Melt Rheology of Two Engineering Thermoplastics: Poly(ether Imide) and Poly(2,6‐Dimethyl‐1,4‐phenylene Ether)

Material functions of two engineering plastics [a poly(phenylene ether) and a polycether imide)] were characterized, including the shear viscosity, first normal stress coeffkient, storage and loss moduli, growth and relaxation of shear stress, and first normal stress coeffkient and relaxation moduli. The oscillatory shear and relaxation moduli data were employed to determine the temperature-depen-dent parameters of Wagner model. Various material functions, which were deter-mined on the basis of this model in conjunction with the fitted parameters agreed reasonably well with the experimental results. The reported data and parameters should facilitate a better understanding of the processability charac-teristics of these two engineering plastics.