ISO 21400:2018

Pulp — Determination of cellulose nanocrystal sulfur and sulfate half-ester content

This document specifies procedures for the laboratory determination of the total elemental sulfur and the sulfate half-ester content of cellulose nanocrystals (CNCs) by inductively coupled plasma-optical emission spectroscopy and conductometric titration, respectively, including sample preparation, measurement methods and data analysis. This document is applicable to the characterization of CNCs: a) with all monovalent counterions (particularly hydronium and sodium cations); b) which are either in the never-dried state in aqueous suspension, or have been redispersed from a dried form; and c) which have been extracted from any naturally occurring cellulose source using a range of sulfuric acid hydrolysis conditions, or have been sulfated post-hydrolysis using sulfuric acid.

Pâte — Détermination de la teneur en soufre et en demi-ester de sulfate des nanocristaux de cellulose

General Information

• Status: Published
• Publication Date: 17-Dec-2018
• ICS: 85.040 - Pulps
• Technical Committee: ISO/TC 6 - Paper, board and pulps
• Drafting Committee: ISO/TC 6/WG 4 - Chemical analysis
• Current Stage: 9060 - Close of review
• Start Date: 04-Jun-2029

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21400
First edition
2018-12
Pulp — Determination of cellulose
nanocrystal sulfur and sulfate half-
ester content
Pâte — Détermination de la teneur en soufre et en demi-ester de
sulfate des nanocristaux de cellulose
Reference number
ISO 21400:2018(E)
©
ISO 2018

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ISO 21400:2018(E)

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ii © ISO 2018 – All rights reserved

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ISO 21400:2018(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Total elemental sulfur content — ICP-OES method . 4
5.1 Principle . 4
5.2 Reagents and apparatus . 5
5.3 Sample purification by dialysis . 6
5.4 Microwave-assisted sample digestion and sample preparation . 8
5.5 Preparation of calibration solutions and blanks .10
5.6 Analysis of standards and samples by ICP-OES .11
5.7 Calculation of dry CNC total elemental sulfur content and CNC surface charge .12
5.8 Test report .13
6 Sulfate half-ester content — Conductometric titration method .13
6.1 Principle .13
6.2 Reagents and apparatus .14
6.3 Sample purification by dialysis .15
6.4 Sample protonation by ion exchange .16
6.5 Sample analysis by conductometric titration .
...