Abstract
This study aimed at the development and characterization/evaluation of polyethylene glycol (PEG) encapsulated in supporting polymer matrices (e.g., electrospun nanofibres) as innovative form-stable phase change materials (PCMs) for storage and retrieval of thermal energy. Ultrafine phase change fibres consisting of PEG (acting as phase change materials) and polyamide 6 (PA6, acting as supporting materials) were successfully fabricated by electrospinning technique. The effects of PEG amount and two different molecular weights (Mn) of PEG on structural morphology and thermal energy storage/retrieval property of PEG/PA6 ultrafine phase change fibres were systematically studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. The SEM images showed that neat PA6 nanofibres were smooth with cylindrical shape, but the tubercles and/or beads in fibres were observed for PEG/PA6 ultrafine phase change fibres with increasing PEG amount and higher molecular weight of PEG. The average fibre diameters ranged from about 80 to 150 nm and increased with increasing the PEG amount and molecular weight of PEG, which resulted from the increased viscosity and decreased conductivity of composite spin dopes. The DSC results indicated that the enthalpies of melting and crystallization of PEG/PA6 ultrafine phase change fibres increased with increasing PEG amount, and were lower than those of neat PEG powders.