Applied Rheology (Jun 2011)
Effect of Spherical Iron Silicon (Fesi) Microparticles on the Viscosity Behaviour of Polypropylene Melt
Abstract
In this study the steady flow viscosity, complex viscosity and relative viscosity of PP/FeSi composite melts with filler contents up to x =0.7 (70 vol.%) of spherical Iron Silicon (FeSi) microparticles (in 10 vol.% steps) with diameter of d < 106 mm have been investigated. Plate-plate and capillary rheometry at different shear rate and angular frequency in the range from 0.12 to 16000 s-1 (rad/s) were used. The results show an inflection point at high filler contents x ≥ 0.4 (40 vol.%) and low shear rates (< 1 s-1) caused by particle/particle interactions. With increasing shear rate and angular frequency the typical shear thinning flow behaviour of polymer melts was found for all investigated filler contents. The viscosity increases with increasing filler content at constant shear rate and angular frequency. Time-temperature-superposition (TTS) and Cox-Merz relation were fulfilled at filler contents up to x =0.3 (30 vol.%). The results of complex viscosity were normalized to a superimposed master curve. The three parameter of the new modified Carreau model were calculated for PP melt and shifted by two factors depending on the filler content. Based on these modifications, the complex viscosity was calculated for each filler content up to x = 0.3. The complex viscosity graphs were reduced to a general master curve of the investigated PP/FeSi composites up to x = 0.3. Finally, the relative viscosity of the examined composites shows the best fit to the Quemada model.
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