ISO 13885-1:2020

Overview

ISO 13885-1:2020 specifies a standardized procedure for determining the molar-mass distribution and average molar masses Mn (number average) and Mw (weight average) of polymers soluble in tetrahydrofuran (THF) using gel permeation chromatography (GPC), also known as size exclusion chromatography (SEC). The document covers principle, apparatus, reagents, calibration, data acquisition and evaluation, and reporting requirements for THF-based GPC systems used in polymer characterization.

Key topics and technical requirements

• Scope & limitations
  • Applicable to polymers soluble in THF; not applicable to samples with Mw > 1×10^6 g·mol⁻1 or with elution outside the calibration range.
  • Method can fail for polymers that interact with the system (e.g., adsorption); no correction methods for peak broadening are included.
  • For absolute molar-mass values, alternative methods (e.g., membrane osmometry for Mn, light scattering for Mw) are recommended.
• Principle
  • Separation based on molecular coil size: large molecules elute earlier; small molecules penetrate pores and elute later.
• Apparatus & operational parameters
  • Eluent: THF must be degassed (bubble trap, helium purge, or vacuum degassing are acceptable) and protected from atmosphere/light.
  • Pump: smooth, pulse-free flow; recommended 1 mL/min (flow stability ≤ 0.1%).
  • Injection: loops or autosamplers; sample concentration typically < 5 g·L⁻1.
  • Columns: series-packed porous (spherical) media; column temperature control is required.
  • Detectors: concentration-sensitive detectors (typically a differential refractometer) are used.
• Calibration & data handling
  • Use appropriate polymer calibration standards and plot the calibration curve within the defined elution range; baseline determination, net chromatogram correction, and calculation of distribution curves and Mn, Mw are specified.
• Safety
  • THF is hazardous; users must observe appropriate laboratory safety and regulatory requirements.

Practical applications and users

• Routine polymer characterization in quality control and R&D: molecular-weight profiling, batch-to-batch comparison, formulation development.
• Industries: paints and varnishes, plastics, adhesives, coatings, polymer manufacturing, academic polymer science labs, and contract testing laboratories.
• Useful for teams performing GPC analysis, method validation, instrument qualification, and inter-laboratory comparisons where THF is the solvent of choice.

Related standards

• ISO 13885 series (other parts cover different eluents/methods)
• ISO 1513 - Examination and preparation of test samples
• ISO 4618 - Paints and varnishes - Terms and definitions
• ISO 15528 - Sampling for paints, varnishes and raw materials

Keywords: ISO 13885-1, gel permeation chromatography, GPC, size exclusion chromatography, THF eluent, Mn, Mw, molar-mass distribution, polymer characterization, GPC calibration.