Plastics - Determination of ash - Part 1: General methods (ISO 3451-1:1997)

Kunststoffe - Bestimmung der Asche - Teil 1: Allgemeine Grundlagen (ISO 3451-1:1997)

Dieser Teil von ISO 3451 beschreibt die allgemeinen Grundlagen sowie geeignete Prüfbedingungen zur Bestimmung der Asche für eine Reihe von Kunststoffen (Polymere und Formmassen). Spezielle Prüfbedingungen können in den Formmasse- Normen oder sonstigen Materialspezifikationen vereinbart werden.  Spezielle Prüfbedingungen für glasfaserverstärkte Kunststoffe, Füllstoffe und/oder bestimmte Zusatzstoffe werden in den weiteren Teilen der ISO 3451 festgelegt, die sich jeweils auf bestimmte Kunststoff-Typen beziehen.

Plastiques - Détermination du taux de cendres - Partie 1: Méthodes générales (ISO 3451-1:1997)

Polimerni materiali - Določevanje pepela - 1. del: Splošne metode (ISO 3451-1:1997)

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SIST EN ISO 3451-1:2000

Plastics - Determination of ash - Part 1: General methods (ISO 3451-1:1997)
Kunststoffe - Bestimmung der Asche - Teil 1: Allgemeine Grundlagen (ISO 3451-1:1997)
Plastiques - Détermination du taux de cendres - Partie 1: Méthodes générales (ISO 3451
Ta slovenski standard je istoveten z: EN ISO 3451-1:1997
83.080.01 Polimerni materiali na Plastics in general
SIST EN ISO 3451-1:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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Third edition
1997-07- 15
Plastics - Determination of ash -
Part 1:
General methods
Plastiques - D&termination du taux de cendres -
Partie 1: Mkthodes g&Wales
Reference number
IS0 3451=1:1997(E)

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IS0 3451=1:1997(E)
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
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. IS0
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 IS0 3451-l was prepared by Technical Committee
ISOAC 61, Plastics, Subcommittee SC 5, Physical-chemical properties.
This third edition cancels and replaces the second edition (IS0 3451-1 :1981),
which has been technically revised. The main change is the inclusion of a
precision clause (clause 8).
IS0 3451 consists of the following parts, under the general title Plastics -
Determination of ash:
- Part 1: General methods
- Part 2: Polyakylene terephthalates
Part 3: llnplasticized cellulose acetate
- Par? 4: Polyamides
- Part 5: Poly(vinyl chloride)
0 IS0 1997
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 l CH-1211 Geneve 20 l Switzerland
Internet central @
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland

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Plastics - Determination of ash -
Part 1:
General methods
1 Scope
This part of IS0 3451 specifies general methods, with suitable test conditions, for the determination of the ash of a
range of plastics (resins and compounds). The particular conditions chosen may be included in the specifications for
the plastic material in question.
Particular conditions applicable to plastics containing glass fibre reinforcement, fillers and/or certain additives are
specified in further parts of IS0 3451 pertaining to specific types of plastics (see foreword).
2 Principle
It is possible to determine the ash of an organic material by three main methods:
a) Direct calcination, i.e. by burning the organic matter and heating the residue at high temperature until constant
mass is reached (method A).
Calcination after sulfation, which may be carried out by two different procedures:
- With sulfuric acid treatment after burning, i.e. by burning the organic matter, transforming the inorganic
residue into sulfates with concentrated sulfuric acid and heating the residue at high temperature until
constant mass is reached. This is the common method of obtaining “sulfated ash” (method B).
- With sulfuric acid treatment before burning, i.e. by heating the organic matter together with concentrated
sulfuric acid up to temperatures where fuming and subsequent burning of the organic matter occur, and
finally heating the residue at high temperature until constant mass is reached (method C). This procedure
may be used if volatile metal halides are liable to evaporate during burning of the organic matter. It is not
applicable to silicones or fluorine-containing polymers.
In each case, the final step of the procedure is calcination at 600 OC, 750 OC, 850 OC or 950 OC until constant mass
is reached (see 5.2).
3 Reagents (for methods B and C only)
During the analysis, use only reagents of analytical grade and only distilled water or water of equivalent purity.
3.1 Ammonium carbonate, anhydrous.
Ammonium nitrate, approximately 10 % (mlm) solution.

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@ IS0
IS0 3451=1:1997(E)
3.3 Sulfuric acid, p = 1,84 g/cm?
WARNING - Care should be taken in handling.
3.4 Sulfuric acid, 50 % (V/V) solution.
WARNING - Care should be taken in handling.
4 Apparatus
4.1 Crucible, made of silica, porcelain or platinum, inert to the material tested.
4.2 Gas burner, or other appropriate heat source.
4.3 Muffle furnace or microwave furnace, capable of being maintained at 600 OC + 25 OC, 750 OC + 50 OC,
850 OC rfi 50 OC or 950 OC * 50 OC as
4.4 Analytical balance, accurate to 0,l mg.
4.5 Pipettes, of suitable capacity (for methods B and C only).
4.6 Desiccator, containing an efficient desiccant which does not interact with the ash.
NOTE - In certain cases, the ash may have a greater affinity for water than some substances commonly used as desiccants.
4.7 Weighing bottle.
4.8 Fume cupboard.
5 Procedure
5.1 Test portion
Take a quantity of the test sample sufficient to yield 5 mg to 50 mg of ash. If the likely quantity of ash is unknown,
carry out a preliminary determination.
Recommended test portion sizes are given in table 1.
- Recommended size of test portion
Table 1
Approximate ash
Mass of ash obtained
Test portion
(if known)
200 min. 5to50
s 0,Ol
> 0,Ol to 0,05
25 to 50
> 0,05to 0,l 50
25 25 to 50
> 0,l to 0,2
> 0,2 10 max.

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@ IS0
IS0 3451=1:1997(E)’
For plastics yielding very low ash, it is necessary to use large test portions. When it is impossible to burn the whole
of the test portion at one time, weigh the required quantity in a suitable weighing bottle and introduce it into the
crucible (4.1) in convenient amounts for a succession of burnings until the whole of the test portion has been burnt.
5.2 Test conditions
Calcination shall be continued to constant mass as defined in 53.6, but the duration of the calcination in the muffle
furnace (4.3) shall not exceed 3 h at the specified temperature.
The choice of the calcination temperature and the use of the sulfation method depend on the nature of the plastic
and any additives it may contain. If a choice exists between different satisfactory conditions, choose those which
allow the attainment of constant mass in less than 3 h. A higher temperature or the use of sulfation generally
shortens the duration of the calcination.
Whichever method -A, 6 or C - is used, choose on

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