EN ISO 62:1999

SLOVENSKI STANDARD
SIST EN ISO 62:2000
01-maj-2000
3ROLPHUQLPDWHULDOL'RORþDQMHDEVRUSFLMHYRGH,62
Plastics - Determination of water absorption (ISO 62:1999)
Kunststoffe - Bestimmung der Wasseraufnahme (ISO 62:1999)
Plastiques - Détermination de l'absorption d'eau (ISO 62:1999)
Ta slovenski standard je istoveten z: EN ISO 62:1999
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 62:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 62:2000

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SIST EN ISO 62:2000

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SIST EN ISO 62:2000

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SIST EN ISO 62:2000

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SIST EN ISO 62:2000
INTERNATIONAL ISO
STANDARD 62
Second edition
1999-02-01
Plastics — Determination of water
absorption
Plastiques — Détermination de l'absorption d'eau
A
Reference number
ISO 62:1999(E)

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SIST EN ISO 62:2000
ISO 62:1999(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.
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.
International Standard ISO 62 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 6,
Ageing, chemical and environmental resistance.
This second edition cancels and replaces the first edition (ISO 62:1980), of which it constitutes a technical revision.
Annexes A and B of this International Standard are for information only.
©  ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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ISO 62:1999(E)
Introduction
Plastics exposed to water are subject to several different effects:
a) dimensional changes (e.g. swelling) caused by absorption of water;
b) extraction of water-soluble components; and
c) changes in other properties.
However, exposure to humidity, immersion, and exposure to boiling water can result in distinctly different material
responses. The equilibrium moisture content can be used to compare the amount of water absorbed by different
types of plastics when they are exposed to moisture. Moisture content determined under non-equilibrium conditions
can be used to compare different batches of the same material and to determine the diffusion constant of the
material when determined under carefully controlled non-equilibrium exposure conditions to moisture and when
using plastic specimens of defined dimensions.
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SIST EN ISO 62:2000
INTERNATIONAL STANDARD  © ISO ISO 62:1999(E)
Plastics — Determination of water absorption
1 Scope
1.1  This International Standard describes a procedure for determining the moisture absorption properties in the
“through-the-thickness” direction of flat or curved-form solid plastics. This International Standard also describes
procedures for determining the amount of water absorbed by plastic specimens of defined dimensions, when
immersed in water or when subjected to humid air under controlled conditions. The “through-the-thickness” moisture
diffusion coefficient can be determined for single-phase material by assuming Fickian diffusion behaviour with
constant moisture absorption properties through the thickness of the test specimen. This model is valid for
homogeneous materials and for reinforced polymer-matrix composites tested below their glass transition
temperature. However, some two-phase matrices such as hardened epoxies may require a multi-phase absorption
model which is not covered by this International Standard.
1.2  Ideally the best comparison of the water absorption properties and/or diffusion coefficients of materials should
be carried out only using the equilibrium moisture content of plastics exposed to identical conditions. The
comparison of materials using properties at moisture equilibrium does not assume, and is therefore not limited to,
single-phase Fickian diffusion behaviour.
1.3  Alternatively, water absorption of plastic specimens of defined dimensions exposed to immersion or humidity
under controlled conditions but for an arbitrary time period can be used to compare different batches of the same
material or for quality control tests of a given material. For this type of comparison, it is essential that all test
specimens be of identical dimensions and, as nearly as possible, have the same physical attributes, e.g. surface
smoothness, internal stresses, etc. However, moisture equilibrium is not reached under these conditions. Therefore,
results from this type of test cannot be used to compare the water absorption properties of different types of
plastics. For the more reliable results, simultaneous tests are recommended.
1.4  The results obtained using the methods described in this International Standard are applicable to most plastics
but are not applicable to cellular plastics, granulates, or powders which can show additional absorption and capillary
effects. Plastics exposed to moisture under controlled conditions for defined periods of time provide relative
comparisons between them. The tests described for determination of diffusion coefficient may not be applicable to
all plastics. Plastics that cannot retain their shape when immersed in boiling water should not be compared using
method 2 in 6.3.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
1)
ISO 175:— , Plastics — Determination of the effects of liquid chemicals, including water.
ISO 294-3:1996, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small plates.
ISO 2818:1994, Plastics — Preparation of test specimens by machining.

1) To be published. (Revision of ISO 175:1981)
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3 Principle
Test specimens are immersed in distilled water at 23 °C or in boiling distilled water, or exposed to 50 % relative
humidity, at given temperatures for prescribed times. The amount of water absorbed by the test specimen is
determined by measuring its change in mass, i.e. the difference of its initial mass from that after exposure to water,
and is expressed as a percentage of the initial mass. If required, the amount of water lost after drying the test
specimens can also be determined.
In some applications, 70 % to 90 % relative humidity and temperatures of 70 °C to 90 °C may be necessary. Higher
relative humidity and temperature conditions than those recommended in this International Standard may be used
by agreement between interested parties. When relative humidity and temperature conditions other than those
recommended are used, a complete description of these conditions (with appropriate tolerances) shall be included
in the test report.
4 Apparatus
4.1  Balance, with an accuracy of – 0,1 mg (see clause 6, note 3).
4.2  Oven, with forced-air convection or vacuum, maintained at (50,0 – 2,0) °C or at any other agreed temperature
(see clause 6, note 2).
4.3  Containers, of distilled water, or water of equivalent purity, equipped with a means of heating and maintaining
the temperature specified.
4.4  Desiccator, with a desiccant (e.g. P O ).
2 5
4.5  Means of measuring dimensions of test specimens, to an accuracy of – 0,1 mm, if required.
5 Test specimens
5.1 General
For each material evaluated, test at least three test specimens. Test specimens of the required dimensions may be
prepared by moulding or extrusion. The methods used for preparation of all test specimens shall be included in the
test report.
NOTE   The results of this method may be influenced by surface effects. For some materials, different results can be obtained
between moulded specimens and specimens cut from a larger sheet.
Any contaminant on the test specimen surface which could influence water absorption shall be removed by a
cleaning agent which does not attack the plastic, the degree of attack being determined in accordance with
ISO 175:—, [see for example in 5.6, table 1, notation “none” (no change in appearance)]. Allow specimens to dry at
23 °C and 50 % relative humidity for at least 2 h after cleaning and before beginning the test. Wear clean gloves
when handling test specimens to prevent contamination.
The cleaning agent shall have no effect on water absorption. When determining moisture equilibrium content
according to 6.2 (method 1) and 6.5 (method 4) the effects of the cleaning agent can be ignored.
5.2 Square-shaped test specimens for homogeneous plastics
Unless otherwise specified or agreed by all interested parties, dimensions and tolerances of the square-shaped
specimens should be the same as those given in ISO 294-3:1996, type D1. They can be prepared by moulding
according to ISO 294-3:1996, using conditions given in standards applicable to the material being tested (or using
conditions recommended by the material supplier). For some materials, such as polyamides, polycarbonates, and
some reinforced plastics, use of a 1 mm thick specimen may not give meaningful results. Furthermore, some
product specifications require use of thicker test specimens for the characterization of water absorption. In these
cases, test specimens of (2,05 – 0,05) mm thickness may be used. If specimens other than those 1 mm thick are
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used, the specimen thickness used shall be indicated in the test report. There are no requirements for the radius of
the edges and corners. However, they shall be smooth and clean to prevent material from the edges and corners
from being lost during the test.
Some materials may exhibit mould shrinkage. If specimens of these materials are prepared using a mould with
dimensions at the lower limits specified in ISO 294-3:1996, the final dimensions of the test specimens may be
beyond the tolerances given in this International Standard and shall be noted in the test report.
5.3 Test specimens of reinforced plastics affected by anisotropic diffusion effects
For some reinforced plastic materials, such as carbon fibre reinforced epoxies, anisotropic diffusion effects caused
by reinforcing material may produce erroneous results when small specimens are used. Where this is of concern,
test specimens that meet one of the following requirements shall be used and the specific dimensions and methods
of test specimen preparation shall be included in the test report.
a) A nominally square-shaped plate or curved panel with dimensions that satisfies the relation:
w ¶ 100 d
where
w is the nominal length of one side, in millimetres, and,
d is the nominal thickness, in millimetres.
b) A 100 mm · 100 mm square-shaped plate with stainless steel or aluminium foil bonded to the edges so that
moisture absorption through the edges is minimized. When this specimen is prepared, care shall be taken to
weigh the specimen before and after bonding of the foil in order to obtain the mass increase due to the foil and
the adhesive. Use only poorly absorbing adhesive which will not affect the results.
5.4 Tubular test specimens
Unless specifically required by other International Standards, tubular test specimens shall have the following
dimensions.
a) For tubes having an internal diameter of 76 mm or less, cut sections of tube that are (25 – 1) mm in length from
a longer tube of the material being evaluated. The cut shall be made perpendicular to the longitudinal axis of
the tube. The cut can be made by machining, sawing, or shearing and shall produce smooth edges free from
cracks.
b) For tubes having an internal diameter larger than 76 mm, cut rectangular specimens (76 – 1) mm in length
(measured along the outside surface of the tube) by (25 – 1) mm in width. The cut edges shall be smooth and
free from cracks.
5.5 Rod-shaped test specimens
Rod-shaped test specimens shall have the following dimensions.
a) For rods 26 mm in diameter or less, cut a section of (25 – 1) mm in length. The cut shall be made perpendicular
to the longitudinal axis of the rod. The diameter of the test specimen shall be the diameter of the rod.
b) For rods larger than 26 mm in diameter, cut a section of (13 – 1) mm in length. The cut shall be made
perpendicular to the longitudinal axis of the rod. The diameter of the test specimen shall be the diameter of the
rod.
5.6 Specimens cut from finished products, extrusion compounds, sheets or laminates
Unless required by another International Standard, cut a piece from the product that:
 meets the requirements for the square-shaped test specimen, or
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 has a length and width of (61 – 1) mm and has the same shape (thickness and curves) of the material being
tested.
The machining conditions used to prepare the test specimens shall be agreed by all interested parties.
...