Abstract: The rhcological behavior of linear low-density polyethylene (PE-LLD)/ethylene-silsesquiox-anc(E-POSS)blend was investigated using a capillary rhcometer. Influences of composition of the blends, shear rate and shear stress on melt apparent viscosity were discussed. ion-Newtonian index(n)，swell ratio, conventional yield stress, breaking strength，and breaking extensibility of the blends at different contents of E-POSS were measured.It showed that the PE-LLD/E-POSS blends were pscu-doplastic. When the content of E-POSS was lower than 3%and the temperature was below 160℃，the melt viscosity was lower than that of neat PE-LLD; while the viscosity was higher when the content and temperature became higher. The blends exhibited maximum mechanical properties when the mass frac-tion of E-POSS was 3%.

Key words: ethylene-silsesquioxane, linear low-density polyethylene, rhcological behavior, mechanical property