BS ISO 6721-10:2015

This part of ISO6721 specifies the general principles of a method for determining the dynamic rheological properties of polymer melts at angular frequencies typically in the range of 0,01rad·s -1 to 100rad·s -1 by means of an oscillatory rheometer with a parallel-plate geometry. Angular frequencies outside this range can also be used (see Note1). The method is used to determine values of the following dynamic rheological properties: complex shear viscosity η*, dynamic shear viscosity η’, the out-of-phase component of the complex shear viscosity η”, 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 ~10MPa·s (see Note2). NOTE1 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 0,1rad·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. NOTE2 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, correction can be made for compliance effects.