On the Effect of Pressure on the Shear and Elongational Viscosities of Polymer Melts

Journal article, 2004

The effect of pressure and temperature on the shear and elongational deformation rate-dependent viscosities has been experimentally investigated for several polymers (HDPE, LDPE, LLDPE, PP, PC, PMMA, and PS) on a capillary rheometer with a back-pressure device. Pressure, β, and temperature, α, coefficients have been determined through simultaneous fitting of the shear and extensional viscosity data by the modified White-Metzner model. The dependence of β and α on temperature and pressure, respectively, was investigated and it has been found that simple relationships exist between pressure and temperature sensitivity coefficients for individual polymers. © 2004 Society of Plastics Engineers.