Experimental Studies of the Influence of Particle and Fiber Reinforcement on the Rheological Properties of Polymer Melts

Abstract

An experimental study is reported on the rheological properties of compounds of a polystyrene melt with calcium carbonate, carbon black, titanium dioxide, calcium sulfate anhydride fiber, mica, glass beads and aramid, cellulose and glass fibers. Comparison is made of the shear viscosity, elongational viscosity and principal normal stress difference of these compounds at 20 volume per cent loadings. The polymer matrix and compounds with the smallest particle dimension greater than 10µ exhibit low shear rate Newtonian viscosities. Suspensions with particle sizes 0.5µ and smaller exhibit yield values. Yield values are also observed in elongational flow for systems exhibiting yielding in shear flow. The experimental data are contrasted to both mechanistic theories of suspensions with interaction between particles and a phenomenological plastic-viscoelastic tensor constitutive equation.