AbstractSeven samples of HDPE containing 0, 2, 5, 10, 25, 40 and 60 weight percent of mica were prepared on a roll mill at 200°C. The samples were tested atT= 150, 170, 190 and 210°C for a wide range of rate of deformation from 10−2to 2 × 104s−1. Both capillary and rotational rheometers were used. The samples were found to be thermally stable. The results indicate that η,G′, andG″ increase with mica content for the whole range of deformation rates. The relaxation time spectrum for the sample containing 60 weight percent of mica showed a particulate contribution. The zero shear viscosity was discussed in terms of suspensi