ISO/TS 23690:2023 ナノテクノロジー — 多層カーボンナノチューブ — 熱重量分析による炭素不純物含有量の測定 | ページ 2

3.1 用語と定義

この文書の目的上、次の用語と定義が適用されます。

ISO と IEC は、標準化に使用する用語データベースを次のアドレスで維持しています。

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. 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. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives ).

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This document was prepared by Technical Committee ISO/TC 229, Nanotechnologies.

Introduction

Multiwall carbon nanotubes (MWCNTs) are quasi-one-dimensional tubular carbon nanomaterials rolled up or coaxial nested by three or more graphene sheets. The production of carbon nanotubes (CNT) generally results in significant amounts of carbon impurities (carbon material content not in the form of CNT, including amorphous carbon and trace amounts of other types of structured carbon), which influence the physical and chemical properties of the nanomaterial. Therefore, the measurement of carbon impurities content in MWCNT samples is highly desirable for the determination of their purity.

Several methods have been reported to characterize carbon impurities in MWCNT samples, including transmission electron microscopy (TEM), temperature programmed oxidation (TPO) and thermogravimetric analysis (TGA), etc., among which TGA can provide quantitative results.^{[1][2][3][4][5][6]} This technique makes use of the fact that MWCNTs are more stable than the majority of carbon impurities, so carbon impurities less stable than MWCNTs will react firstly with carbon dioxide in carbon dioxide atmosphere. The oxidation of carbon impurities with carbon dioxide is an endothermal process, which prevents overheating in certain areas and restrains the reaction of MWCNTs at the same time. Therefore, the separation between the oxidation of carbon impurities and those of MWCNTs is enhanced,^{[7][8][9][10]} allowing the amount of carbon impurities less stable than MWCNTs to be calculated from the mass loss in thermogravimetric analysis.

1 Scope

This document specifies a mild oxidation method to determine the content of carbon impurities (carbon material content not in the form of CNT, including amorphous carbon and trace amountd of other types of structured carbon) less stable than multiwall carbon nanotubes (MWCNTs) by thermogravimetric analysis (TGA) under carbon dioxide atmosphere.

This document is applicable to the characterization of carbon impurities content in MWCNT samples prepared by chemical vapour deposition (CVD). Measurement of carbon impurities in MWCNT samples prepared by other methods can refer to this document. This method is not applicable to functionalized MWCNT samples or MWCNT samples with encapsulant species.

2 Normative references

There are no normative references in this document.

3 Terms, definitions and abbreviated terms

3.2 Symbols

3.3 Abbreviated terms

Bibliography