Mechanical
Rheological
Heat resistance
Thermal analysis
Thermo-mechanical analysis (TMA)
Differential scanning calorimetry (DSC)
Thermogravimetric analysis (TGA)
Torsion pendulum test
Physical
Electrical
Combustion (Fire)
Thermal aging
Weathering
Optical
Chemical resistance
Shrinkage
Torsion pendulum test
Torsion pendulum test

Shear mudulus curves
Shear modulus curves

Standards:
ISO 6721-2 / -7
DIN 53445
or corresponding standards

Torsion pendulum test (determination of shear modulus)
Torsion pendulum tests are used to determine the dynamic and mechanical properties of plastics in the solid state.
A distinction is made between two basic methods:
  • Torsion pendulum method (ISO 6721-2)
  • Torsional vibration - Non-resonance method (ISO 6721-7)
In both cases a plastic sample is subjected to a shear deformation (deflection) at constant frequency and the material response detected at periodic intervals.
This gives the storage modulus G’ (shear modulus) as well as the loss modulus G’’ and the loss factor tan d.

The storage modulus is generally determined as a function of temperature.
The storage modulus curve as a function of temperature is characteristic for each plastic.

This curve can be used to identify various different states of aggregation and softening ranges, glass transition temperatures, crystalline melting points and secondary relaxation ranges.
Knowledge of the beginning of softening ranges is very important with regard to the subsequent use of a part.

Result of the test method:

Representation of the shear modulus curves of an amorphous and semi-crystalline thermoplastic determined using the torsion pendulum test. The various different states of aggregation are also identified

Test specimen:
Flat test specimen 80 x 10 x 4 or 80 x 10 x 1.