Leakage-proof microencapsulation of phase change materials by emulsification with acetylated cellulose nanofibrils

• Published in: Carbohydrate polymers 2021-02, Vol.254, p.117279, Article 117279
• Main Authors: Shi, Xuetong, Yazdani, Maryam R., Ajdary, Rubina, Rojas, Orlando J.
• Format: Article
• Language: English
• Subjects: Acetylated cellulose nanofibril; Acetylation; Capsules; Cellulose - analogs & derivatives; Cellulose - chemistry; Cellulose - ultrastructure; Colloids; Drug Stability; Emulsions; Encapsulation; Heat storage; Hot Temperature; Microscopy, Electron, Scanning; Nanofibers - chemistry; Nanofibers - ultrastructure; Paraffin; Paraffin - chemistry; PCM; Phase change material; Phase Transition; Rheology; Suspensions; Thermogravimetry
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2020.117279

Acetylated cellulose nanofibrils are usedto encapsulate paraffin, forming shape-stable phase changesystemssuitable for thermal energy storage and conversion. [Display omitted] •Acetylated nanocellulose enables shape and thermally-stable paraffin encapsulation.•The leakage-free phase change material withstands cyclic melting/solidification.•A high melting enthalpy (173 J/g) and reduced supercooling (by 53 %) are observed.•The results indicate stable and durable solution for energy conversion/storage. We use acetylated cellulose nanofibrils (AcCNF) to stabilize transient emulsions with paraffin that becomes shape-stable and encapsulated phase change material (PCM) upon cooling. Rheology measurements confirm the gel behavior and colloidal stability of the solid suspensions. We study the effect of nanofiber content on PCM leakage upon melting and compare the results to those from unmodified CNF. The nanostructured cellulose promotes paraffin phase transition, which improves the efficiency of thermal energy exchange. The leakage-proof microcapsules display high energy absorption capacity (ΔHm = 173 J/g) at high PCM loading (up to 80 wt%), while effectively controlling the extent of supercooling. An excellent thermal stability is observed during at least 100 heating/cooling cycles. Degradation takes place at 291 °C, indicating good thermal stability. The high energy density and the effective shape and thermal stabilization of the AcCNF-encapsulated paraffin points to a sustainable solution for thermal energy storage and conversion.