Rheology of concentrated multi-sized poly(St/BA/MMA) latices

Four monodisperse latices with particle size of 75, 135, 340 and 477 nm were synthesized. The rheological properties of mixture of the monodisperse latices were investigated as a function of blending ratio, and compared with those of multimodal latices, in a range of shear rate from 0.2 to 100 s(-1). The maximum packing (highest solid contents) was observed at a weight fraction 80% of large particles with respect to total solids contents for both bimodal and trimodal latices, and the lowest viscosity was obtained when the ratio of large to medium to small particles was approximately 80/10/10 (by wt.). It was also demonstrated that this minimum in the viscosity is not strongly dependent on the actual size of each kind of particles present in the multimodal latices.