ISO/TS 21236-1:2019

TECHNICAL ISO/TS
SPECIFICATION 21236-1
First edition
2019-10
Nanotechnologies — Clay
nanomaterials —
Part 1:
Specification of characteristics and
measurement methods for layered
clay nanomaterials
Nanotechnologies — Nano argiles —
Partie 1: Spécification des caractéristiques et des méthodes de mesure
des nano argiles en couches
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 3
5 Characteristics and measurement methods . 4
5.1 General . 4
5.2 Fundamental characteristics . . 4
5.3 Optional characteristics . 5
5.4 Descriptions on characteristics and measurement methods . 6
5.4.1 Chemical composition content . 6
5.4.2 Mineral composition content . 6
5.4.3 Interlayer distance . 7
5.4.4 Thickness . 8
5.4.5 Aspect ratio . 9
5.4.6 Bulk density . 9
5.4.7 Cation exchange capacity . 9
5.4.8 Loss on ignition . 9
5.4.9 Water absorption capacity .10
5.4.10 Moisture content .10
5.4.11 Brightness .10
5.4.12 Colour .10
5.4.13 Methylene blue adsorption capacity .11
5.4.14 Cohesion coefficient .11
5.4.15 Tap density .11
5.4.16 Specific surface area .11
5.4.17 Film formability .12
5.4.18 Electrical resistivity .12
5.4.19 Modifier type .13
6 Reporting .14
6.1 General .14
6.2 Information .14
6.3 Measurement results .14
6.4 Example of table format .14
Annex A (informative) Basic information on layered clay nanomaterials .16
Annex B (informative) Organo-modified layered clay nanomaterials (Organoclay).18
Bibliography .20
Foreword
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iv © ISO 2019 – All rights reserved

Introduction
Layered clay nanomaterials are a subgroup of clay materials with the external dimension (thickness) or
the internal structural dimension (interlayer distance) in the nanoscale. Clay itself, as most important
group of layered nanostructured silicates, refers to naturally occurring or synthetic material composed
primarily of fine-grained minerals, which show plasticity through a variable range of water content
and will harden when fired or dried. The minerals found in clay are generally silicates of less than
2 micrometres in lateral size. Clays are very abundant at the earth's surface; they form rocks known
as shales and are a major component in nearly all sedimentary rocks. The small size of the particles
and their unique crystal structures give clay materials special properties, including cation exchange
[1]
capabilities, plastic behaviour when wet, catalytic abilities, swelling behaviour, and low permeability .
Other than the structure and composition, there are several additional factors which are important in
determining the properties and applications of clays and clay nanomaterials (see Annex A). These are
the mineral impurities, the presence of organic materials, the type and amount of exchangeable ions
[2]
and soluble salts, and the morphological aspects .
Natural and modified clays as layered structured minerals are very important industrial materials.
In pristine form, clay materials are normally subnano spaced layers, structured in bundles and in
exfoliated state; they are nano-objects with thickness in the nanoscale while in intercalated form they
are structured nanomaterials with interlayer space in nanoscale.
Modification of clay with change in its characteristic such as its hydrophobicity, interlayer distance,
exchangeable ion, and surface connected groups leads to the extension of its applications e.g. for high
performance nanocomposites, effective rheological modifier, or biomedical applications. A small
quantity of well dispersed intercalated or exfoliated organo-modified layered clay nanomaterials in
polymeric composites (see Annex B) is proved to show superior impacts on properties such as barrier,
tensile modulus, mechanical strength, and flame retardancy.
There are numerous industrial applications for layered clay nanomaterials. Purified and modified
clays are used as; coatings on paper to enhance whiteness and to allow the proper absorption of ink,
the life time extender of rubber in tires, in concrete, as catalysts in many industries. Moreover, they
can also be used in oil purification, pharmaceuticals, ceramic industry, soil stabilization, porcelains
and barriers for nuclear and chemical wastes because of their cation-exchange capabilities, low
permeability, and long-term structural stability. In addition, layered clay nanomaterials are utilized in
purification industries, in agricultural and food engineering applications, polymeric nanocomposites,
deodorizer, insecticide carrier, pesticides carrier, drilling fluids, desiccant, detergents, plasticizer,
emulsion stabilizer, food additives, cosmetic applications, environmental remediation and many other
[1][2]
miscellaneous applications .
For such a wide range of clay nanomaterial applications, various fundamental characteristics (as
shown in Table 1) play undeniable roles. These characteristics are measured and reported by the
provider of the layered clay nanomaterials. In fact, the determinations of these fundamental and basic
characteristics will facilitate the communication between sellers and buyers of these nanomaterials for
different applications. These characteristics are considered for all industrial layered clay nanomaterial
applications such as nanocomposites, paper, ink, purification, and catalysts. In addition to fundamental
characteristics, presented in Table 1, some other optional characteristics of layered clay nanomaterials
as shown in Table 2 are measured and reported subject to the agreement between sellers and buyers.
...