Effect of viscosity of shell solution on the content of solid powder as core material in microencapsulation by the drying‐in‐liquid method

Abstract

Solid powder generating minus ion was microencapsulated by polystyrene with the drying-in-liquid method. In the microencapsulation, (R)-(þ) limonene as the solvent for polystyrene and ethylene glycol as the continuous phase were adopted instead of the conventional organic solvent such as dichloromethane, benzene and toluene, and water, respectively. It was mainly investigated whether the solvents adopted here could be applied to the drying-in-liquid method or not and how the viscosity of the shell solution and the oil soluble surfactant affected the content of core material. The oil soluble surfactant made hydrophilic solid powder more hydrophobic and resulted in an increase of the content. Microcapsules containing solid powder could be prepared with the drying-in-liquid method using (R)-(þ) limonene and ethylene glycol. An increase in the viscosity of the shell solution repressed the movement of solid powder particles in a droplet of the shell solution during the microencapsulation process and resulted in the higher content.

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

“…These tiny holes may be formed by rapidly removing St of the solvent for PS at the drying‐in‐liquid method …”

“…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.…”

“…Until now, the various fine inorganic and organic solid particles have been microencapsulated by the chemical methods such as the suspension polymerization method, [6] the miniemulsion polymerization method, [7][8][9][10][11][12][13] the soap-free emulsion polymerization method, [14][15][16] and the dispersion polymerization method, [17,18] and by the physicochemical methods such as the coacervation method [19] and the drying-in-liquid method. [20] 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.…”

Preparation and characterization of microcapsules containing particulate phosphorescent agent with suspension polymerization

“…Various fine solid particles have been microencapsulated by the chemical methods such as the suspension polymerization method [5] , the miniemulsion polymerization method [6][7][8][9][10][11][12] , the soap free emulsion polymerization method [13][14][15] and the dispersion polymerization method [16,17] and by the physicochemical methods such as the coacervation method [18] and the dryingin-liquid method [19] .…”