Influence of the solvent on the microencapsulation of an hydrated salt

Microparticles loaded by sodium phosphate dodecahydrate (DSP) were prepared according to the solvent evaporation–precipitation method using various organic solvent and cellulose acetate butyrate (CAB) crosslinked by methylene diisocyanate (MDI) as coating polymer. The effects of the solvent on the capsule morphology and the entrapment efficiency of water-soluble materials were investigated. The surface morphology has been investigated by SEM and it was found that the ‘goodness’ of the solvent, i.e. as defined by solubility parameters, strongly influences the morphology of the microparticles. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were employed to investigate the thermal stability and the thermal properties of these microencapsulated phase change material. The results showed that the thermo-physical properties are strongly dependant on the core content and the synthesis conditions. Thus, the microparticles with high loading content are found suitable for thermal energy storage.