Formation of Microcapsulated Aluminium Potassium Sulfate Dodecahydrate by Phase Separation Method

Abstract

The aim of this study was to produce microencapsulated phase change materials (PCMs) by simple coacervation method. For PCM KAl(SO4)2.12H2O (Alum) and for coating ethyl cellulose (EtC) and poly(methyl methacrylate) (PMMA) were selected. The spherical core particles of 1.25 – 2 mm size were prepared by pan granulation of Alum-water wet pellets. Shell coating was carried out by two different types of coacervation variants. Process I: EtC polymer coacervation was induced from cyclohexane solution reducing the temperature from 81 °C to 25 °C. The polymer shell on the Alum particles surface was incomplete, because during hardening the polymer coatings was shrunken. Process II: Formation of EtC and PMMA shell coating was induced on Alum core surface by solvent change method. The polymer shell was coacervated from their dichloromethane solution by hexane. The water permeability, i. e. the release of Alum was investigated by conductivity measurements.