Cellulose microfibers as versatile support for shape-stable composites with thermoregulating properties

Abstract

Affordable and clean energy is one of the main goals of the sustainable development of modern society. The thermal energy from natural sources has a great potential for implication in energy management cycles due to its abundance and direct affordability. Phase change materials (PCMs) offer an exciting way to facilitate energy consumption from renewable sources and develop responsive energy management strategies by storing and releasing thermal energy as latent heat of reversible phase transitions. Organic PCMs are attractive due to their high latent heat storage capacity and long-term cyclic stability. However, they suffer from the lack of shape stability limiting their employment in bare form. In this work, we propose a simple approach to prepare shape-stable composite PCMs with high latent heat storage capacity by adsorption of organic PCM (stearic acid) onto the surface of cellulose microfibers (MFC). The structure, surface morphology, and composition were studied by SEM, confocal microscopy, and FTIR analysis. Latent heat storage performance, cyclic and thermal stability were studied with differential scanning calorimetry and thermogravimetric analysis. The shape stability of the composite fibers was evaluated by the material leakage test at various temperatures. We found out that the stearic acid couples with cellulose surface by physical adsorption forming the stable layer following the fiber morphology without any additional treatment of cellulose fibers. The composites demonstrate tunable latent heat storage performance and good cyclic stability. The confinement of stearic acid onto the MFC surface effectively prevents its leakage during the solid-liquid phase transition and preserve thermoregulating properties under temperatures comparable to the melting point of stearic acid. Finally, we have evaluated the ability of the prepared composite fibers to act as functional thermoregulating additives by the inclusion into commercially available cement mortar mix.
D.V. Voronin acknowledges the support of RFBR, project number 19-33-60016. K.A. Cherednichenko and V. Vinokurov acknowledge the support of the Ministry of Science and Higher Education of the Russian Federation in the framework of the state task in the field of scientific activity; subject number FSZE-2020-0007 (0768- 2020-0007).


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Denis Voronin
National University of Oil and Gas «Gubkin University»
Russian Federation

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