Fully bio-originated latent heat storing calcium alginate microcapsules with high coconut oil loading

Abstract

Latent heat storing calcium alginate microcapsules were manufactured by a repeated interfacial coacervation/crosslinking method. By using a high-viscosity sodium alginate for the capsule formation, the paraffin phase change material (PCM) content was substantially enhanced related to the recently developed procedure. The maximization of PCM loading was achieved using experimental design for paraffin containing microcapsules. The microcomposites were optimized for 81.5% PCM content with uniform size of 2.20 ± 0.14 mm. In some applications e.g. packaging, the biodegradable character of the materials is especially beneficial, hence for the manufacture of entirely eco-friendly heat storing microcomposites coconut oil PCM was microencapsulated by the same procedure. The process originally developed and optimized for paraffin was scaled-up by two orders of magnitude, accordingly, the outstanding PCM content was reproduced also with coconut oil (average value 81.1%). The high PCM content was reflected also in the heat storing capacity measured by differential scanning calorimetry. The easily upscalable, spherical and core/shell structured, entirely biocompatible microcapsules with thermally stable calcium alginate coating could be developed for industrial application.