Preparation and Characterization of Cellulose Acetate Microencapsulated N-Octadecane for Thermal Regulation Applications

In this research, a systematic study was carried out to prepare microcapsules with cellulose acetate as a shell polymer and n-octadecane as a core material with a phase separation technique. This study aimed to investigate and clarify conditions for optimal morphology and behavior of these microcapsules for Phase Change Materials (PCMs). The optimal core-shell weight ratio, polymer molecular weight, and emulsification method were investigated. Using cellulose acetate with higher molecular weight (52,000 g/mol) and a core-to-shell weight ratio of 2:1, microcapsules with a high encapsulation efficiency of 86.7%, melting and crystallization enthalpies of 132.33 (J/g) and 91.24 (J/g) were obtained. It was also observed that the optimal method for preparation of the primary emulsion phase was via magnetic stirring in comparison with ultra-sonication (40.9%). The average particle size distribution of microcapsules was 20.48 μm, with an average shell thickness of 0.777 μm. The method used in this study was simple, fast, and low cost-effective. With an easy-to-scale-up feature, and not requiring high temperatures or phase change starters, these novel microencapsulated PCMs are ideal for industrial use.