Preparation And Characterization Of Phase Change Materials Based On PAN

In this study, waste polyacrylonitrile (PAN) fiber as the main object has been investigated. Firstly, the hydrolyzate of PAN fiber (HPAN) was preparated by the process of alkaline hydrolyzation PAN fiber in different conditions. HPAN-g-PEG phase change material (PCM) was prepared by the methods of chemical grafting between HAPN and PEG Secondly, single component or binary fatty acids as phase change media, PAN as framework material, N,N-dimethylformamide (DMF) as solvent, prepared the PAN/fatty acids solid-solid PCM and fibers.The structure, crystallization property, thermal property, insulation property and mechanical property of HPAN-g-PEG PCM, PAN/SA PCM and fiber, PAN/binary of fatty acids PCM and fiber, PAN/binary of fatty acids PCM and fiber improved by zeolitemolecularsieve (ZMS) were investigated by fourier transform infrared spectroscopy (FTIR), polarizing optical microscope (POM), scanning electron microscope (SEM), differential scanning calorimeter (DSC), temperature-recording instrument, single fiber electronic tensile strength tester and dynamic mechanical analyzer (DMA).The results showed that the amide bond existed in hydrolyzate polyacrylonitrile, polyether chain existed in HPAN-g-PEG, PEG and HPAN-g-PEG had different crystal structure under different temperature. The melting temperature of HPAN-g-PEG increased with the increase of the molecular weight of poly (ethylene glycol) and the amount of catalyst, and the latent heat increased with the increase of the molecular weight of poly (ethylene glycol), which was up to106J/g, and the holding time was about4.5minutes.The phase transition enthalpy of PAN/SA PCM was more than115J/g, the phase transition temperature and phase transition enthalpy of the PCM increased with the increase of the mass percent of SA, the PCM had good insulation property, whose holding time was about6minutes. The thermal insulation property remains unchanged after several rounds of thermal cycling. The transition enthalpy of PAN/SA fiber reached48.84J/g, besides PAN/SA fiber had good thermal insulation properties compared with PAN fiber. And the mechanical properties of PAN/SA fiber dried quickly at110℃hot air was higher than that dried at room temperature.The phase transition enthalpy of PAN/binary fatty acids PCM reached to135.8J/g, the crystallization temperature was about25℃, and the soaking time was about17.7minutes. The thermal insulation property remains unchanged after several thermal cycling. In PAN/binary of fatty acids fiber, the melting temperature of phase change media was41.88℃, melting enthalpy was31.75J/g, the crystallization temperature was28.61℃, the crystallization enthalpy was17.99J/g. The phase change fiber dried at110℃hot air had higher fiber breaking strength than that at room temperature. Furthermore, the strength increased with the increase of the PAN components in fiber matrix. In comparison, the crystallization enthalpy of PAN/binary fatty acids improved by ZMS achieved to125.22J/g, but the crystallization temperature decreased to17℃and the holding time was about1480s.This study not only has achieved the recycling of waste PAN fiber, turning waste into wealth, but also provides the community with a new energy-saving material, which is a new project of low cost, high efficiency, adequate resources, and has broad prospects for development.