Synthesis of PVAc/SiO2 latices stabilized by silica nanoparticles

This paper presents a method for the preparation of raspberry-like organic-inorganic composite spheres with poly(vinyl acetate) (PVAc) as core and nanosilica particles as shell. A small amount of anionic reactive surfactant, 3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt (HAPS), was used as co-stabilizer and nanosilica particles were adsorbed onto the growing latex core in aqueous medium via the formation of hydrogen bonds between nanosilica particles and PVAc particles. TEM indicated that the hydrogen bonds between nanosilica particles and PVAc were strong enough for the formation of long-stable composite spheres with raspberry-like morphology. Influences of some synthetic parameters, for instance, type of silica sol, initial silica amount, and different kinds of low-molecular-weight surfactant, on the morphology of the composite spheres and properties of the latex films were studied in detail. A possible formation mechanism of the composite spheres was also proposed. (C) 2007 Elsevier Inc. All rights reserved.