Overview
ISO 180:2023 - "Plastics - Determination of Izod impact strength" specifies a standardized laboratory method to measure the Izod impact strength of plastics under defined conditions. The fifth edition (2023) defines specimen types and notches, test configurations and parameters for different classes of plastics (thermoplastics, thermosets, fibre‑reinforced composites and thermotropic liquid‑crystal polymers). The test breaks a specimen mounted as a vertical cantilever beam by a single pendulum impact; results are reported as absorbed energy per original cross‑sectional area (kJ/m²) to estimate brittleness or toughness within the method’s limitations.
Key topics and technical requirements
- Test principle: cantilever (Izod) configuration with a pendulum striker; impact location and clamp position are defined.
- Specimens: dimensions, notch types and preparation methods are specified for moulded, extruded, sheet and some composite materials. Notched and unnotched results are treated separately.
- Apparatus & verification: requirements for impact‑testing machines and verification are referenced to ISO 13802; control of clamping force is emphasized for clamping‑sensitive plastics.
- Measurement accuracy: micrometers and gauges must measure specimen dimensions to an accuracy of 0.02 mm; for notched specimens the micrometer anvil width shall be 2–3 mm to suit the notch profile.
- Conditioning and preparation: specimen conditioning atmospheres and moulding/injection/ machining preparation follow referenced standards (ISO 291, ISO 293, ISO 294‑1, ISO 295, ISO 2818, ISO 10724‑1, ISO 20753).
- Calculation and reporting: formulas yield Izod impact strength for notched and unnotched specimens; statistical treatment, significant figures and precision (including results of an interlaboratory study for unnotched specimens in Annex A) are included.
- Limitations: ISO 180 is not generally suitable for rigid cellular materials, sandwich structures, and typically not for notched long‑fibre composites or thermotropic liquid‑crystal polymers.
Practical applications and users
ISO 180:2023 is used for:
- Quality control and batch verification of plastic compounds and sheets
- Material selection and comparison in product development and R&D
- Failure analysis and assessment of toughness or brittleness changes due to formulation or processing
- Testing of fibre‑reinforced composites (with some restrictions)
Typical users:
- Material and polymer testing laboratories
- Plastics and composite manufacturers
- Product designers and engineers evaluating impact performance
- Certification and compliance bodies
Related standards
Keywords: ISO 180:2023, Izod impact strength, plastics impact testing, notched specimens, unnotched specimens, pendulum impact, polymer toughness, impact test standard.