Surfactant-free emulsion polymerization of styrene using crosslinked seed particles

Abstract

The aim of this research was to prepare a monodisperse polystyrene latex without surfactants adsorbed at the particle surface. Conventional polymerization formulations usually lead to large amounts of oligomers. Furthermore, they are characterized by a low reproducibility with respect to particle size. This was overcome by using a seed latex that was crosslinked in order to overcome dissolution in the monomer phase. By adjusting the seed concentration, any desired particle size in the range 0.5-1.2 #m could be obtained. The monodispersity was very good.

The mechanism of particle formation during homogeneous precipitation of zinc sulfide

“…The filtered and washed product powders were redispersed in water and subjected to ultrasonics for 1 h. The measurements were performed with a Coulter LS130. Particle characteristics were visualized by scanning electron microscopy (JEOL JSM 80A) as described previously [8].…”

Conjugated Linoleic Acid/Styrene/Butyl Acrylate Bulk and Emulsion Polymerization for Adhesive Applications

“…With the prohibitive cost of high purity CLA, an affordable CLA containing impurities such as oleic acid (see Figure d) and saturated fatty acids (see Figure e) presented an interesting option for polymerization. Oleic acid has been used as a surfactant replacement in the emulsion homopolymerization of styrene (Sty) without any signs of copolymerization and is also known for its electron trapping ability where the oleic acid radicals are resonance stabilized . Saturated fatty acids are not expected to participate in free radical reactions, other than to impart some viscosity to the reaction medium, because they do not contain the proper reactive sites (i.e., the double bonds) for free radical polymerization.…”

Hydrolyzable‐emulsifier‐containing polymer latices as dispersants and binders for waterborne carbon black paint

“…However, the slow evaporation of water and the persistent surface activity of amphiphiles may inhibit the adhesion to substrates and the formation of continuous films; this leads to a decrease in the performance of the final products in elements such as quick‐drying ability, water resistance, toughness, durability, and other paint qualities . Significant efforts have been made to diminish the amounts of the components or to mask their surface activity; these include surfactant‐free emulsion polymerization, polymeric surfactants, polymerizable surfactants, and fluorine‐ or silicone‐containing polymer latices and surfactants . In most cases, however, posttreatments such as crosslinking and high‐temperature annealing should be required, and moderate amounts of surface‐active components still remain in the final products.…”