Ultrafine polypropylene (PP) fibers as oil sorbents were fabricated via a needleless melt‐electrospinning device and were characterized by scanning electron microscopy and contact‐angle analysis. PP fibers of various diameters and porosities were obtained by the manipulation of the applied electrical field. The effects of the fiber diameter and porosity on the oil‐sorption capacity and oil‐retention behavior were investigated. The experimental results demonstrate that for fiber diameter on the microscale, the porosity played a paramount role in determining the oil‐sorption capacities. The maximum oil‐sorption capacity of the resulting PP fibers with regard to motor oil and peanut oil were 129 and 80 g/g, respectively; these values were approximately six to seven times that of commercial PP nonwoven fabricated through the melt‐blown method. In addition, even after seven sorption/desorption cycles, the oil‐sorption 

In this study, polypropylene was mixed with three different pore-forming agents (nanometer cal-cium carbonate, paraffin and inorganic hybrid salts) to form three blended systems which were used to pro-duce composite fibers by self-made melt differential electrospinning device. Polypropylene fibers withrough surface and microporous were prepared after removing above-mentioned pore-forming agents. Thesurface morphological structures of these polypropylene fibers were characterized. Results showed that theaverage diameter of polypropylene-nanometer calcium carbonate composite fibers (8.22 μm), polypropylene-paraffin composite fibers (8.67 μm) and polypropylene-inorganic hybrid salts composites fiber (6.08 μm) wasless than pure polypropylene fibers (12.10 μm); the diameter of composite fibers was not reduced with theincreasing of melt index; polypropylene fibers without nanometer calcium carbonate comprised microporoushaving different sizes and uneven distribution, polypropylene fibers without paraffin had rough surface andstrip or bulk dents, polypropylene fibers without inorganic hybrid salts comprised microporous having rela-tively small sizes and even distribution. These three polypropylene fibers were all able to increase the hydro-philicity or hydrophobicity of materials. Furthermore, the number of Taylor cone was increased by using as-sistant air flow. Taylor cone contributed to the stability of jet flow and the refining of composite fibers whenTaylor cone increased to a certain number.