ISO 6031:2025

Overview

ISO 6031:2025 - Functional extenders for special application - Nanoscale diamonds for polymer composites - specifies requirements and corresponding test methods for nanoscale diamonds (nanodiamonds) used as functional additives in polymer composites. The standard covers material classification, designation, sampling, marking and labelling, technical requirements, and the tests required to verify conformity when nanodiamond powders, suspensions or solid nanodispersions are supplied for polymer compounding.

Key topics and technical requirements

• Scope and classification
  • Materials are classified by production method (DND - detonation, LND - laser, HPHTND - high-pressure high-temperature) and by surface modification (e.g., hydroxylation, carboxylation, amination).
  • Formulations: powder, suspension, or solid nanodispersion; designation includes code, matrix and concentration (e.g., DND-W-10, HPHTND-Ep-5).
• Essential material attributes and test methods
  • Appearance (visual) - required for every lot (powder: grey to brown; suspensions: homogeneous without sedimentation).
  • Crystallinity - cubic diamond crystal structure (XRD).
  • Primary particle size - average ≤ 100 nm (TEM or XRD).
  • Chemical composition - total carbon > 80% (IEC TS 62607-4-6); sp3 (diamond) carbon > 25% (XPS).
  • Lattice parameter - 0.350 to 0.360 nm (XRD).
  • Initial oxidation temperature in air - > 440 °C (TGA) - required on every lot.
  • Ash content - ≤ 0.5% (ISO 3262-1).
  • Testing frequency: some tests are necessary for every lot (appearance, oxidation temperature), while others are typical (periodic - e.g., every six months or after production changes).
• Designation and labelling
  • Standardized naming conventions to ensure clear communication of nanodiamond type, surface functionalization and concentration in dispersions.

Practical applications

• Performance enhancement in polymer composites: improved strength, wear resistance, flexibility, thermal conductivity and stability, and radiation resistance.
• End uses: high-performance plastics, coatings, adhesives, thermal interface materials, and specialty composites in automotive, aerospace, electronics and medical sectors.
• Formulation benefits: surface-modified nanodiamonds help compatibility and dispersion in polymer matrices, reducing aggregation and enabling targeted property improvements.

Who should use ISO 6031:2025

• Nanodiamond manufacturers and suppliers (to specify product conformity and labelling)
• Polymer compounders and composite manufacturers (to select suitable functional extenders)
• Quality control and analytical labs (to apply the required test methods)
• R&D teams developing nanodiamond-enhanced polymers
• Regulators and procurement teams specifying material acceptance criteria

Related standards

Relevant normative references include ISO 9277 (BET surface area), ISO 787-9 (pH of aqueous suspensions), ISO 3262-1 (extender test methods), ISO 4618 (paints and varnishes vocabulary), and IEC/TS methods for carbon analysis and surface chemistry.