Electrospun Form-stable Phase Change Composite Nanofibers Consisting of Capric Acid-based Binary Fatty Acid Eutectics and Polyethylene Terephthalate

The four binary fatty acid eutectics of capric-lauric acid (CA-LA), capric-myristic acid (CA-MA), capric-palmitic acid (CA-PA), and capric-stearic acid (CA-SA) were firstly prepared as solid-liquid phase change materials (PCMs); then, the composite phase change nanofibers consisting of CA-based binary fatty acid eutectic and polyethylene terephthalate (PET) were fabricated by electrospinning for thermal energy storage. The maximum mass ratios of fatty acid eutectics versus PET in the nanofibers could reach up to 2/1. The FE-SEM images revealed that the composite nanofibers possessed smooth and cylindrical morphological structure having diameters of about 100-300 nm. The fatty acid eutectic could be uniformly distributed in the three-dimension network structure of the PET nanofibers. The FT-ER results indicated that the fatty acid eutectic and PET had no chemical reaction and exhibited good compatibility with each other. The DSC measurements showed that the prepared composite nanofibers had appropriate phase transition temperatures (about 5-38 degrees C) based upon climatic requirement, whilst the phase change temperatures and the enthalpy values of the composite nanofibers could be adjusted by changing the contents and the types of binary fatty acid eutectics in the nanofibers. The TGA results suggested that the onset thermal degradation temperatures and charred residues at 700 degrees C of the composite nanofibers were lower than those of pure PET nanofibers, but higher than those of fatty acid eutectic, which were caused by the fact that the PET had better thermal stability than fatty acid eutectic.