van gurp-palmen plots for blends of linear and branched polyethylenes at various temperatures

He rheological properties through van gurp-palmen plots have been studied for blends of linear and branched polyethylenes. the thermorheology was performed at a broad range of temperature between 130 to 280 oc by which, the change in the morphology and viscoelastic behavior can be precisely investigated. for hdpe, δ is nearly 80o at the region of low |g*|. but, ldpe showed a well-defined flat plateau near 90o at low values of |g*| meaning that the sample response is almost entirely viscous. then, at the region of high |g*| the δ drops, steeply to points which the melt is dominated by elastic response. the plot for each hdpe/ldpe blend at different temperatures coincides, and no failure of superposition was observed. these measurements confirmed there is no phase separation in the blends in the wide range of temperature. moreover, the behavior revealed that the blends are thermorheologically simple fluids and no complexity was observed.