Effect of polar additives on melt electrospinning of nonpolar polypropylene

Abstract

Melt or solution electrospinning is an effective and direct technique for producing nanoscale fibers. Polypropylene (PP) cannot be easily dissolved at ambient temperature. Thus, it was commonly electrospun in melt state. However, compared with solution electrospun fibers, melt electrospun PP fibers are more uneven with bigger diameters. To remedy this problem, polar additives, namely, stearic acid and sodium stearate were added into pure PP. The effects of the additives were investigated. Results showed that contrasting to those of pure PP, the fiber diameter of PP with 8 wt% stearic acid decreased by 69.3 % (from 5.4 μm to 1.6 μm). The smallest fiber diameter was 600 nm and the smallest average fiber diameter was 1.8 μm when the sodium stearate contents were 10 wt% and 8 wt%, respectively. The addition of polar compounds could alter not only the diameters of PP microfibers, but also the distribution of diameters, the processing current, and even the thermal properties of fibers. The microcosmic mechanisms for these changes were interpreted.

Keywords

• diameter
• microfiber
• non-polar polymer
• sodium stearate
• stearic acid
• crystallization