Overview
EN ISO 11357-5:2025 - Plastics - Differential scanning calorimetry (DSC) - Part 5 defines a standardized method for using conventional DSC to determine characteristic reaction-curve temperatures and times, enthalpy of reaction, and degree of conversion for monomers, prepolymers and polymers (solid or liquid). Published and endorsed by CEN in 2025, this edition limits scope to conventional DSC (not fast DSC) and updates earlier editions to reflect current laboratory practice.
Key topics and technical requirements
- Scope and materials: Applies to monomers, prepolymers and polymers; materials may contain fillers and/or initiators in solid or liquid form. Not applicable to fast DSC (see ISO 23976).
- Methods: Two principal DSC approaches are specified:
- Temperature‑scanning method - perform a controlled scan (recommended scan rates typically 5 K/min to 20 K/min) to capture reaction peaks and determine characteristic temperatures and reaction enthalpy.
- Isothermal method - determine characteristic times and enthalpy at constant temperature; procedures include constant-temperature starts and starts from ambient temperature, plus methods to assess residual enthalpy.
- Specimen and apparatus: Follow general DSC apparatus, specimen preparation and calibration requirements as given in ISO 11357-1. Typical specimen mass: 5 mg to 20 mg, adjusted to keep thermal effects within instrument range.
- Safety and test limits: Final scan temperature must be below onset of decomposition; caution for materials that can run away or release volatiles (use gas‑tight crucibles where needed).
- Results and reporting: Procedures for calculating characteristic temperatures, times, enthalpy of reaction and degree of conversion (α) from both scanning and isothermal data are defined; precision and required test-report elements are included.
Practical applications
- Reaction profiling for polymerization and crosslinking processes.
- Quantifying curing enthalpy and conversion for thermosets, adhesives, coatings and composite resins.
- R&D for new monomers/prepolymers, formulation optimization (fillers/initiators) and process development.
- Quality control and batch release testing in polymer manufacturing and materials labs.
Who should use this standard
- Polymer scientists and materials engineers
- DSC/thermal analysis laboratory technicians
- R&D teams in plastics, adhesives and composites
- Quality assurance and regulatory groups requiring standardized thermal reaction data
Related standards
- ISO 11357-1 (General principles and calibration for DSC)
- ISO 23976 (Fast DSC - not applicable to this document)
- Other parts of the ISO 11357 series for complementary DSC test methods
Keywords: EN ISO 11357-5:2025, differential scanning calorimetry, DSC method plastics, enthalpy of reaction, degree of conversion, polymerization, crosslinking.