1、PD ISO/TR 19716:2016 Nanotechnologies Characterization of cellulose nanocrystals BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06PD ISO/TR 19716:2016 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of ISO/TR 19716:2016. The UK p
2、articipation in its preparation was entrusted to Technical Committee NTI/1, Nanotechnologies. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsi
3、ble for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 90974 0 ICS 07.030 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standa
4、rds Policy and Strategy Committee on 31 May 2016. Amendments issued since publication Date Text affectedPD ISO/TR 19716:2016 ISO 2016 Nanotechnologies Characterization of cellulose nanocrystals Nanotechnologies Caractrisation des nanocristaux de cellulose TECHNICAL REPORT ISO/TR 19716 Reference numb
5、er ISO/TR 19716:2016(E) First edition 2016-05-01PD ISO/TR 19716:2016ISO/TR 19716:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise
6、 in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch.
7、de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgPD ISO/TR 19716:2016ISO/TR 19716:2016(E)Foreword iv Introduction v 1 Scope . 1 2 T erms and definitions . 1 3 Symbols and abbreviated terms . 2 4 Production of cellulose
8、 nanocrystals (CNCs) 3 5 Composition 6 5.1 Chemical composition 6 5.2 Surface functional groups 7 5.2.1 Determination of sulfate half-esters . 7 5.2.2 Determination of carboxylic acids .11 5.3 Degree of polymerization .12 5.4 Crystallinity . 13 5.4.1 General.13 5.4.2 X-ray diffraction .14 5.4.3 Nucl
9、ear magnetic resonance 16 5.4.4 Vibrational spectroscopy .18 5.4.5 Crystallinity measurements for CNCs .18 5.5 Moisture content 20 5.6 Contaminants 20 5.6.1 General.20 5.6.2 Residual impurities derived from cellulosic biomass .21 5.6.3 Metal ions 21 5.6.4 Detection of contaminants by X-ray photoelec
10、tron spectroscopy .21 6 CNC Morphology .22 6.1 Distributions of length and cross-section from microscopy 22 6.1.1 General.22 6.1.2 Electron microscopy 23 6.1.3 Atomic force microscopy .25 6.1.4 Image analysis considerations 27 6.1.5 Microscopy size distributions for CNCs 27 6.2 Size measurement by d
11、ynamic light scattering (DLS) .31 7 CNC Surface characteristics 33 7.1 Specific surface area 33 7.2 Surface charge 34 8 Miscellaneous .35 8.1 Thermal properties 35 8.2 Viscosity .38 9 Concluding comments 38 Bibliography .40 ISO 2016 All rights reserved iii Contents PagePD ISO/TR 19716:2016ISO/TR 197
12、16:2016(E) 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 fo
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18、ntary information The committee responsible for this document is ISO/TC 229, Nanotechnologies.iv ISO 2016 All rights reservedPD ISO/TR 19716:2016ISO/TR 19716:2016(E) Introduction Cellulose nanomaterials, including cellulose nanocrystals (CNCs) and cellulose nanofibrils, are anticipated to have signi
19、ficant commercial impact. Cellulose nanocrystals are extracted from naturally occurring cellulose, primarily from wood and annual plants, by acid hydrolysis, or chemical or enzymatic oxidation. 123Their production from cellulose sources, such as wood pulps makes them a candidate for use as a potenti
20、ally non-toxic, biodegradable and sustainable nanomaterial. Furthermore, the recent demonstration of the feasibility of CNC production on a large scale and the availability of infrastructure for harvesting raw materials will facilitate their commercial development. CNCs and cellulose nanofibrils are
21、 produced in a number of countries on pilot, pre-commercial or commercial scales. Estimates of the market potential for cellulosic nanomaterials are as high as 35 million metric tons annually, depending on the predicted applications and the estimated market penetration. 45Standards for characterizat
22、ion of CNCs are required for material certification to allow sustained commercial development and applications. Cellulose nanocrystals are nanorods that have high aspect ratio, surface area and mechanical strength and assemble to give a chiral nematic phase with unique optical properties. They are s
23、maller than cellulose nanofibrils and have a higher crystalline content. These properties, plus the ability to control CNC surface charge and chemistry for dispersion in a variety of matrices, lead to potential applications in many areas including nanocomposite materials, paints and adhesives, optic
24、al films and devices, rheology modifiers, catalysts and biomedical products. There are currently no International Standards for this emerging commercial nanomaterial, although an ISO/TC 229 project on terminology is in progress, a Canadian National Standard (CSA Z5100) was published in 2014 and two
25、CNC reference materials were released in 2013. This Technical Report reviews information on sample preparation, data collection and data analysis/interpretation for the measurands that are predicted to be important for the development of commercial products containing CNCs. Information for the follo
26、wing CNC properties is included: composition (crystallinity, surface functional groups, degree of polymerization and contaminants), morphology as assessed by microscopy and light scattering methods, surface charge and specific surface area, viscosity and thermal stability. The Technical Report revie
27、ws various approaches that have been used for specific properties, but does not recommend standard methods or provide detailed information on the techniques. The coverage is restricted to CNCs as produced and does not extend to post-production modified CNCs or CNC-enhanced materials or products. ISO
28、 2016 All rights reserved vPD ISO/TR 19716:2016PD ISO/TR 19716:2016Nanotechnologies Characterization of cellulose nanocrystals 1 Scope This Technical Report reviews commonly used methods for the characterization of cellulose nanocrystals (CNCs), including sample preparation, measurement methods and
29、data analysis. Selected measurands for characterization of CNCs for commercial production and applications are covered. These include CNC composition, morphology and surface characteristics. 2 T erms a nd definiti ons For the purposes of this document, the following terms and definitions apply. 2.1
30、agglomerate collection of weakly or medium strongly bound particles where the resulting external surface area is similar to the sum of the surface areas of the individual components Note 1 to entry: The forces holding an agglomerate together are weak forces, for example, van der Waals forces or simp
31、le physical entanglement. Note 2 to entry: Agglomerates are also termed secondary particles and the original source particles are termed primary particles. SOURCE: ISO/TS 80004-2:2015, 3.3 2.2 aggregate particle comprising strongly bonded or fused particles where the resulting external surface area
32、is significantly smaller than the sum of surface areas of the individual components Note 1 to entry: The forces holding an aggregate together are strong forces, for example, covalent bonds, or those resulting from sintering or complex physical entanglement, or otherwise combined former primary parti
33、cles. Note 2 to entry: Aggregates are also termed secondary particles and the original source particles are termed primary particles. SOURCE: ISO/TS 80004-2:2015, 3.4 2.3 nanocrystal nano-object with a crystalline structure SOURCE: ISO/TS 80004-2:2015, 4.15 2.4 n a no f ibr e nano-object with two ex
34、ternal dimensions in the nanoscale and the third dimension significantly larger Note 1 to entry: The largest external dimension is not necessarily in the nanoscale. Note 2 to entry: The terms nanofibril and nanofilament can also be used. TECHNICAL REPORT ISO/TR 19716:2016(E) ISO 2016 All rights rese
35、rved 1PD ISO/TR 19716:2016ISO/TR 19716:2016(E) 2.5 nano-object discrete piece of material with one, two or three external dimensions in the nanoscale Note 1 to entry: The second and third external dimensions are orthogonal to the first dimension and to each other. SOURCE: ISO/TS 80004-2:2015, 2.2 2.
36、6 nanorod solid nanofibre SOURCE: ISO/TS 80004-2:2015, 4.7 2.7 nanoscale size range from approximately 1 nm to 100 nm Note 1 to entry: Properties that are not extrapolations from a larger size will typically, but not exclusively, be exhibited in this size range. For such properties the size limits a
37、re considered approximate. Note 2 to entry: The lower limit in this definition (approximately 1 nm) is introduced to avoid single and small groups of atoms from being designated as nano-objects or elements of nanostructures, which might be implied by the absence of a lower limit. SOURCE: ISO/TS 8000
38、4-2:2015, 2.1 3 Symbols and abbreviated terms For the purposes of this document, the following symbols and abbreviated terms apply. AEC anion-exchange chromatography AFM atomic force microscopy BET Brunauer-Emmett-Teller (method for determination of specific surface area) CrI crystallinity index (al
39、so CI) CNC(s) cellulose nanocrystal(s) CP-MAS cross polarization magic angle spinning d h hydrodynamic diameter DP degree of polymerization D t translational diffusion coefficient DSC differential scanning calorimetry DLS dynamic light scattering dielectric constant EM electron microscopy FE-SEM fie
40、ld emission-scanning electron microscopy FTIR Fourier transform infrared spectroscopy2 ISO 2016 All rights reservedPD ISO/TR 19716:2016ISO/TR 19716:2016(E) GLC gas-liquid chromatography ICP-MS inductively coupled plasma-mass spectrometry ICP-OES inductively coupled plasma-optical emission spectrosco
41、py ID isotope dilution IR infrared k Boltzmann constant PI polydispersity ssNMR solid state nuclear magnetic resonance SEC size exclusion chromatography SEM scanning electron microscopy TEM transmission electron microscopy TEMPO 2,2,6,6-tetramethyl-1-piperidinyloxy free radical TGA thermogravimetric
42、 analysis U E electrophoretic mobility viscosity XPS X-ray photoelectron spectroscopy XRD X-ray diffraction 4 Production of cellulose nanocrystals (CNCs) Cellulose is a linear polysaccharide composed of anhydroglucose units linked by an oxygen atom between the C1 and C4 carbons of adjacent glucose r
43、ings. In cellulose biosynthesis individual, polysaccharide chains are assembled by an enzyme complex into an elementary fibril with stacked chains held together by hydrogen bonding. The number and organization of polymer chains is specific to the organism. These elementary fibrils are further assemb
44、led to give larger structures that contain ordered (crystalline), as well as disordered cellulose and other components that depend on the organism. Cellulose nanocrystals are formed from one or more elementary fibrils and contain primarily crystalline and paracrystalline regions. CNCs have length an
45、d cross-sectional dimensions that depend on the cellulose source with typical aspect ratios between 5 and 50 and do not exhibit branching or network-like structures. The term nanocrystalline cellulose is synonomous with CNCs and the term nanowhiskers has also been used frequently in the literature.
46、Cellulose nanofibrils are typically larger than CNCs and are branched, entangled and agglomerated structures. The nanofibrils have crystalline, paracrystalline and amorphous regions and can contain non-cellulosic components. They have cross- sections between 5 nm and 50 nm and aspect ratios that are
47、 greater than 50. An ISO/TC 229 project 6aimed at standardizing the terminology for cellulose nanomaterials has recently been initiated. Cellulose nanocrystals are produced from a variety of cellulose sources, primarily wood and other plants, but also algae, bacteria and tunicates. 2378910111213Thei
48、r extraction from cellulose- containing biomass begins with mechanical and/or chemical pre-treatment to remove non-cellulose components, reduce the particle size and increase the exposed surface area. This is followed by a hydrolysis or oxidation step that digests the more reactive amorphous cellulo
49、se and liberates CNCs from the larger cellulose fibrils (Figure 1). Acid hydrolysis with sulfuric acid is the most widely used method for CNC production in both research laboratories and pilot scale commercial facilities, although other ISO 2016 All rights reserved 3PD ISO/TR 19716:2016ISO/TR 19716:2016(E) acids (e.g. hydrochloric, phosphoric, phosphotungstic) have also been employed. 237891415In attempts to minimize the use of strong acids, a variety of other processes have also been exa
