Overview
ISO/TS 11308:2020 - Nanotechnologies: Characterization of carbon nanotube samples using thermogravimetric analysis (TGA) - provides practical guidelines for using TGA to analyze samples that contain carbon nanotubes (CNTs). The technical specification covers testing in inert or oxidizing atmospheres to assess purity, non‑carbon impurities (for example, metal catalyst residues), and to give qualitative information on thermal stability and homogeneity of CNT-containing materials. It also emphasizes that TGA is complementary to other characterization methods when identifying specific CNT types or metallic compositions.
Key Topics and Requirements
- Measurement principles: TGA measures mass change versus temperature/time; interpretation uses both mass loss curves and derivative thermogravimetric (DTG) peaks (e.g., primary oxidation temperature).
- Test atmospheres: Guidance for performing TGA in oxidizing or inert environments to probe different reaction kinetics.
- Purity assessment: Quantitative determination of non‑volatile residues (commonly metal catalyst particles) via residual mass after heating; TGA alone cannot fully resolve all carbonaceous species.
- Thermal stability & homogeneity: Qualitative evaluation using oxidation temperatures and decomposition profiles.
- Sampling and sample handling: Recommendations on sample pan selection (aluminium, ceramic, platinum options), sample size, and avoidance of compaction to ensure representative results.
- Data interpretation: Identification of constituents via oxidation peaks, consideration of exothermic combustion events (possible catalytic burning), and reporting of uncertainties.
- Instrument coupling: TGA can be coupled with techniques (e.g., MS, GC, FTIR) to identify evolved gases and improve analytical specificity.
- Reporting: Required elements for a test report, including conditions, residual mass, oxidation temperatures and uncertainty estimates.
Applications and Users
Who uses ISO/TS 11308:2020?
- Analytical and materials testing laboratories performing CNT characterization
- CNT manufacturers and suppliers for quality control and purity verification
- R&D teams developing CNT materials and composites
- Regulatory bodies and standardization groups assessing material safety and compliance
Practical uses:
- Quantifying metal catalyst residues and other non‑volatile impurities
- Comparing thermal stability across CNT batches or after processing/purification
- Screening for sample homogeneity prior to more specific analyses
- Providing standardized TGA data for supply chains and material datasheets
Related Standards
- Normative reference: ISO/TS 80004-3 (Nanotechnologies - Vocabulary - Part 3: Carbon nano-objects)
- ISO/TS 11308:2020 is intended to be used alongside complementary characterization techniques (microscopy, spectroscopy, elemental analysis) to build a full compositional profile.
Keywords: ISO/TS 11308:2020, thermogravimetric analysis, TGA, carbon nanotube, CNT characterization, purity assessment, thermal stability, homogeneity, nanotechnologies.