Overview
ISO 4664-2:2006 specifies torsion-pendulum methods for measuring the dynamic shear properties of vulcanized and thermoplastic rubbers at low frequencies. The standard covers determination of the elastic shear modulus (in-phase modulus) and mechanical damping (loss behavior) over a wide temperature range at frequencies from 0.1 Hz to 10 Hz and at very small shear strains (≤ 5 × 10⁻⁴). It is principally intended to identify viscoelastic transitions (temperature-dependent changes in modulus and damping), rather than to provide highly accurate absolute modulus values.
Key topics and technical requirements
- Test principle: Torsion pendulum using a strip test piece clamped at both ends; the test piece forms the elastic member of the pendulum.
- Three test methods:
- Method A: Inertial member supported by the test piece (free damped oscillation).
- Method B: Inertial member supported by a fine suspension wire (free damped oscillation).
- Method C: Forced (maintained) oscillation using electromagnetic or equivalent compensation to hold constant amplitude.
- Specimen dimensions & preparation: Typical strip thickness (1.0 ± 0.2) mm; width 5–11 mm (10 mm preferred); length 40–120 mm to fit clamps. Test pieces prepared and conditioned per ISO 23529.
- Temperature control: Thermostatted chamber (gaseous medium) with control typically between −100 °C and +200 °C; maintain within ±1 °C. Measurements at maximum intervals of (10 ± 1) °C, closer in transition regions.
- Measurement accuracy & limits:
- Frequency measurement: ±1% in elastic region (±5% in transition).
- Deformation amplitude measurement: ±1%.
- Restoring torque of suspension wire ≤25% of combined restoring torque.
- Minimum of three test pieces per test; condition at standard laboratory temperature for ≥3 hours before testing.
- Strain limitation: Shear strain must not exceed 5 × 10⁻⁴ (keep torsion angles very small).
Applications
- Characterising temperature-dependent viscoelastic transitions (glass transition, damping peaks) in rubber compounds.
- R&D and formulation screening for vulcanized and thermoplastic elastomers.
- Comparative quality-control testing of rubber batches or formulations.
- Supporting material selection for vibration isolation, seals, damping components, and low-frequency dynamic applications.
Who should use this standard
- Materials testing laboratories, rubber compounders, product development teams, quality engineers, and test-equipment manufacturers needing standardized low-frequency shear measurements on rubber.
Related standards
- ISO 4664-1: Rubber - Determination of dynamic properties - Part 1: General guidance.
- ISO 23529: Rubber - General procedures for preparing and conditioning test pieces for physical test methods.
Keywords: ISO 4664-2:2006, torsion pendulum, dynamic properties, shear modulus, mechanical damping, low-frequency rubber testing, vulcanized rubber, thermoplastic rubber.
Open preview (PDF)Rubber, vulcanized or thermoplastic — Determination of dynamic properties — Part 2: Torsion pendulum methods at low frequencies
