SIST EN ISO 62:2009
(Main)Plastics - Determination of water absorption (ISO 62:2008)
Plastics - Determination of water absorption (ISO 62:2008)
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. 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. 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 more reliable results, simultaneous tests are recommended. 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 the determination of the diffusion coefficient may not be applicable to all plastics. Plastics that do not retain their shape when immersed in boiling water should not be compared using method 2 (see 6.4).
Kunststoffe - Bestimmung der Wasseraufnahme (ISO 62:2008)
1.1 Diese Internationale Norm beschreibt ein Verfahren zur Bestimmung der Wasseraufnahmeeigen¬schaften von flachen oder gekrümmten festen Kunststoffmaterialien in Richtung der Flächennormalen (Dickenrichtung). Diese Norm beschreibt außerdem Verfahren zur Bestimmung der Wassermenge, die von Kunststoffprobekörpern mit genau festgelegten Maßen unter geregelten Bedingungen aufgenommen wird, wobei die Probekörper eingetaucht oder durch feuchte Luft beansprucht werden. Der Wasserdiffusions¬koeffizient in Richtung der Flächennormalen kann für ein Einphasen Material bestimmt werden, wobei ein Ficksches Diffusionsverhalten mit konstanten Wasseraufnahmeeigenschaften über die Dicke des Probe¬körpers angenommen wird. Dieses Modell gilt für homogene Materialien und verstärkte Verbundstoffe mit polymerer Matrix, die unterhalb ihrer Glasübergangstemperatur geprüft werden. Einige Zweiphasenmatrizes, z. B. gehärtete Epoxidharze, können ein Mehrphasen Absorptionsmodell erfordern, das in der vorliegenden Internationalen Norm nicht behandelt wird.
1.2 Der Vergleich der Wasseraufnahmeeigenschaften und/oder der Diffusionskoeffizienten von Materialien sollte im Idealfall nur mit dem Gleichgewichtswassergehalt von Kunststoffen vorgenommen werden, die iden¬tischen Bedingungen ausgesetzt waren. Der Vergleich von Materialien unter Anwendung von Eigenschaften beim Feuchtigkeitsgleichgewicht setzt kein Ficksches Einphasen Diffusionsverhalten voraus und ist deshalb nicht darauf begrenzt.
1.3 Alternativ kann die Wasseraufnahme von Kunststoffprobekörpern mit genau vorgegebener Geometrie, die für willkürlich festgelegte Zeiträume bestimmten Wasser oder Luftfeuchtebedingungen ausgesetzt werden, zum Vergleich unterschiedlicher Chargen des gleichen Materials oder bei Prüfungen zur Qualitätskontrolle eines bestimmten Materials herangezogen werden.
Plastiques - Détermination de l'absorption d'eau (ISO 62:2008)
L'ISO 62:2008 décrit un mode opératoire permettant de déterminer les propriétés d'absorption de l'humidité dans l'épaisseur de matériaux plastiques solides plats ou courbes. La présente norme décrit également des modes opératoires permettant de déterminer la quantité d'eau absorbée par des éprouvettes de dimensions définies, immergées dans l'eau ou exposées à de l'air humide dans des conditions définies. Le calcul du coefficient de diffusion de l'humidité dans l'épaisseur suppose un matériau fickien monophasé ayant des propriétés constantes d'absorption d'humidité dans l'épaisseur de l'éprouvette. Ce modèle est valable pour les matériaux homogènes et pour les composites renforcés à matrice polymère soumis à essai au-dessous de leur température de transition vitreuse. Toutefois, certaines matrices à deux phases, telles que les époxydes durcis, peuvent nécessiter un modèle d'absorption multiphase qui n'est pas couvert par la présente Norme internationale.
Les résultats obtenus en utilisant les méthodes décrites dans l'ISO 62:2008 s'appliquent à la plupart des plastiques, à l'exception des plastiques alvéolaires, des granulés ou des poudres qui peuvent avoir d'autres effets capillaires et d'absorption. Des expositions pendant un laps de temps fixe permettent des comparaisons relatives des plastiques. Les essais décrits pour la détermination du coefficient de diffusion peuvent ne pas être applicables à tous les plastiques. Les plastiques ne pouvant pas garder leur forme lors de leur exposition à l'eau bouillante ne peuvent pas être comparés en utilisant la méthode 2.
Polimerni materiali - Določanje absorpcije vode (ISO 62:2008)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 62:2009
01-januar-2009
1DGRPHãþD
SIST EN ISO 62:2000
3ROLPHUQLPDWHULDOL'RORþDQMHDEVRUSFLMHYRGH ,62
Plastics - Determination of water absorption (ISO 62:2008)
Kunststoffe - Bestimmung der Wasseraufnahme (ISO 62:2008)
Plastiques - Détermination de l'absorption d'eau (ISO 62:2008)
Ta slovenski standard je istoveten z: EN ISO 62:2008
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 62:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 62:2009
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SIST EN ISO 62:2009
EUROPEAN STANDARD
EN ISO 62
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2008
ICS 83.080.01 Supersedes EN ISO 62:1999
English Version
Plastics - Determination of water absorption (ISO 62:2008)
Plastiques - Détermination de l'absorption d'eau (ISO Kunststoffe - Bestimmung der Wasseraufnahme (ISO
62:2008) 62:2008)
This European Standard was approved by CEN on 28 January 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 62:2008: E
worldwide for CEN national Members.
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SIST EN ISO 62:2009
EN ISO 62:2008 (E)
Contents Page
Foreword.3
2
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SIST EN ISO 62:2009
EN ISO 62:2008 (E)
Foreword
This document (EN ISO 62:2008) has been prepared by Technical Committee ISO/TC 61 "Plastics" in
collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by August 2008, and conflicting national standards shall be withdrawn at
the latest by August 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 62:1999.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 62:2008 has been approved by CEN as a EN ISO 62:2008 without any modification.
3
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SIST EN ISO 62:2009
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SIST EN ISO 62:2009
INTERNATIONAL ISO
STANDARD 62
Third edition
2008-02-15
Plastics — Determination of water
absorption
Plastiques — Détermination de l'absorption d'eau
Reference number
ISO 62:2008(E)
©
ISO 2008
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SIST EN ISO 62:2009
ISO 62:2008(E)
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Published in Switzerland
ii © ISO 2008 – All rights reserved
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SIST EN ISO 62:2009
ISO 62:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Principle. 2
4 Apparatus . 2
5 Test specimens . 2
5.1 General. 2
5.2 Square-shaped test specimens for homogeneous plastics. 3
5.3 Test specimens of reinforced plastics affected by anisotropic diffusion effects. 3
5.4 Tubular test specimens. 3
5.5 Rod-shaped test specimens . 4
5.6 Specimens cut from finished products, extrusion compounds, sheets or laminates . 4
6 Test conditions and procedures . 4
6.1 General. 4
6.2 General conditions . 4
6.3 Method 1: Determination of amount of water absorbed after immersion in water at 23 °C. 5
6.4 Method 2: Determination of amount of water absorbed after immersion in boiling water . 5
6.5 Method 3: Determination of water-soluble matter lost during immersion. 6
6.6 Method 4: Determination of amount of water absorbed after exposure to 50 % relative
humidity . 6
7 Expression of results . 6
7.1 Percentage by mass of water absorbed. 6
7.2 Determination of the water content at saturation and the water diffusion coefficient using
Fick’s laws. 7
8 Precision. 8
9 Test report . 9
Annex A (informative) Correlation between water absorption by test specimens and Fick’s
diffusion laws. 10
Annex B (informative) Precision statement. 12
Bibliography . 15
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SIST EN ISO 62:2009
ISO 62:2008(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 62 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 6, Ageing, chemical
and environmental resistance.
This third edition cancels and replaces the second edition (ISO 62:1999), to which a precision statement has
been added.
iv © ISO 2008 – All rights reserved
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SIST EN ISO 62:2009
ISO 62:2008(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;
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 conditions of
exposure to moisture and when using plastic specimens of defined dimensions.
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SIST EN ISO 62:2009
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SIST EN ISO 62:2009
INTERNATIONAL STANDARD ISO 62:2008(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 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 the determination of the diffusion
coefficient may not be applicable to all plastics. Plastics that do not retain their shape when immersed in
boiling water should not be compared using method 2 (see 6.4).
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 175:1999, Plastics — Methods of test for the determination of the effects of immersion in liquid chemicals
ISO 294-3, Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small plates
ISO 2818, Plastics — Preparation of test specimens by machining
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SIST EN ISO 62:2009
ISO 62:2008(E)
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 periods. The amount of water absorbed by each test
specimen is determined by measuring its change in mass, i.e. the difference between its initial mass and that
after exposure to water, the change being 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.
Relative humidities and temperatures higher than those recommended in this International Standard may be
used by agreement between the 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 also 6.1.3).
4.2 Oven, with forced-air convection or vacuum, maintained at (50,0 ± 2,0) °C or at any other agreed
temperature (see also 6.1.2).
4.3 Containers, containing distilled water or water of equivalent purity, equipped with a means of heating
capable of maintaining the temperature specified.
4.4 Desiccator, with a desiccant (e.g. P O ).
2 5
4.5 Means of measuring the dimensions of the 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 — for example, the notation “none” (no change in appearance) in ISO 175:1999, Table 1. 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 the the water absorption. When determining the moisture
equilibrium content in accordance with 6.3 (method 1) and 6.6 (method 4), the effects of the cleaning agent
can be ignored.
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SIST EN ISO 62:2009
ISO 62:2008(E)
5.2 Square-shaped test specimens for homogeneous plastics
Unless otherwise specified or agreed by all interested parties, the dimensions and dimensional tolerances of
the square-shaped specimens shall be the same as those given in ISO 294-3, with a thickness of
(1,0 ± 0,1) mm. They can be prepared by moulding in accordance with ISO 294-3, 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 the use of
thicker test specimens for the determination of water absorption. In these cases, test specimens of
(2,05 ± 0,05) mm thickness may be used. If specimens of thickness other than 1 mm are used, the specimen
thickness shall be indicated in the test report. There are no requirements for the radii 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, the final dimensions of the specimens may be
beyond the tolerances given in this International Standard, in which case they 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 the reinforcing material may produce erroneous results when small specimens are used. Where
this is of concern, test specimens that meet one of the following types of specimen 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 satisfy the relation:
w u 100d
where
w is the nominal length of one side, in millimetres;
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 out 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.
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SIST EN ISO 62:2009
ISO 62:2008(E)
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 off 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 off 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
⎯ has a length and width of (61 ± 1) mm and has the same shape (thickness and curvature) as the material
being tested.
The machining conditions used to prepare the test specimens shall be agreed by all interested parties. They
shall also be in accordance with ISO 2818 and shall be included in the test report.
If the nominal thickness is greater than 1,1 mm and in the absence of special provisions concerning the
relevant application, the thickness of the test specimens shall be reduced to 1,0 mm to 1,1 mm by machining
on one surface only.
When the surface of a laminate is machined, the water absorption properties will be influenced to such an
extent that the test results will not be valid. Therefore, the specimens shall be tested at their original thickness
and the dimensions shall be indicated in the test report.
6 Test conditions and procedures
6.1 General
6.1.1 Certain materials may require that the test specimens be weighed in a weighing vessel.
6.1.2 Drying procedures other than those described in 6.3 to 6.6 may be used by agreement between the
interested parties.
6.1.3 When the water absorption of the material is greater than or equal to 1 %, specimens which have
been weighed accurately to ± 1 mg and whose mass is constant to ± 1 mg are acceptable.
6.2 General conditions
6.2.1 Specimens shall be carefully dried prior to testing. At 50 °C, for instance, a drying period of between
one and ten days will be necessary, the exact duration depending on the thickness of the specimens.
6.2.2 Use at least 8 ml of distilled water per square centimetre of the total surface of the test specimen but
not less than 300 ml per test specimen. This will prevent any extraction product from becoming excessively
concentrated in the water during the test.
6.2.3 Place each set of three test specimens in a separate container (4.3) and completely immerse them in
water or expose them to 50 % RH (method 4).
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SIST EN ISO 62:2009
ISO 62:2008(E)
When several samples of the same composition are to be tested, the test specimens may be placed together
in the same container with at least 300 ml of water per test specimen. However, in this case, significant
surface contact between test specimens or with the walls of the container is unacceptable and shall be
prevented.
NOTE Grids made of stainless steel may help to ensure an acceptable distance between the test specimens.
For specimens having a density lower than that of water, immerse the specimens by placing them in a
stainless-steel wire basket connected to an anchor-weight by a stainless-steel wire. Avoid surface contact of
the anchor-weight with the specimens.
6.2.4 Time intervals for water immersion are given in 6.3 and 6.4. However, longer immersion periods may
be used by agreement between the interested parties. In such cases, the following precautions shall be taken:
⎯ for tests performed in water at 23 °C, agitate the water at least once daily, for example by swirling the
contents of the container;
⎯ for tests performed in boiling water, add boiling water as required in order to maintain the volume.
6.2.5 During weighing operations, the specimens shall not absorb or release any water. They shall
therefore be weighed immediately after being taken from the exposure environment (and, if necessary,
removing any surface water). Special care shall be taken in the case of thin specimens and materials with a
high coefficient of diffusion for water.
6.2.6 In the case of 1 mm thick specimens and materials with a high coefficient of diffusion for water, the
first weighings shall be carried out after 2 h and 6 h.
6.3 Method 1: Determination of amount of water absorbed after immersion in water at 23 °C
Dry all replicate test specimens in an oven (4.2) maintained at (50 ± 2) °C for at least 24 h (see 6.2.1) and
allow them to cool to room temperature in the desiccator (4.4) before weighing them to the nearest 0,1 mg.
Repeat this process until the mass of the specimens is constant (mass m ) to within ± 0,1 mg.
1
Then place the test specimens in a container (4.3) filled with distilled water maintained at 23,0 °C ± 1,0 °C
or ± 2,0 °C, depending on the relevant specification. In the absence of a specification, the tolerance shall
be ± 1,0 °C.
After immersion for (24 ± 1) h, take the test specimens from the water and remove all surface water with a
clean, dry cloth or with filter paper. Reweigh the test specimens to the nearest 0,1 mg within 1 min of
removing them from the water (mass m ).
2
The water content at saturation is measured by re-immersing the test specimens and reweighing them at
given time intervals. A typical immersion time scale is 24 h, 48 h, 96 h, 192 h, etc. At each of these intervals
(± 1 h), remove the test specimens from the water, remove all surface water and reweigh each test specimen
to the nearest 0,1 mg within 1 min of removing them from the water (e.g. m ).
2/24 h
6.4 Method 2: Determination of amount of water absorbed after immersion in boiling water
Dry all replicate test specimens in an oven (4.2) maintained at (50,0 ± 2,0) °C for at least 24 h (see 6.2.1) and
allow them to cool to room temperature in the desiccator (4.4) before weighing them to the nearest 0,1 mg.
Repeat this process until the mass of the specimens is constant (mass m ) to within ± 0,1 mg.
1
Then place the test specimens in a container (4.3) of boiling distilled water so that they are supported on one
edge and entirely immersed. After (30 ± 2) min, remove the test specimens from the boiling water and cool
them in distilled water maintained at room temperature. After cooling the test specimens for (15 ± 1) min,
remove them from the water one at a time. Remove all surface water with a dry cloth, then immediately weigh
them to the nearest 0,1 mg (mass m ). If the thickness of the test specimens is less than approximately
2
1,5 mm, a small but measurable amount of
...
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