The aim of this study was to improve dispersion stability of calcium carbonate (CaCO3) nanoparticles in aqueous medium using alkyl polyglucoside (APG). One hundred milligrams of CaCO3 nanoparticles was mixed with 30 mL of deionized water. Thereafter, APG was dissolved into the CaCO3 nanoparticle mixtures at approximate 0, 0.1, 0.3, 0.5, 0.7, and 0.9%, and subsequently, pH was adjusted to 7.0 and 10.0. Afterward, all CaCO3 nanoparticle mixtures were dispersed by ultrasonic processing treatment for 10 min. Dispersion stability and physicochemical properties of the CaCO3 nanoparticle mixtures were observed by measuring the change of absorbance and mean diameter for 96 h as well as the initial zeta-potential. As results, initial zeta-potentials of the CaCO3 nanoparticles in deionized water at pH 7.0 and 10.0 showed approximately +20 and 0, respectively. The positive surface charge at pH 7.0 had unfavorable impact on the adsorption of APG onto CaCO3 nanoparticles in the aqueous suspensions because APG is nonionic surfactant. Among all samples at pH 10, CaCO3 nanoparticles in 0.5% APG aqueous solution showed the smallest initial mean diameter and the slowest increase in mean diameter and decrease in absorbance. In conclusion, the pH 10.0 and 0.5% APG concentration was the most desirable condition in order to improve dispersion stability of CaCO3 nanoparticles in an aqueous medium.

Alkyl polyglucosides were synthesized by solvent-free glycosidation using ultrasonic emulsification. We examined glycosidation conditions of fatty alcohol with glucose hydrate and anhydrous glucose in the presence of p-toluenesulfonic acid. Glucose was emulsified in a molar excess of fatty alcohol for 20 minutes with a ultra-sonicator at room temperature and converted in a stirred reactor to more than 95% polyglucoside within 2.5~3.5 hr under 20~30 mmHg at 110℃ with a three-fold molar ratio of fatty alcohol to glucose in the presence of 1mol% p-toluenesulfonic acid. It was possible to obtain a polyglucoside mixture of HLB 13 consisting of 65% monoglucoside and 35% oligoglucoside with less than 1% of fatty alcohol.