Abstract: dynamic rheological behaviour of high density polyethylene/nano-silica composites were investigated in this paper. And discuss the surface-modification of nano-SiO₂ affect the rheological behaviour of composites. Experimental results show that PE-HD/SiO₂ composites belong to pseudoplastic fluid. The complex viscosity (η*) of the composites increased with increasing of SiO₂ content.When the content of SiO₂ is greater than 6%,η* appear increasing suddenly, and appear shear thinning behaviors. In the relation curve of the storage moduli (G′), loss moduli (G″) and frequency(ω), it is appear second flat which indicate that it is form local order percolation network because the particle is correlation and glomeration. And the surface-modification SiO₂ is not change the pseudoplastic fluid.The η* of surface-modification SiO₂ by the coupling agent system is lower. In the relation curve of the storage moduli (G′), loss moduli (G″) and frequency(ω), it is not appear second flat. The system of composites is disperse more homogeneously.

Key words: polyethylene, nano-SiO₂, percolation threshold, dynamic rheological behavior