Electrospun methyl stearate/PET form-stable phase change composite nanofibres for storage and retrieval of thermal energy

Abstract

This study is focused on the fabrication and characterisation of morphological structures, thermal and mechanical properties of electrospun methyl stearate (MES)/polyethylene terephthalate (PET) composite nanofibres as form-stable phase change materials. Field-emission scanning electron microscope images illustrated that the MES component was well dispersed and encapsulated into the three-dimension porous network structure of the PET supporting matrices during the electrospinning process. Maximum weight percentage of the MES combined in composite nanofibres was found as 50 wt.% without the leakage of MES in liquid state even when it was heated over the melting temperature of MES powder. FTIR analysis revealed no chemical reactions between the MES molecules and the PET molecules. From differential scanning calorimetry analysis, electrospun MES/PET phase change composite nanofibres with different mass ratios processed appropriate phase transition temperatures of about 19–47 °C, and the maximum melting and freezing enthalpies could reach up to 90.43 and 88.03 kJ/kg, respectively. Thermogravimetric analyses’ results suggested that electrospun MES/PET phase change composite nanofibres exhibited good thermal stability during the phase change temperature range, and their thermal stability was improved due to the introduction of PET supporting matrices having the better thermal stability. In addition, the results of tensile testing indicated that electrospun MES/PET phase change composite nanofibres gradually lost ductile and exhibited smaller elongations with the increase in MES content, whereas their tensile strength showed an increased tendency from 6.0 to 7.8 MPa.