Model‐Filled polymers. III: Rheological behavior of polystyrene containing cross‐linked polystyrene beads

The steady shear viscosity and dynamic moduli, at 180 and 200°C, of polystyrene composites, containing cross‐linked monodisperse polystyrene beads varying in diameter from 0.2 to 0.8 μm, are independent of bead size and cross‐link density, but increase with the volume fraction of beads. Steady shear viscosities exhibit power‐law regions up to 40% concentration of beads, but no yield stress. Storage and loss moduli are initially linear with frequency, on double logarithmic plots, with limiting slopes of 1.3 and 0.9, respectively. Uncross‐linked beads and beads cross‐linked with 0.1% divinylbenzene are destroyed by thermomechanical dispersion in the melt.