What is ISO 6721-10 - Complex shear viscosity of plastics using a parallel-plate oscillatory rheometer about?
Plastics are globally popular because they are durable, flexible, lightweight and can be shaped into any form.
ISO 6721-10 specifies the general principles of a method for determining the dynamic rheological properties of polymer melts at angular frequencies typically in the range of 0,01 rad·s-1 to 100 rad·s-1 by means of an oscillatory rheometer with a parallel-plate geometry. Angular frequencies outside this range can also be used. The method is used to determine values of the following dynamic rheological properties: complex shear viscosity, dynamic shear viscosity, the out-of-phase component of the complex shear viscosity, complex shear modulus G*, shear loss modulus G”, and shear storage modulus G’. It is suitable for measuring complex shear viscosity values typically up to ~10 MPa·s.
Note 1: The angular-frequency measurement range is limited by the specification of the measuring instrument and also by the response of the specimen. When testing using angular frequencies lower than 0,1 rad·s–1, the test time can increase significantly as the time taken to obtain a single measurement is proportional to the reciprocal of the angular frequency. Consequently, when testing at low angular frequencies, degradation or polymerization of the specimen is more likely to occur and have an effect on the results. At high angular frequencies, the specimen can distort or fracture at the edge, consequently invalidating the test results.
Note 2: The range of complex shear viscosity values that can be measured is dependent on the specimen dimensions and also the specification of the measuring instrument. For a specimen of given dimensions, the upper limit of the range is limited by the machine’s torque capacity, angular-displacement resolution, and compliance. However, corrections can be made for compliance effects.
Who is ISO 6721-10 - Complex shear viscosity of plastics using a parallel-plate oscillatory rheometer for?
ISO 6721-10 on complex shear viscosity of plastics using a parallel-plate oscillatory rheometer is useful for organizations associated with:
- Manufacturers and designers of plastics products
- Engineering-design team
- Research and development team
- Quality control teams
Why should you use ISO 6721-10 - Complex shear viscosity of plastics using a parallel-plate oscillatory rheometer?
The main ingredient of plastics is polymers. Plastic's resistance for polymer flowing during the profile extrusion operation is called the shear viscosity.
ISO 6721-10 walks you through a test method of determining the complex shear viscosity of plastics using a parallel-plate oscillatory rheometer. This includes:
- Temperature measurement and control
- Test temperature
- Zeroing the gap
- Determination of thermal stability of sample material
- Determination of region of linear-viscoelastic behaviour
- Frequency sweep
- Temperature sweep
- Air entrapment
- Calculation of complex shear modulus and complex shear viscosity
The guidelines in ISO 6721-10 help you determine dynamic mechanical properties like complex shear viscosity of plastics for further industrial uses, so that end customers can use superior quality products.

