1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDD ISO/TS 11308:2011Nanotechnologies Characterization of single-wall carbon nanotubes usingthermogravimetric analysisDD ISO/TS 11308:2011 DRAFT FOR DEVELOPMENTNational forewordTh
2、is Draft for Development is the UK implementation of ISO/TS11308:2011.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publicationsand is of a provisional nature. It should be applied on thisprovisional basis, so that information
3、and experience of its practicalapplication can be obtained.Comments arising from the use of this Draft for Developmentare requested so that UK experience can be reported to theinternational organization responsible for its conversion toan international standard. A review of this publication willbe i
4、nitiated not later than 3 years after its publication by theinternational organization so that a decision can be taken on itsstatus. Notification of the start of the review period will be made inan announcement in the appropriate issue of Update Standards.According to the replies received by the end
5、 of the review period,the responsible BSI Committee will decide whether to support theconversion into an international Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sentto the Secretary of the responsible BSI Technical Committee at BritishStandards
6、House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to TechnicalCommittee NTI/1, Nanotechnologies.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the neces
7、saryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 61388 3ICS 07.030Compliance with a British Standard cannot confer immunity fromlegal obligations.This Draft for Development was published under the authority ofthe Standards Policy and Strategy Com
8、mittee on 30 November 2011.Amendments issued since publicationDate Text affectedDD ISO/TS 11308:2011Reference numberISO/TS 11308:2011(E)ISO 2011TECHNICAL SPECIFICATION ISO/TS11308First edition2011-11-15Nanotechnologies Characterization of single-wall carbon nanotubes using thermogravimetric analysis
9、 Nanotechnologies Caractrisation des nanotubes en carbone monofeuillet par analyse thermogravimtrique DD ISO/TS 11308:2011ISO/TS 11308:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
10、or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47
11、 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedDD ISO/TS 11308:2011ISO/TS 11308:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and definitions . 1 4 Abbreviated terms . 2
12、5 Principles of TGA 2 5.1 Measurement . 2 5.2 Exothermic and endothermic reactions 3 6 Sampling 3 6.1 Sample pan selection 3 6.2 Sample size 3 6.3 Sample compaction . 3 7 Test method . 4 8 Data interpretation and results 5 8.1 General . 5 8.2 Non-carbon content 5 8.3 Constituents . 5 8.4 Thermal sta
13、bility 5 8.5 Homogeneity 5 8.6 Purity . 6 8.7 Quality. 6 9 Uncertainties 6 10 Test report 6 Annex A (informative) Case studies 8 Annex B (informative) Effects of operating parameters on TGA analysis 17 Bibliography 20 DD ISO/TS 11308:2011ISO/TS 11308:2011(E) iv ISO 2011 All rights reservedForeword I
14、SO (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 c
15、ommittee 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 electr
16、otechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the m
17、ember bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of doc
18、ument: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) repres
19、ents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revise
20、d to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or be withdrawn. Attention is drawn to the possibility that some of the elements of
21、 this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 11308 was prepared by Technical Committee ISO/TC 229, Nanotechnologies. DD ISO/TS 11308:2011ISO/TS 11308:2011(E) ISO 2011 All rights reserved vIntroduction Sing
22、le-wall carbon nanotubes (SWCNTs) are an allotropic form of carbon which exhibit unique mechanical, thermal and electronic properties respective to the geometric structure12345. SWCNTs can be synthesized by several different methods, including pulsed laser vaporization, arc discharge, high pressure
23、disproportionation of carbon monoxide, and chemical vapor deposition678. These processes often yield a heterogeneous mixture of SWCNTs and impurities, requiring post-synthesis purification. Commonly observed impurities include other forms of carbon e.g. fullerenes, amorphous carbon, graphitic carbon
24、 and multiwall carbon nanotubes (MWCNTs), as well as residual metallic catalyst nanoparticles. Purification can be accomplished using gaseous, chemical and/or thermal oxidation processes9101112. Thermogravimetric analysis (TGA) is one of a number of techniques that can be used to assess impurity lev
25、els in as-produced and purified samples containing SWCNTs14 to 22. TGA measures changes in mass as a function of temperature and is widely used to assess reaction kinetics associated with structural decomposition, oxidation, corrosion, moisture adsorption/desorption, and gas evolution. By evaluating
26、 the reaction kinetics for a given sample, the relative fraction of different constituents present can be either quantitatively or qualitatively determined. For SWCNT-containing samples, TGA is typically used to quantify the level of non-volatile impurities present (e.g. metal catalyst particles). T
27、GA is also used to assess thermal stability (a measure of the type or types of carbon present). However, TGA alone cannot conclusively quantify the relative fractions of carbonaceous products within the material. Therefore, the information obtained from TGA is used to supplement information gathered
28、 from other analytical techniques in order to achieve an overall purity and quality assessment of a SWCNT-containing sample. Additional uses of TGA include process and quality control23and the characterization of MWCNTs2425262728and few-walled carbon nanotubes29. DD ISO/TS 11308:2011DD ISO/TS 11308:
29、2011TECHNICAL SPECIFICATION ISO/TS 11308:2011(E) ISO 2011 All rights reserved 1Nanotechnologies Characterization of single-wall carbon nanotubes using thermogravimetric analysis 1 Scope This Technical Specification provides guidelines for the characterization of SWCNT-containing samples by the use o
30、f TGA, performed in an air environment. Guidance is provided on purity assessment of SWCNT samples through a quantitative measure of the non-carbon impurity (i.e. metal catalyst) level within the material. In addition, this technique can provide a qualitative assessment of the thermal stability and
31、homogeneity of the SWCNT-containing sample. Additional characterization techniques are required to confirm the presence of SWCNTs and to verify the composition of the metallic impurities present. 2 Normative references The following referenced documents are indispensable for the application of this
32、document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/TS 80004-3, Nanotechnologies Vocabulary Part 3: Carbon nano-objects 3 Terms and definitions For the purposes of this document,
33、 the terms and definitions given in ISO/TS 80004-3 and the following apply. 3.1 primary oxidation temperature temperature at which the most intense peak occurs in the derivative thermogravimetric curve 3.2 thermal stability temperature at which the major carbon component oxidizes in an air (i.e. oxy
34、gen-containing) environment, represented by the primary oxidation temperature 3.3 homogeneity measure of how uniformly distributed all constituents (nanotubes as well as impurities) of SWCNT material are throughout a larger sample, as determined by measuring repeated smaller samples using TGA 3.4 co
35、nstituents different components present in a SWCNT-containing sample NOTE A SWCNT-containing sample is often comprised of different carbon and non-carbon materials and is identified by oxidation peaks in the TGA curve and by residual weight. DD ISO/TS 11308:2011ISO/TS 11308:2011(E) 2 ISO 2011 All ri
36、ghts reserved3.5 monotypic material consisting of only one type of carbon nanomaterial NOTE A typical SWCNT sample is comprised of several types of carbon nanomaterials, including amorphous carbon, fullerenes, SWCNTs and MWCNTs. 3.6 purity measure of the fraction (percentage weight or mass fraction)
37、 of SWCNT within a given sample NOTE TGA alone cannot conclusively quantify the relative fractions of any and all carbonaceous products within the material. It can, however, quantify the level of non-volatile (i.e. metal catalyst) impurities, which is one measure of purity. 3.7 quality measure of th
38、e overall degree of excellence of SWCNT material, established by the level of impurities and the level of structural imperfections or defects to the crystal structure (structural integrity) NOTE 1 TGA can partly contribute to the quality assessment of SWCNT material by providing its residual weight
39、and oxidation temperature. NOTE 2 A SWCNT material may have a high purity level (i.e. a net mass fraction of 100%) but it may have a considerable amount of damage which can alter or destroy its physical properties, thereby deteriorating the quality of the SWCNT material. 4 Abbreviated terms TGA ther
40、mogravimetric analysis TGC thermogravimetric curve (sometimes known as weight loss curve) DTGC derivative thermogravimetric curve (sometimes known as derivative weight loss curve) Toxoxidation temperature Toxprimary oxidation temperature Wresresidual weight of sample after heating DTA differential t
41、hermal analysis DSC differential scanning calorimetry CVD chemical vapor deposition HiPco high pressure CO conversion 5 Principles of TGA 5.1 Measurement When a SWCNT-containing sample is subjected to elevated temperatures in the presence of air, the carbon species present will oxidize into gaseous
42、compounds such as CO or CO2. The residue is comprised of non-volatile materials, which for the most part are metal impurities. DD ISO/TS 11308:2011ISO/TS 11308:2011(E) ISO 2011 All rights reserved 3In principle TGA measures the weight loss of a material as a function of temperature as it is heated.
43、TGA requires the precise measurements of weight, temperature and temperature change. The weight loss of a material is related to the composition of the material. Weight loss relative to an increase in temperature can result from the removal of absorbed moisture, solvent residues, chemically bound mo
44、ieties and/or decomposition of product. TGA alone cannot identify the volatile materials; however, if other analytical equipment such as a mass spectrometer or infrared spectrometer is employed, such information can be obtained. With respect to SWCNT materials, TGA cannot by itself identify the diff
45、erent carbon forms present within the material. However, it can provide a quantitative measure of the non-volatile products and the temperature at which the carbon species oxidize. 5.2 Exothermic and endothermic reactions Many materials can undergo transitions in which heat is absorbed or given off
46、without a change in weight. Such events will result in differences in temperature between the sample and a reference. Many TGA systems are equipped to operate in a DTA or DSC mode, which can provide information on these transitions. SWCNT-containing samples of particular morphologies have been obser
47、ved to undergo combustive reactions resulting in rapid burning of material, which may be catalyzed by residual metals. 6 Sampling 6.1 Sample pan selection Sample pan size and type will vary depending on the type of instrument being used. Other than equipment limitations, there is no restriction on t
48、he sample pan size so long as it is capable of accommodating the required amount of SWCNT material. Larger pan sizes can accommodate SWCNT without need for compaction, which is desirable but might not be accessible for all instruments. Either aluminium or platinum pans can be used under the experime
49、ntal temperature range. Aluminium pans are recommended since they are less likely to catalytically oxidize SWCNTs, which can lead to erroneous data. It is recommended that the pans be conditioned by prior heating to at least 1 000 C in an air environment in order to prevent errors due to oxidation of the pan material during sample analysis. 6.2 Sample size The type of SWCNTs (as-produced versus purified) is the controlling factor in the selection of sample size. As-produced materials can be more
