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In order to apply microcapsules as a functional material of cement composites, such as self-healing and heat-transfer-controlling materials, the effect of the addition of microcapsules on the mechanical properties of cement mortar was investigated. Polystyrene microcapsules containing CaCl2 aqueous solution as a microencapsulation substance with monocore and multicore structures were successfully prepared from solid-in-oil-in-water (S/O/W) emulsion by the solvent evaporation method. The compressive strengths of the mortars with and without the microcapsules were measured at various curing times. The compressive strength of the mortar without microcapsules increased with curing time. The compressive strength of the mortar with the microcapsules was lower than that without microcapsules and increased with time. The decrease in the compressive strength increased with the amount of the microcapsules added in the mortar. The self-healing effect of cracked mortar by CaCl2, which would be supplied from the microcapsules due to outer mechanical force making cracks in the mortar and on the microcapsules was not clearly shown in this experiment. However, permeation and leakage of Cl− ion to the surrounding mortar from the microcapsules was observed by mapping analysis of SEM-EDX. [ABSTRACT FROM AUTHOR]

Crosslinked-gel microcapsules immobilized small droplets of phenolic oxime extractant, 1-(2-hydroxy-5-nonylphenyl) ethanone oxime (LIX84-I) were prepared from O/W emulsion using falling-drop method followed by crosslinking of sodium alginate (Na-Alg) by Ca2+ ion and crosslinking of polyvinyl alcohol (PVA) by glutaraldehyde. A lot of fine droplets of LIX84-I were successfully immobilized in the microcapsules. The LIX84-I contents in the microcapsules increased with an increase in the LIX84-I amounts to the aqueous phase. The maximum extracted amounts of Cu(II) increased linearly with the LIX84-I contents with a slope of 1/2 which means two molecules of LIX84-I react with one Cu(II) ion. The extraction rate was not significantly affected by the size of the extractant droplets dispersed in the microcapsules. The microcapsules could be used repeatedly for the extraction and back-extraction of Cu(II). [ABSTRACT FROM AUTHOR]