Overview
ISO 11344:2016 specifies a standardized laboratory method for determining the molecular-mass distribution of solution polymers (raw synthetic rubber) by gel permeation chromatography (GPC), also known as size exclusion chromatography (SEC). The method applies to polymers that are completely soluble in tetrahydrofuran (THF) and covers a molecular-mass range from 5 × 10^3 to 1 × 10^6, with molecular masses reported expressed as polystyrene. ISO 11344:2016 defines practical procedures, calibration, apparatus and reporting requirements - it does not cover the theoretical background of GPC.
Key topics and technical requirements
- Scope and principle: Separation by macromolecule size on GPC columns and determination of number-average (Mn) and mass-average (Mw) molecular masses from retention times and detector response.
- Reagents and materials:
- THF (analytical grade), with or without BHT (2,6-di-tert‑butyl‑4‑methylphenol) for sample solvent and mobile phase.
- Certified polystyrene reference standards (minimum ~10 standards) covering the calibration range.
- Apparatus:
- GPC system: solvent reservoir, degasser (or helium sparging), precision pump, injector/auto-sampler, columns (packed cross‑linked polystyrene/divinylbenzene beads), detector (e.g., differential refractometer or UV), integrator/software.
- PTFE syringe filters (0.45–0.50 µm), syringes, optional auto-collector.
- Analytical conditions (typical values):
- Flow rate: 0.2–1.0 ml/min
- Injection volume: 100 µl (total injection ≤ 250 µl)
- Sample concentration: 0.1 g/l to 5.0 g/l
- Column temperature: 40–45 °C
- Calibration and procedure:
- Use polystyrene standards dissolved in THF + BHT, prepare multiple concentrations, filter, inject, then plot retention time vs log(M) and fit an appropriate polynomial. Required correlation coefficient typically very high (example: >0.9995).
- Solvent degassing and column flushing procedures to ensure baseline stability and remove peroxides.
- Results and reporting:
- Determine Mn, Mw, Mz, peak molecular mass, and polydispersity (Mw/Mn). Annexes provide software and manual calculation guidance and precision data.
Practical applications
- Quality control and acceptance testing of raw synthetic rubber and other solution polymers.
- R&D and formulation development to correlate molecular-mass distribution with material properties (viscosity, mechanical performance).
- Supplier and contract testing labs needing reproducible GPC procedures for regulatory or purchase specifications.
- Instrument validation and method transfer between laboratories.
Who should use ISO 11344:2016
- Polymer chemists, analytical scientists, and QC personnel in rubber and polymer manufacturing.
- Testing laboratories performing GPC/SEC analyses.
- Instrument manufacturers and calibration labs developing or validating GPC methods.
Related standards
- ISO 11344:2016 complements other ISO and industry standards for rubber testing and polymer characterization (consult national standards bodies for related GPC/SEC and safety standards).
Keywords: ISO 11344:2016, gel permeation chromatography, GPC, size exclusion chromatography, molecular-mass distribution, THF, polystyrene standards, raw synthetic rubber, polydispersity.
Open preview (PDF)Rubber, raw synthetic — Determination of the molecular-mass distribution of solution polymers by gel permeation chromatography
