Melt rheological properties of polypropylene–wood flour composites

This article presents study of melt rheological properties of composites of polypropylene ( i ‐PP) filled with wood flour (WF), at filler concentrations of 3–20 wt%. Results illustrate the effects of (i) filler concentration and (ii) shear stress or shear rates on melt viscosity and melt elasticity properties of the composites. Incorporation of WF into i ‐PP results in an increase of its melt viscosity and a decrease of melt elasticity such as die swell and first normal stress differences; these properties, however, depend on filler concentration. Processing temperature of the filled i ‐PP increases as compared to the nonfilled polymer.