ISO 16014-4:2019

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

• ISO 16014-1 - General principles for SEC of polymers.
• ISO 16014-2 - Universal calibration method.
• ISO 472, ISO 5725-1, ISO 5725-2 - Terminology and measurement precision guidance referenced by ISO 16014-4:2019.

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.