Abstract: Melt rheological behaviors of the polypropylene/linear bimodal polyethylene( PP/PE-LB) blend were studied with capillary rheometer.Influences of composition, shear stress, and shearing rate on the melt rheological behavior were discussed. Non-Newtonian index( n) and melt flow activation en ergy of the melt were measured and the results showed that PP/PE-LB blends were pseudoplastic fluids.Melt viscosity of the blends increased with increasing PE-LB content. DSC and SEM showed that addi tion of PE-LB helped PP crystallize at higher temperatures. The addition of LBPE obviously increased the mechanical properties of PP. While the additions were 20 wt % and 40 wt %, the notched impact strength increased about 67% and 320%, respectively,  however, at the cost of the tensile strength lowered by 7 % and 35 %, respectively.

Key words: polypropylene;linear bimodal polyethylene, blending;rheological behavior, mechanical property