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The possibility of using composite fibers with phase change properties as a thermoregulating additive to dry building mixes (mortar mix) with the possibility of accumulating thermal energy under the action of sunlight and a high-frequency alternating magnetic field is studied. Composite fibers were obtained by adsorption of the organic phase-change material eicosane on fibers of microfibrillar cellulose modified with magnetite nanoparticles. The obtained composites demonstrated specific values of stored thermal energy in the range of 129-148 J/g, depending on the content of eicosane in their composition. It is shown that the addition of 10–15% wt. of composite fibers to the dry building mix makes it possible to store and release thermal energy in hardened samples in a temperature range of 27-43°C, corresponding to melting and crystallization of the eicosane in the structure of the composite fibers. It was shown that addition of the composites affects the dynamics of heating under the action of artificial sunlight and subsequent cooling: the samples with added fiber showed more intense heating and slower cooling compared with control samples when the temperature reached 35°C. Samples of the hardened mixture with addition of the composite fibers also exhibited the ability to accumulate thermal energy when exposed to a high-frequency alternating magnetic field with its subsequent sustained removal. [ABSTRACT FROM AUTHOR]

Biopolymeric materials appear as promising eco-friendly and biodegradable matrices for the preparation of composite materials. In this work, G. lucidum, T. hirsuta, P. eryngii, F. velutipes, G. applanatum, L. edodes, and H. erinaceus fungi strains were studied and the fastest-growing fungi strains were revealed. The growth rate and the morphology of formed mycelium were studied depending on the fungi strain type and employed feeding substrate (malt agar, cellulose microcrystals, cellulose microfibrills). It was shown that the mycelium of G. lucidum and T. Hirsuta grown on cellulose microfibrils appears as intertwined hyphae with narrow diameter size distribution and has an optimal morphology as a substrate for the preparation of fibrous composite materials.. [ABSTRACT FROM AUTHOR]