ABSTRACT
This chapter discusses the flow behavior of concentrated suspensions that may be of interest in processing composites and similar polymeric materials. Changes in the particle surface, whether they are intentional or arise out of subtle changes in the manufacturing process, have large effects on the rheology of these suspensions. There are very few published measurements available of the rheological properties of fiber suspensions in shearing flows at the concentration levels of interest in practice and only one of these contributions, Chan, White, and Oyangi employed polymeric fluids for the suspending liquids. Since the viscosity decreases more rapidly with increasing shear rate for the most highly filled systems, the relative viscosity also decreases with increasing shear rate. If viscoelastic and shear-thinning molten polymers are employed as the suspending liquid for the fiber suspension the viscosity of the suspending liquid should be evaluated at the high shear rates extant between the particles.
