Overview
ISO/TR 19716:2016 - Nanotechnologies - Characterization of cellulose nanocrystals (CNCs) is a Technical Report from ISO/TC 229 that reviews commonly used methods for CNC characterization. The report summarizes best practices for sample preparation, measurement methods and data analysis/interpretation for key measurands relevant to commercial production and application of cellulose nanocrystals. It covers CNC composition, morphology and surface characteristics but does not prescribe specific standard test methods or address post-production modifications or CNC-containing products.
Key Topics
The Technical Report provides a structured review of measurement approaches and analytical considerations for CNCs, including:
- Sample preparation and data analysis: guidance on preparing CNC suspensions and interpreting measurement results for reproducible reporting.
- Composition and chemistry:
- Chemical composition and surface functional groups (e.g., determination of sulfate half‑esters and carboxylic acids).
- Degree of polymerization, crystallinity (CrI) assessment and moisture content.
- Detection of contaminants and residual biomass-derived impurities (including metal ions).
- Analytical techniques discussed: XRD (X‑ray diffraction), ssNMR (solid‑state NMR), FTIR, ICP‑MS/OES, and titration/ion‑exchange methods.
- Morphology and sizing:
- Microscopy: TEM, SEM/FE‑SEM and AFM for length and cross‑section distributions and image analysis considerations.
- Light‑scattering: dynamic light scattering (DLS) for hydrodynamic diameter and polydispersity.
- Surface characteristics:
- Specific surface area (BET) and surface charge (electrophoretic mobility, zeta potential).
- Surface composition techniques such as XPS (X‑ray photoelectron spectroscopy).
- Miscellaneous properties:
- Thermal properties (TGA, DSC) and rheological behaviour (viscosity) relevant to processing and end‑use.
Applications
ISO/TR 19716:2016 is useful for stakeholders working with cellulose nanocrystals, including:
- Researchers and R&D teams developing CNC synthesis, characterization protocols and new CNC‑based materials.
- Manufacturers and quality control laboratories aiming to characterize production batches and ensure consistent material quality.
- Standards developers and regulatory bodies seeking an overview of measurement issues and candidate measurands for future normative standards.
- Product formulators (composites, coatings, rheology modifiers, biomedical materials, optical films) who need to understand how CNC properties influence performance.
Related Standards
- The report references ISO/TS 80004‑2 (nanotechnology - vocabulary/terminology) and notes ongoing ISO/TC 229 work on cellulose nanomaterial terminology. It also cites the existence of national guidance (e.g., CSA Z5100) and CNC reference materials released in earlier years.
Keywords: ISO/TR 19716:2016, cellulose nanocrystals, CNC characterization, nanotechnologies, crystallinity, TEM, AFM, DLS, surface charge, BET, XRD.