Fabrication and characterization of polyacrylonitrile and polyethylene glycol composite nanofibers by electrospinning

Abstract

Thermal energy storage had been recognized as one of the most helpful technologies for the conserving energy. In this investigation, through a combination of polyethylene glycol (PEG) as a phase change material (PCM), and polyacrylonitrile (PAN) as supporting matrix, form-stable composite nanofibers were fabricated by single nozzle electrospinning. The structure, morphology, thermal properties and micro/nano-mechanical properties of the as-prepared nanofibers were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and atomic force microscopy (AFM), respectively. The results showed that PAN and PEG showed good compatibility and no chemical reaction existed between PAN and PEG instead of physical interaction. In addition, PAN/PEG composite nanofibers had a uniform microscopic morphology before thermal cycling, and a certain degree of phase change leakage occurred after thermal cycles with higher PEG content. PAN/PEG(3:2) composite nanofiber membrane had reasonable enthalpy and less morphological change compared to other ratios of nanofiber membranes. The melting and solidifying enthalpies of PAN/PEG(3:2) composite nanofibers before and after thermal cycling were 74.2 J/g and 69.6 J/g, respectively, with relatively high thermal stability and reliability. Furthermore, the thermal regulation ability of the three-layer and five-layer fibers was 5.5 °C and 12.1 °C, respectively. This study suggested that the fabricated composite nanofibers offered proper phase transition temperature range and high heat enthalpy values and hence, have the potential for thermal energy storage applications.