Overview - ISO 24087:2023 (DSC for vulcanized rubber)
ISO 24087:2023 specifies a standardized method for thermal analysis of vulcanized rubber using differential scanning calorimetry (DSC). The method covers observation and measurement of physical transitions such as the glass transition temperature (Tg), melting and crystallization transitions, polymorphic transitions, and associated enthalpy changes. The standard complements general DSC principles and rubber conditioning procedures referenced in ISO 11357-1 and ISO 23529.
Key topics and technical requirements
- Scope and principle: Measures the heat-flow difference between a specimen and reference as a function of temperature/time under a controlled atmosphere. Supports both heat-flux DSC and power-compensation DSC.
- Definitions: Clear definitions for Tg, melting, crystallization, enthalpy of fusion/crystallization, and DSC baseline/temperature conventions.
- Apparatus specifications:
- Heating/cooling rates: 0.5 K/min to 50 K/min.
- Temperature resolution: 0.1 °C; accuracy ±0.5 °C or better.
- Minimum test portion mass: 1 mg (or smaller if required).
- Purge gas flow control: capability specified (controllable within 10 ml/min and 100 ml/min).
- Crucibles: same type/material, similar masses (±0.5 mg); inert under test conditions; lids or hermetic sealing as required.
- Balance: resolution 0.01 mg, accuracy ±0.1 mg or better.
- Calibration:
- Energy and temperature calibration per manufacturer instructions.
- Minimum temperature calibration using indium and another material spanning the test range; transition temperatures defined at extrapolated onset (Tei).
- Factors affecting calibration (crucible type, purge gas, sample mass, heating rates) must be controlled.
- Procedure elements:
- Baseline determination, specimen preparation and conditioning, performing measurements, Tg determination (using point of inflection), and calculation/reporting of transition temperatures and enthalpies.
- Documentation: Includes precision data, reporting requirements, and informative annexes (recommended calibration materials and precision).
Applications and users
ISO 24087 is used by:
- Rubber R&D and formulation laboratories for material characterization.
- Quality control in tire, automotive, seal, hose and conveyor-belt manufacturing.
- Materials scientists assessing glass transition temperature, crystallinity, and thermal stability of vulcanized elastomers.
- Accreditation and testing laboratories preparing DSC-based test reports for specifications and regulatory compliance.
Practical benefits include consistent Tg and enthalpy measurements, improved comparability between labs, and informed material selection and process control.
Related standards
- ISO 11357-1 - Plastics - Differential scanning calorimetry (general principles)
- ISO 23529 - Rubber - General procedures for preparing and conditioning test pieces
Keywords: ISO 24087, differential scanning calorimetry, DSC, glass transition temperature, Tg, vulcanized rubber, enthalpy, thermal analysis, calibration, crucibles, heat-flux DSC, power-compensation DSC.
Open preview (PDF)Rubber, vulcanized — Determination of the glass transition temperature and enthalpy by differential scanning calorimetry
