Effects of nano-SiO2 on morphology,thermal energy storage,thermal stability,and combustion properties of electrospun lauric acid/PET ultrafine composite fibers as form-stable phase change materials

The ultrafine composite fibers consisting of lauric acid (LA), polyethylene terephthalate (PET), and silica nanoparticles (nano-SiO₂) were prepared through the materials processing technique of electrospinning as an innovative type of form-stable phase change materials (PCMs). The effects of nano-SiO₂ on morphology, thermal energy storage, thermal stability, and combustion properties of electrospun LA/PET/SiO₂ composite fibers were studied. SEM images revealed that the LA/PET/SiO₂ composite fibers with nano-SiO₂ possessed desired morphologies with reduced average fiber diameters as compared to the LA/PET fibers without nano-SiO₂. DSC measurements indicated that the amount of nano-SiO₂ in the fibers had an influence on the crystallization of LA, and played an important role on the heat enthalpies of the composite fibers; while it had no appreciable effect on the phase change temperatures. TGA results suggested that the incorporation of nano-SiO₂ increased the onset thermal degradation temperature, maximum weight loss temperature, and charred residue at 700 °C of the composite fibers, indicating the improved thermal stability of the fibers. MCC tests showed that the heat resistance effect and/or barrier property generated by nano-SiO₂ resulted in an increase of initial combustion temperature and a decrease of the heat release rate for the electrospun ultrafine composite fibers.