The effect of the surfactant adsorption layer on the growth rate of the polyurethane capsule shell

Microcapsules containing limonene oil as a core material were prepared by interfacial polycondensation polymerization between isocyanate and amine. In the experiment, emulsions were made by dispersing limonene oil in the aqueous solution of poly(vinyl alcohol) and then, microencapsulation was started. It was investigated how the adsorption layer of poly(vinyl alcohol) affected the growth rate of microcapsule shell. The growth rate of the microcapsule shell was estimated by measuring the transient shell thickness of microcapsules which were sampled out at anytime of microencapsulation process. It was found that the growth rate of microcapsule shell decreases with the adsorption amount of poly(vinyl alcohol) on the interface.