Overview
EN ISO 1628-1:2024 (ISO 1628-1:2024) defines the general principles for measuring the viscosity of organic polymers in dilute solution using capillary viscometers. The standard specifies the conditions and standard parameters for determining reduced viscosity, intrinsic viscosity and K‑value. It applies both when developing polymer-specific viscosity standards and when no separate standard exists for a given polymer. This edition supersedes EN ISO 1628-1:2021 and adds an alternative differential pressure method alongside the established efflux time method.
Key topics and requirements
- Measurement principles: Two equivalent approaches are described - the efflux time method and the differential pressure method - with guidance on their implementation and comparability.
- Apparatus: Requirements for capillary viscometers and related equipment are defined for both methods (efflux time and differential pressure).
- Solution preparation: General rules for solvent selection, sample preparation and recommended concentration ranges for dilute solutions.
- Temperature control: Procedures and requirements for maintaining and reporting measurement temperature.
- Procedure and data collection: Stepwise guidance on charging viscometers, measuring flow or pressure signals, and capturing raw data.
- Expression of results: Calculation and reporting instructions for reduced viscosity, intrinsic viscosity and K‑value.
- Quality and error control: Informative annexes on sources of error, cleaning of apparatus and good laboratory practice.
- Normative references: Includes cross-references to ISO 80000-1 and ISO 80000-4 for quantities and units.
Practical applications
- Quality control and batch verification of polymer resins and solutions.
- Estimation of polymer molecular characteristics (via intrinsic viscosity correlations) and formulation control for coatings, adhesives and processing fluids.
- R&D and materials characterization workflows where solution viscosity is used to compare polymer grades or monitor synthesis/purification.
- Integration into automated laboratory workflows - the differential pressure method is highlighted for easier automation, reduced solvent use and higher throughput.
Who should use this standard
- Polymer testing laboratories and QA/QC teams in plastics and chemical industries.
- R&D scientists working on polymer synthesis, formulation and characterization.
- Manufacturers of viscometers and laboratory automation systems.
- Standards developers and regulatory bodies needing harmonized reporting of polymer solution viscosity.
Related standards
- Other parts of the ISO 1628 series (for polymer-specific viscosity methods) - see the ISO website for the complete list.
- ISO 80000-1 and ISO 80000-4 (quantities and units) are normative references used in this document.
Keywords: EN ISO 1628-1:2024, ISO 1628-1, viscosity of polymers, capillary viscometers, intrinsic viscosity, reduced viscosity, K‑value, efflux time method, differential pressure method, polymer solution viscosity measurement.
