Standard Specification
International standardization protocols define rules for measuring dynamic mechanical properties of plastics under non-resonant forced vibration conditions. Achieving iso 6721 compliance requires strict adherence to specified specimen geometry and temperature sweep rates during dynamic testing. The standard governs determination of dynamic storage modulus and loss factor across specified frequency ranges.
Scope limits exclude non-rigid cellular plastics and dynamic testing under resonant conditions covered by separate standards.
Test Execution
Dynamic mechanical analyzers must maintain sinusoidal displacement control within narrow percentage tolerances throughout temperature sweeps. Temperature sensors positioned near the specimen register environmental conditions with calibrated accuracy traceable to national standards. Specimen clamping forces require adjustment to maintain contact without causing compressive deformation during thermal expansion.
Dynamic force transducers undergo static and dynamic calibration routines before test execution.
Data Reduction
Mathematical formulas convert raw force and phase angle data into complex shear or flexural moduli. System compliance correction factors subtract machine deformation from raw strain measurements. Instrument software processes raw data streams to extract dynamic moduli without manual interpolation.
Calculated loss tangent values identify material glass transition temperatures with standardized repeatability.
Laboratory Audit
Quality assurance procedures verify instrument calibration records and operator adherence to standard test parameters. Inter-laboratory round robin testing checks measurement reproducibility across different test frames and operators. Deviation from prescribed specimen dimensions introduces systematic errors into modulus calculations.
Test reports must document heating rates and exact clamping configurations to maintain certified status.
