Rheological behavior of poly(methyl methacrylate) dispersions stabilized by a diblock copolymer: An anomalous viscosity-particle concentration dependence

The rheological study of dispersions of poly(methyl methacrylate) particles stabilized in decane by a steric stabilizer, polystyrene-block-poly(ethyle ne-co-propylene) diblock copolymer, revealed an extremely high apparent vis cosity at low shear rates or even the yield stress at a relatively low volu me fraction of particles (similar to 0.1). This behavior is due to highly i nteracting stabilizer macromolecules anchored to the particle surface. As t he concentration of poly(methyl methacrylate) is further increased. the vol ume fraction of particles also increases, the particle diameter grows, the number of particles is reduced and the viscosity of the dispersion falls. ( C) 1999 The Society of Rheology. [S0148-6055(99)00106-6].