Encapsulation of aluminum flakes by dispersion polymerization of styrene in a nonaqueous system with reactive surfactants

Abstract

Dispersion polymerization of styrene in ethanol was carried out to encapsulate aluminum flakes. The effects of three reactive surfactants, two anionic and one nonionic, were investigated. It was confirmed prior to encapsulation that these surfactants did not polymerize by themselves but did promote polymerization of styrene. The capsules obtained were characterized with respect to the morphology and mean size. The encapsulating efficiency of the polymer of the wall material, the wall thickness, and the molecular weight distribution were measured. The effects of the concentrations of styrene monomer and reactive surfactants on these characteristics were determined and discussed. Aluminum flakes were coagulated to form secondary particles and they were covered with fine polymer particles, which were precipitated in the continuous phase. To improve encapsulation, the auxiliary addition of nonionic surfactant was attempted. By controlling those concentrations, capsules covered with polymer layer were prepared.

The dispersion and polymer coating of ultrafine aluminum powders by the Ziegler Natta reaction

“…To prevent its formation, several researchers have proposed different coating approaches. Among them are coating by carbon deposition (Ermoline et al 2002), stearic acid and aluminum diboride deposition (Kwon et al 2003), polyvinylidene fluoride deposition by SCF carbon dioxide (Glebov et al 2001), and polystyrene polymerization (Kimura et al 2001). In this work, we report on an in-situ polymerization reaction to graft a layer of polyethylene on nanosize aluminum particles.…”

Microencapsulation of phosphor particles with the drying‐in‐liquid method in parallel with the suspension polymerization method and effect on afterglow luminance property

“…Until now, the various fine inorganic and organic solid particles have been microencapsulated by the chemical methods such as the suspension polymerization method, the miniemulsion polymerization method, the soap‐free emulsion polymerization method, and the dispersion polymerization method, and by the physicochemical methods such as the coacervation method and the drying‐in‐liquid method …”

“…Among them, the soap‐free emulsion polymerization method, the dispersion polymerization method, and the coacervation method are suitable to microencapsulation of a solid particle, and the others are suitable to microencapsulation of many solid particles at once. These microencapsulation methods are used properly to suit the desired functions of microcapsules and the shell material species . Especially, the drying‐in‐liquid method is superior for microencapsulating many solid particles at once because of easy operation and extensive selectivity of polymeric shell materials.…”

Preparation of Polymer Composite Particles by Phase Separation Followed by Suspension Polymerization

“…For example, as the typical in-situ polymerization methods, there are the suspension polymerization method [9], the mini emulsion polymerization method [10] [11], the soap free emulsion polymerization method [12] and the dispersion polymerization method [13].…”