ISO 6031:2025

International
Standard
ISO 6031
First edition
Functional extenders for special
2025-07
application — Nanoscale diamonds
for polymer composites
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Classification and designation . 3
5.1 Classification .3
5.2 Designation .3
6 Requirements and test methods . 4
6.1 Appearance .4
6.2 Technical requirements and test methods .4
7 Sampling . 5
8 Marking and labelling . 5
9 Test report . 6
Annex A (informative) Examples of basic characteristics and test methods of nanoscale
diamonds in liquid or solid dispersion . 7
Bibliography . 8

iii
Foreword
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iv
Introduction
Diamond is a solid carbon material with a cubic crystal structure, within which each atom is covalently
bonded to four neighbouring atoms forming a regular tetrahedron. This dense packing of carbon atoms
determines the following unique properties of diamond:
— the highest hardness and wear resistance,
— the highest thermal conductivity and high electrical resistivity,
— high refractive index and wide band gap,
— chemical and radiation resistance,
— high biocompatibility.
Nanoscale diamonds, also called nanodiamonds or ultradispersed diamonds, were first discovered in the
Soviet Union in 1963 in a detonation blend obtained by the explosion of a trotyl-hexogen charges in a big,
closed metal detonation chamber in air environment without any additional carbon source. Since then, they
[4][5][6]
have been carefully studied and have become commercially available. At the time of publication of
this document, nanodiamonds are obtained by the detonation of explosives, by laser-induced synthesis from
carbon soot, as well as by crushing and milling microdiamonds. Their main industrial applications include
fine polishing and lapping, antifriction lubrication and electroplating. They are also used as functional
additives to varnishes, paints and adhesives, thermal compounds and other composite materials.
Nanoscale diamonds have an average primary particle size of less than 100 nm. In case of detonation or laser
synthesis, most of them are smaller than 10 nm while their average size usually does not exceed 5 nm. Unlike
ordinary diamonds, a single nanodiamond particle has a complex structure, consisting of an inert diamond
core and a reactive shell of hybrid fullerene-like or amorphous carbon with various functional groups on the
surface (carbonyl, carboxyl, hydroxyl, amine, amide, ether, etc.). Nanodiamonds have a large surface area (up
2 3
to 600 m /g) and a low bulk density (up to 1 g/cm ). They usually aggregate strongly, forming agglomerates
several micrometres in size.
Ready-to-use functional nanodiamond extenders can be supplied in the form of a powder with specially
modified surface that provides disaggregation of nanodiamonds when they are introduced into a specific
production process and mixed. In addition, functional extenders can be supplied in the form of concentrated
dispersions of disaggregated nanodiamonds based on solvents, polymer resins and plastics.
To be used as a functional extender for application in polymer composites, nanoscale diamonds are provided
in powder form or disaggregated and uniformly distributed in a polymer matrix or in a liquid.
Nanoscale diamond uniformly dispersed in polymers can improve polymers in terms of their strength, wear
resistance, flexibility, thermal conductivity, thermal stability, radiation resistance and other functional
properties.
v
International Standard ISO 6031:2025(en)
Functional extenders for special application — Nanoscale
diamonds for polymer composites
1 Scope
This document specifies requirements and corresponding test methods for nanoscale diamond as a
functional additive in polymer composites.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 787-9, General methods of test for pigments and extenders — Part 9: Determination of pH value of an
aqueous suspension
ISO 3262-1, Extenders — Specifications and methods of test — Part 1: Introduction and general test methods
ISO 4618, Paints and varnishes — Vocabulary
ISO 9277, Determination of the specific surface area of solids by gas adsorption — BET method
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 18451-1, Pigments, dyestuffs and extenders — Terminology — Part 1: General terms
ISO 80004-1, Nanotechnologies – Vocabulary — Part 1: Core vocabulary
IEC/TS 62607-4-6, Nanomanufacturing — Key control characteristics — Part 4-6: Nano-enabled electrical energy
storage — Determination of carbon content for nano-enabled electrode materials, infrared absorption method
IEC/TS 62607-6-13, Nanomanufacturing — Key control characteristics — Part 6-13: Graphene-based
material — Oxygen functional group content: Boehm titration method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618, ISO 18451-1, ISO 80004-1
and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
nanoscale diamonds
nanodiamonds
engineered carbon nanomaterials with cubic crystalline structure
...