Overview
ISO 16014-4:2019 - Plastics: Determination of average molecular weight and molecular weight distribution of polymers using size-exclusion chromatography (SEC) - Part 4: High-temperature method specifies a relative SEC method using organic eluents at elevated temperatures (60 °C to 220 °C). The standard defines how to determine average molecular weight and molecular weight distribution from a calibration curve prepared with polymer standards, and it is intended for polymers that require high-temperature dissolution and elution.
Keywords: ISO 16014-4:2019, size-exclusion chromatography, SEC, high-temperature method, molecular weight distribution, average molecular weight, polymers
Key topics and technical requirements
- Scope & principle: Relative SEC method; results calculated from a calibration curve using molecular weight standards (see ISO 16014-1 for general principles).
- Operating temperature: Column and detector operation between 60 °C and 220 °C; column temperature-control within ±0.5 K, injector within ±1 K.
- System performance:
- Pump flow-rate stability to ±0.3%.
- Column set requirements: theoretical plate number > 12 000/m, resolution factor R > 1.5, asymmetry factor 1.00 ± 0.15.
- Automatic injection required (manual injection impractical at high T).
- Reagents & additives: Organic eluents suitable for high temperatures (examples in Annex B); antioxidants such as 2,6‑di‑tert‑butyl‑4‑methylphenol to prevent degradation; recommended filtration to protect columns.
- Calibration & standards: Use narrow-distribution molecular weight standards covering the target range; alternative polymers may be used with universal calibration methods (see ISO 16014-2).
- Data handling: Chromatographic data acquisition, calibration-curve fitting and calculation of average molecular weights and distribution parameters as specified.
Applications and who uses it
- Industries: Polymer manufacturers, plastics processors, quality control laboratories, materials testing labs, and R&D facilities dealing with high‑melting or solvent‑sensitive polymers (e.g., high‑density polyethylene, engineering thermoplastics).
- Use cases:
- Accurate determination of molecular weight distribution for product specification and batch-to-batch control.
- Polymer research and development where thermal dissolution and high-temperature SEC are necessary.
- Failure analysis and characterization when conventional room-temperature SEC cannot dissolve samples.
Related standards
This standard is essential for laboratories performing high‑temperature SEC to ensure reliable, reproducible molecular weight and molecular weight distribution measurements for thermally demanding polymer systems.