Preparation Of Hybrid Pan Nanofibers Containing Functional Mwcnts And Research On The Nano-carbon Fiber

As a reinforcement material with super performance, carbon fibershave already been used in national defence, energy, traffic, physicalequipments, and so on. The perfect degree of microstructure is the keyfactor to influence their mechanical property. As one of the importantprecursor, polyacrylonitrile (PAN) has many good characters. There aremany researches which focus on how to improve PAN precursor andfinally obtain excellent carbon fibers. Through electrospinning,nanofibers can be realized to minimize structural defects. In this paper,hybrid PAN nanofiber sheets with different loading of functionalmulti-walled carbon nanotubes (MWCNTs) were fabricated throughelectrospinning. Tensile force was used during the heat treatment.Through ameliorating technical condition and equipments, nano-carbonfibers with good microstructure were prepared under1100℃and1400℃HTT. And lithium battery and composite material were also obtained byusing the prepared nano-carbon fiber. Scanning electron microscopy (SEM), polarized FT-IR spectroscopy,transmission electron microscopy (TEM), Raman spectroscopy, X-raydiffraction (XRD) and the tensile test were adopted to study themicrostructure and mechanical property of the hybrid electrospunnanofiber. The diameter of PAN nanofibers was decreasing with theadding of MWCNTs, but the sample containing5wt%MWCNTsdisplayed a diameter mutation. The experimental results showed thatadding MWCNTs into the polymer was propitious for the orientation ofmolecular chains. The most of MWCNTs embedded in the PAN andaligned along the fiber axis. When the concentration of MWCNTs wasbelow5wt%, the tensile strength and modulus of PAN nanofibers wereboth enhanced with the loading of MWCNTs, which respectively reachedto88.6MPa and3.21GPa after adding3wt%MWCNTs.It was found that adding MWCNTs and increasing the heat treatmenttemperature were both propitious to improve the crystal property ofcarbon nanofibers. The electrical conductivity of nano-carbon fiberspossessed anisotropy, and increased with higher heat treatmenttemperature, which respectively reached35.2S/cm,41.3S/cm at differentdirection with1wt%MWCNTs and1400℃heat treatment temperature.The first discharge and charge capacity of nano-carbon fiber sheets with3wt%MWCNTs respectively reached606.0mAh·g-1and574.2mAh·g-1.After30cycles, the reversible capacity was569.9mAhg-1. The modulus of elasticity and storage modulus of epoxy resin were both enhanced afteradding the prepared hybrid nano-carbon fiber.