150 °C.
g
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 472, Plastics — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following 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
additional moisture content
mass percentage of additionally absorbing moisture in the test material to total mass of the material
and moisture already existing in this material
Note 1 to entry: See Formula (1).
3.2
initial moisture content
mass percentage of absorbed moisture in the test material at the initial time
Note 1 to entry: See Formula (3).
3.3
supersaturated conditioning by moisture
moisture absorbing conditions in the test material at room temperature cooled from the saturated
moisture absorbing condition at higher temperature and higher humidity, such as saturated water
vapour pressure at used higher temperature
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ISO 22836:2020(E)

3.4
accelerated moisture absorption
moisture absorption by process with specific conditions such as higher temperature (e.g. 120 °C) and
higher pressure of moisture (0,2 MPa) to obtain saturated moisture content (3.5) during shorter time
3.5
saturated moisture content
moisture content from absorption condition with supersaturated moisture at lower temperature (e.g.
room temperature) from higher temperature (e.g. 120 °C) where specimen has saturated moisture content
4 Principle
To obtain almost similar saturated moisture condition in a test material at room temperature for
shorter time, the test material absorbs moisture at higher temperature and higher humidity conditions
such as 120 °C and 0,2 MPa of saturated water vapour pressure without air (oxygen) gas.
Higher temperature causes higher diffusion rate of water molecules in materials and higher water
vapour pressure causes higher frequencies of water molecules uptake at the surface of the material
from outside. Therefore, equilibrium and saturated moisture condition to the materials is obtained
during shorter time. However, if this material with saturated moisture is cooled to room temperature,
this material absorbs supersaturated moisture because of slow diffusion rate inside of water molecules
and slow releasing rate of water molecules at the surface.
In this way, supersaturated moisture condition for thermoset and thermoplastic matrices is obtained. It
is important that this procedure does not cause degradation of the test material. Mechanical properties
should be monitored to be stable during repeating these absorbing and desorbing (drying) processes.
In addition, this condition is simulated condition for real condition to obtain saturated equilibrium
moisture content at room tem
...