n-Eicosane-Impregnated nonwoven phase change mats of electrospun Poly(ethylene oxide)/Poly(methyl methacrylate) blended fibers

The ever-increasing energy demand led scientists turn to more efficient, environmentally friendly, and renewable technologies. Phase change materials (PCMs) are gaining popularity in the field of passive thermal energy storage. In the current work, polyethylene oxide/poly (methyl methacrylate) (PEO/PMMA) electrospun fibers were employed as encapsulation matrices for n-eicosane and their physicochemical properties were tested, aiming to develop stable phase change fibers (PCFs). The effect of the n-eicosane content on the morphology and thermal properties of the form-stable PEO/PMMA/n-eicosane PCFs was extensively investigated by using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). The melting and crystallization enthalpy of PEO/PMMA/n-eicosane remained unchanged during the first and second cycle. After 30 heating-cooling cycles, the samples with 2 and 5 wt% n-eicosane exhibited inferior thermal reliability, while no temperature and enthalpy change were observed after the thermal cycling of PCF with 7.5 and 10 wt% n-eicosane content, thus rendering these systems suitable materials for thermal energy storage applications. The most promising system was the one containing a 10 wt% n-eicosane, due to the higher crystallization enthalpy (184 J/g) and the stabilization of the melting and crystallization peaks for all cycles. The degradation kinetics were investigated for n-eicosane, the pristine PEO/PMMA fibers and the PEO/PMMA/n-eicosane fibers with a 10 wt% n-eicosane content. Moreover, the Activation Energy (Ea) and the pre-exponential factor (A) were calculated using the Friedman and Vyazovkin methods whereas the reaction mechanisms were studied using the model fitting method.