Overview
EN ISO 11357-8:2021 - Plastics: Differential scanning calorimetry (DSC) - Part 8: Determination of thermal conductivity (ISO 11357-8:2021) defines a DSC-based method to determine the thermal conductivity of solid plastics and composites (unfilled, filled or fibre‑reinforced) with conductivities up to 1 W/(m·K). Published by CEN/ISO in 2021, the standard adapts a DSC measurement configuration to quantify heat flow through a specimen using a known melting substance placed on top of the sample.
Key topics and technical requirements
- Scope and applicability: Solid plastics and polymer composites; upper limit ~1 W/(m·K).
- Measurement principle: Specimen is placed on the DSC sample sensor, with an empty reference crucible in the reference position and a crucible containing a substance of known melting point (e.g., gallium) on top of the specimen. The slope of the melting peak and the differential heat flow between sample and reference are used, together with specimen thickness and temperature difference, to calculate thermal conductivity.
- Apparatus & materials:
- DSC instrument compliant with ISO 11357‑1 (heat‑flux instruments verified; power‑compensated expected to be suitable).
- Crucibles, a melting substance with known melting temperature, protective lacquers and measurement tools for specimen height.
- Specimen requirements: Defined geometry, sampling number and conditioning per standard atmospheres.
- Calibration & data: Use original raw DSC data only; calibration procedures and evaluation of melting-peak slopes are specified.
- Support information: Sections on calculation methodology, crucible service life (when using gallium), precision and bias, and an informative annex describing an interlaboratory study.
Applications and users
- Who uses it: Materials testing laboratories, plastics manufacturers, composite developers, R&D labs, quality and certification bodies requiring standardized thermal-property data.
- Practical value:
- Enables concurrent measurement of specific heat capacity using the same DSC instrument; combined with density and thermal conductivity, users can calculate thermal diffusivity (thermal conductivity ÷ (density × specific heat capacity)).
- Cost‑effective solution for labs that already possess DSC equipment - avoids procurement of separate thermal conductivity instruments.
- Useful for thermal design, material selection, safety analysis and simulation inputs in electronics, automotive, building materials and composite component development.
Related standards
- ISO 11357‑1 - DSC: General principles
- ISO 291 - Standard atmospheres for conditioning and testing
- ISO 472 - Plastics vocabulary
- ISO 6344‑1 - Grain size analysis (referenced for specimen preparation)
EN ISO 11357‑8:2021 provides a standardized, DSC‑based procedure for reliable thermal‑conductivity data on plastics and composites, integrating naturally into laboratories that already perform DSC analyses.
