Testing and Measuring A critical Review of the applicability of the Cox-Merz Relationship on filled Rubber Compounds

The Cox-Merz rule is one of the most important empirical rheological transfer functions with considerable practical importance in the plastics industry. In this paper, the applicability of the empirical rheological transfer function of the Cox-Merz rule to filled rubber compounds of practical relevance is investigated.

High-pressure capillary rheometers (HPCR) are widely used to characterize the flow behavior of thermoplastic melts and rubber compounds. The derivation of the viscosity relation between wall shear stress and shear rate assumes a fully developed, steady, isothermal flow of a Newtonian fluid with the boundary condition of wall adhesion.