ISO 23832:2021

INTERNATIONAL ISO
STANDARD 23832
First edition
2021-06
Plastics — Test methods for
determination of degradation
rate and disintegration degree of
plastic materials exposed to marine
environmental matrices under
laboratory conditions
Plastiques — Méthodes d'essai pour l'évaluation de la vitesse de
dégradation et du degré de désintégration des matériaux plastiques
exposés aux matrices environnementales marines dans des conditions
de laboratoire
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 3
6 Environmental matrix . 3
6.1 Sampling . 3
6.2 Preparation of the sediment and seawater . 4
7 Apparatus . 4
8 Materials . 6
8.1 Test material . 6
8.2 Reference material . 6
8.3 Negative control . 6
9 Sample preparation and measurements . 7
9.1 Acclimatisation of samples . 7
9.2 Conditioning before measurements . 7
9.3 Marking of samples . 7
9.4 Protective net . 7
9.5 Tensile properties . 7
9.6 Thickness . 8
10 Test set-up . 8
10.1 Incubation . 8
10.2 Sampling times and replicates . 8
10.3 Start of the test . 8
10.3.1 General. 8
10.3.2 Test Method A (sand burial degradation test) . 9
10.3.3 Test method B (sediment/seawater interface degradation test) . 9
10.3.4 Test method C (Seawater degradation test) .10
10.4 End of the test .10
11 Degradation rate .10
12 Degree of disintegration .11
12.1 General .11
12.2 Surface area analysis .11
12.3 Mass loss .11
13 Validity of the test .12
14 Test report .12
Annex A (informative) Determination of degradation rate — Example .13
Bibliography .15
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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electrotechnical standardization.
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different types of ISO documents should be noted. This document was drafted in accordance with the
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 14,
Environmental aspects.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv © ISO 2021 – All rights reserved

Introduction
Plastics are potentially susceptible to ultimate biodegradation, i.e. to be decomposed by the actions
of microorganisms under aerobic conditions into CO , water and biomass as can be proven with
specific test methods. In most cases, biodegradation occurs at the surface of the plastics materials, i.e.
at the solid-liquid interface. Microbes and enzymes cannot penetrate the solid plastic item, thus only
the exposed surface is generally available to biodegradation. The physical effect of biodegradation
on a solid plastic item is erosion leading to a thinning and weakening of the item. This process leads
the item to lose mass, physical properties, and ultimately physical integrity by fragmentation into
biodegradable particles whose ultimate fate is to be biodegraded. The term disintegration is used
when the degradation process is extended until a total fragmentation of the original item into particles
below a defined size is reached. When microorganisms cause degradation processes biodegradation,
biofragmentation, biodisintegration are the proper terms, etc. as suggested by CEN/TR 15351. However,
when the physical breakdown rather than the chemical breakdown is measured, the generic term
“degradation” is preferably used, reserving the term “biodegradation” to the assessment of the ultimate
biodegradation, i.e. the conversion into CO , H O and biomass.
2 2
The assessment of specific degradation rates occurring when plastics materials are exposed to marine
matrices is needed for designing products intended for marine applications (e.g. biodegradable plastic
fish and mussel farming, floating devices) and for assessment of the risk caused by leakage of products
into the sea.
In this document three test methods for testing degradation are described. Plastics samples can be
exposed to three different test conditions and different marine matrices:
— buried into a wet sandy marine sediment;
— at the interface between a marine sandy sediment and the water column;
— to seawater.
The conditions applied in these test methods are designed to determine the degradation rates of
plastics materials and give an indication of their propensity to physical degradation and disintegration
in natural environments.
Degradation rates considered in this document are mass loss rate, erosion rate, and mechanical
properties loss. Disintegration, i.e. physical breakdown of a sample into very small fragments (<2mm),
can also be assessed.
INTERNATIONAL STANDARD ISO 23832:2021(E)
Plastics — Test methods for determination of degradation
rate and disintegration degree of plastic materials exposed
to marine environmental matrices under laboratory
conditions
1 Scope
This document specifies test methods for the measurement of the physical degradation of samples made
with plastics materials when exposed to marine environmental matrices under aerobic conditions at
laboratory scale.
This document is not suitable for the assessment of degradation caused by hea
...