The effects of brominated flame retardant and carbon black-filling on the extrusion distortion of PP melt and dynamic rheological properties were investigated by capillary rheometer and rotational rheometer. It was shown that the more filled resin exhibited higher critical shear rate for extrusion distortion corresponding to wider processing window in low filler content range. In dynamic rheometry

the higher filled resins behavior in shear thinning with higher complex viscosity

storage modulus and loss modulus instead of lower loss factor. Quantitative analyses were conducted using entanglement model and Cross model. Filler can absorb polymer chains to reduce wall adsorption dropping distortion and result in higher critical shear rate. Particle filled network increases in the plateau modulus and entanglement density shortening relaxation time for quicker recovering according to smaller extrusion swell ratio. Carbon black more than 3.5%(mass) in composite forms percolation network being characterized by higher zero shear viscosity and longer relaxation time where liquid-solid-like transition occurs. Simultaneously

the surface resistivity decreased obviously. The viscoelastic percolation value consistent with the electrical percolation value approximately.