Study On Preparations Of Hollow Submicro-Fiber And Porous Fiber By Coaxial Electrospinning

In this paper, hollow submicro-fiber, porous fiber and porous fiber-based filtration material have been prepared. Polystyrene (PS) hollow submicro-fiber and PS porous fiber have been successfully prepared by coaxial electrospinning technique with two polymer solutions, polystyrene/DMF and poly(vinyl pyrrolidone)/ethanol, followed by a removal of poly(vinyl pyrrolidone); PVP(TiO2)/PLA compound fiber and nylon-6porous fiber also have been prepared by changing materials of shell layer and core layer spinning solution; Nylon-6porous fiber-based filtration material also has been prepared with a use of Nylon-6porous fiber as inner layer of the sandwich structure material.The parameters having effects on the formation of compound Taylor cone and micro-morphology of the compound fiber, such as the viscosity of spinning solution of shell layer and core layer, interfacial tension of interlayer between shell layer and core layer, voltage, the relative (inner-to-outer) flow rate value (K), were also studied and the optimal coaxial electrospinning condition was selected. Shell-Core structure of compound fiber, cross-section morphology and average fiber of PS hollow submicro-fiber and PS porous fiber were characterized by SEM and TEM; Specific surface area and average pore size of PS hollow submicro-fiber and PS porous fiber were characterized by specific surface area analysis instrument and porous medium surface area analyzer. The results show that the stable compound fiber can be formed in the voltage range14.00kV～16.00kV, the relative (inner-to-outer) flow rate value (K) range0.1-0.7, the PS hollow submicro-fiber can be formed by a removal of PVP of the fiber. Diameter of PS hollow submicro-fiber decreased and specific surface area of PS hollow fiber increased with an increase of K value; when K value range is0.8～1.0, and PS submicro-porous fiber can be formed by a removal of PVP, and pore size and total pore volume PS submicro-porous fiber increase with an increase of K value; a fiber of PVP(TiO2)/PLA via a coaxial electrospinning technique have no beads, this is possible due to the solutions which have a high viscosity and a lower interfacial tension.Filtration performance of porous fiber-base filtration material was studied, the filtration efficiency of the Nylon-6porous fiber-base filtration material for the dust in the diameter more than7micrometers can reach100%.