EN ISO 7822:1999

SLOVENSKI STANDARD
01-maj-2000
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Textile glass reinforced plastics - Determination of void content - Loss on ignition,
mechanical disintegration and statistical counting methods (ISO 7822:1990)
Textilglasverstärkte Kunststoffe - Bestimmung der Menge vorhandener Lunker -
Glühverlust, mechanische Zersetzung und statistische Auswertungsverfahren (ISO
7822:1990)
Plastiques renforcés de verre textile - Détermination de la teneur en vide - Méthodes par
perte au feu, par désintégration mécanique et par comptage statistique (ISO 7822:1990)
Ta slovenski standard je istoveten z: EN ISO 7822:1999
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
83.120 2MDþDQLSROLPHUL Reinforced plastics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ISO
INTERNATIONAL
STANDARD 7822
First edition
1990-09-01
Textile glass reinforced plastics -
Determination of void content - Loss on
ignition, mechanical disintegration and
statistical counting methods
Determination de Ia teneur en vide -
Plastiques renforces de verre textile -
Mthodes par perte au feu, par d&int&gration mkanique et par camptage
statistique
Reference number
ISO 7822 : 1990 (El
ISO 7822 : 1990 (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. Esch 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, govern-
mental and non-governmental, in Iiaison with ISO, also take patt 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 7822 was prepared by Technical Committee ISO/TC 61,
Plastics.
Annex A of this International Standard is for information only.
0 ISO 1990
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
INTERNATIONAL STANDARD ISO 7822 : 1990 (E)
Textile glass reinforced plastics - Determination of void
- Loss on ignition, mechanical disintegration and
content
statistical counting methods
1 Scope 2 Normative references
The following Standards contain provisions which, through
This International Standard specifies three methods for the
reference in this text, constitute provisions of this International
determination of the void content of textile glass reinforced
Standard. At the time of publication, the editions indicated
plastics or composites, of which the constituents are of a solid
were valid. All Standards are subject to revision, and Parties to
nature.
agreements based on this International Standard are encouraged
to investigate the possibility of applying the most recent editions
1.1 Method A - Loss on ignition
of the Standards indicated below. Members of IEC and ISO
maintain registers of currently valid International Standards.
This method is applicable to composites for which the effects
of the loss on ignition test on the materials are known. Most ISO 291: 1977, Plastics - Standard atmospheres for condition-
ing and testing.
matrix resins and textile glass fibre reinforcements fall into this
class.
ISO 1172: 1975, Textile glass reinforced plastics - Determi-
nation of Ioss on ignition.
The method is not applicable to composites for which the ef-
fects of the loss on ignition test on the resin, the reinforcement,
and any fillers are unknown. This may include Silicone resins,
3 Principle
which do not burn off completely, and fillers consisting of ox-
ides, carbonates, etc., which may gain or lose weight. Note
that separate weight loss tests on individual materials will
3.1 Method A - Loss on ignition
usually, but not necessarily, give the same result as when all
Determination of the densities of the resin, the reinforcement,
the materials are combined.
filier(s) (if present) and the composite. Determination of the
resin content and calculation of a theoretical composite den-
The accuracy of the method is +2,5 % by volume.
sity. Comparison with the measured composite density. The
differente in densities indicates the void content.
1.2 Method B - Mechanical disintegration
NOTE - The density of the resin, in this method, is assumed to be the
This method is applicable if the composite tan be disintegrated same in the composite as it is in a moulded mass. Although there is no
realistic way of avoiding having to make this assumption, it is never-
in such a way, for example by crushing in a press, that all the
theless not strictly correct. Differentes in curing, heating, pressure and
enclosed voids are connected with the outside of the com-
molecular forces arising from the reinforcement sutface all make the
posite material. The method is destructive and has limited ap-
density of the resin in the composite different from the bulk resin density.
plication if the matrix material Shows ductile behaviour under
compression, unless it tan be made more brittle in an artificial
Composites containing inorganic fillers require special care. An
way (for example by cooling).
accurate determination of the filler content and density is re-
quired if the accuracy of this method is to be maintained.
The method is especially suitable when the densities of the con-
stituent materials are not known or not determinable.
3.2 Method B - Mechanical disintegration
The method neglects the influence of any volatile constituents
Determination of the mass and volume, before and after
that could evaporate during and after disintegration. In this
disintegration, of a fibre reinforced plastic Sample to obtain the
connection, the conditioning shall be Chosen with care. The
void content by density differente.
method also does not take into account any tut or exposed
voids at the surface of the Sample.
3.3 Method C - Statistical counting
The accuracy of the method is * 1 % by volume.
Superimposition of a Square grid of 20 to 200 Points on a
micrographic section of the material to be tested. Statistically,
the proportion of Points of the grid which are superimposed on
1.3 Method C - Statistical counting
voids corresponds to the void content of the material. The
counting method may be manual, or semi-automatic or auto-
This method is applicable to composites having a void content
less than or equal to 1 % by volume. matic using suitable apparatus.
ISO 7822 : 1990 (El
the preparation of micrographic
4.3.2 Equipment for
4 Apparatus
sections, comprising
4.1 Method A
a) a cutting machine;
b) a polishing machine;
4.1 .l Micrometer, having an accuracy of $11 Fm.
Cl a mould for encasing the section in transparent resin;
4.1.2 Balance, having an accuracy of +O,l mg.
d) an ultrasonic cleaning bath.
Muffle furnace, capable of being maintained at
4.1.3
625 *C k 5 OC. 5 Preparation and number of test specimens
5.1 Methods A and B
4.2 Method B
5.1 .l The test specimens shall be representative of the
4.2.1 Disintegrator (in its simplest form a press), in which
’
composite to be examined. The quantity and form will depend
the test material is delaminated and crushed until all the voids
on the pyknometer and the disintegration procedure used.
are connected with the outside of the composite material. lt is
When an air pyknometer is used, quantities of about 25 g or
advisable, however, to use a closed-die unit made of hardened
12 000 mm3, preferably in the form of Strips about 38 mm long,
steel as shown in figure 1.
about 10 mm wide and of the thickness of the composite, are
needed for each determination.
5.1.2 From the composite to be examined, tut a series of at
least five Strips of appropriate size and mass. The pieces shall
be clean and dry.
5.2 Method C
5.2.1 The specimens shall have the shape of a parallepiped
40 mm long and 10 mm wide, the thickness depending on the
thickness of the structure from which the specimens have been
tut, with a maximum value of 15 mm. The number of specimens
to be taken will depend on the number of sections needed and
on the nature of the structure to be tested; each specimen tan
give several sections.
Sample
5.2.2 Prepare a total of at least five sections from among the
specimens. The polishing Operation and the encasing of the
sections in cold-curing resin shall be carried out in accordance
Figure 1 - Disintegration die
with the procedures used in micrography. (See annex A.)
4.2.2 Air or gas pyknometer, suitable for measuring the
6 Atmospher
...