Preparation Of PVDF Nanofibrous Membrane By Coaxial Electrospinning And Its Carbonization

Polyvinyl fluoride (PVDF) nanofibrous membranes with different cross-section morphologies were prepared by coaxial electrospinning in this paper. PVDF/Polyvinyl pyrrolidone (PVP) K30 and PVP K90 were used as shell and core polymers respectively. Core solution with different concentrations of PVP were prepared. Interfacial diffusion phenomena between shell and core solution was analyzed. The effect of the inner solution with different concentrations on mechanical properties, hydrophilicity, and morphologies of PVDF nanofibers were studied. Specific surface area and pore size distribution were tested. Apart from that, porous carbon nanofibers are successfully prepared from the carbonization of PVDF nanofibrous membranes. The variation of the mechanical properties was studied. The structure, specific surface area, and pore size distribution were characterized. The possibility of CO2 capture technology applications of carbon nanofibers was discussed.In the case of a low concentration inner solution, the interfacial diffusion mainly started from the outer solution to the inner solution, the resultant nanofibers showed a net-like cross-section. While in the case of a high concentration inner solution, the interfacial diffusion changed in the opposite direction, and nanofibers showed a hollow cross-section. As the inner PVP was increased, bead nanofibers were reduced and uniform continuous nanofibers were finally obtained. The mechanical strength and hydrophilicity of the nanofibrous membranes were increased. The specific surface area increased and could reach 42.07m2/g, which was the higher than the published PVDF nanofibers. Porous carbon nanofibers were prepared from the carbonization of PVDF nanofibers at 800℃. The specific surface area and pore volume of N2o-C were up to 1380 m2/g and 1.2 cm3/g respectively. And N60-C reached the highest CO2 adsorption uptake of 376.8 cm3/g at 0℃ and P/Po of 1.