Preparation and characterization of ethyl cellulose-based core-shell microcapsules containing plant oils

In this study, microencapsulated phase change materials based on rapeseed oil (RO) and linseed oil (LO) core and ethyl cellulose (EC) shell materials with various ratios of oil to EC (60:40,70:30 and 75:25) were prepared by solvent evaporation method. Shape and morphology of microcapsules were evaluated using optical microscopy and scanning electron microscopy (SEM). The size distribution of microcapsules was investigated using a particle size analyzer. Zeta potential measurements were performed to find out the proper storage and processing pH for the microcapsules to prevent aggregation. Microcapsules with a regular spherical shape 10-50 mu m in diameter and 0.65-1.55 mu m in shell thickness were successfully synthesized using either ethyl acetate or chloroform as solvent. High yields (85-90%) of spherical microcapsules containing either RO or LO were prepared via freeze-drying method with a fill content of 85-89 wt% as determined by extraction technique. (C) 2011 Elsevier B.V. All rights reserved.