Some correlations involving the shear viscosity of polystyrene melts

Based upon a compilation of steady-shear and dynamic-shear viscosity data from the literature for polystyrene melts, an assessment has been made concerning the relative merits of the Cross and Carreau models in describing the shear-rate dependence of such viscosities. It is shown that the Cross model is decidedly more appropriate for PS of BMWD. Based upon master plots, it is demonstrated that the Cox-Merz relation applies to PS of both BMWD and NMWD. It is also shown that the Cox-Merz relation applies even into the second-Newtonian regime, with being independent ofM_w and MWD. In addition, the applicability of the Prest-Porter-O'Reilly relationship between shear viscosity and recoverable shear compliance is corroborated in the case of PS of NMWD.