Overview
EN ISO 307:2019 - Plastics - Polyamides - Determination of viscosity number (ISO 307:2019) specifies a standardized laboratory method to determine the viscosity number of dilute solutions of polyamides. The procedure follows the general approach of ISO 1628‑1, with polyamide‑specific solvents, apparatus and conditions. The standard applies to a wide range of polyamides (PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA MXD6 and various copolyamides and blends defined in ISO 16396‑1), except polyamides produced by anionic polymerization or cross‑linked materials that are normally insoluble in the specified solvents.
Key topics and requirements
- Scope of applicability: Lists the polyamide types and notes exclusions (anionic polymerization and cross‑linked polyamides).
- Principle and procedure: Viscosity number determination for dilute polymer solutions using capillary viscometers in accordance with ISO 1628‑1, with polyamide‑specific conditions.
- Solvent selection and control: Specifies the permitted solvents and stresses correct solvent concentration (annexes cover adjustment of commercial sulfuric acid to 96 % and formic acid to 90 %), temperature control and potential use of the Hagenbach correction.
- Apparatus: Recommends two specific viscometer types; other viscometers from ISO 3105 may be used if equivalency is demonstrated.
- Sample preparation: Requirements for preparing test samples, handling additives, and separation of insoluble fillers (e.g., fibres).
- Calculation and reporting: Methods for calculating test portions, expressing the viscosity number, and required test report items.
- Performance characteristics: Information on repeatability and reproducibility, and on solvent‑to‑solvent relationships (conversion caveats).
Practical applications and users
- Quality control and production monitoring: Manufacturers use EN ISO 307:2019 for routine batch control and to track polymer molecular‑weight–related properties (viscosity number).
- Incoming inspection and supplier comparison: Material specifiers and purchasing teams verify polyamide batches against supplier data.
- R&D and formulation: Researchers evaluate effects of polymerization, processing and additives on viscosity behavior.
- Failure analysis and material selection: Engineers use viscosity number results to support material selection and troubleshooting.
Note: Results are solvent‑dependent - additives can change measured values, so the method is most reliable for intra‑product comparison or for pure polyamides where solvent conversions are established.
Related standards
- ISO 1628‑1 (viscosity of polymers in dilute solution - general procedure)
- ISO 16396‑1 (polyamide designation)
- ISO 3105 (capillary viscometers)
- ISO 1042 (volumetric flasks and laboratory glassware)
Keywords: EN ISO 307:2019, viscosity number, polyamides, polyamide viscosity, capillary viscometer, solvent selection, polymer quality control.