Melt-electrospinning of polypropylene with conductive additives

In this paper, the feasibility of fabricating polypropylene (PP) nanofibres was investigated using conductive additives such as sodium oleate (SO) and sodium chloride (NaCl) during melt-electrospinning. PP of high melt flow index (MFI = 2000) was used with varying amounts of additives. The effects of amount of additives on the fibre diameter and morphology were investigated. The lowest fibre diameters of 0.371 +/- A 0.106 and 0.310 +/- A 0.102 mu m were achieved with 7 % SO and 5 % NaCl, respectively. The fabrication of nanofibres was attributed to the increase in the electrical conductivity with the introduction of the additives. The increase in the electrical conductivity was greater in the case of NaCl, due to the smaller ionic size of NaCl. Differential scanning calorimetry results showed complex melting behaviour during the heating cycles for the fibres containing SO; and double melting peaks during the second heating cycle for the fibres containing NaCl. X-ray diffraction studies showed the fibres fabricated with the additives contained lower degrees of crystallinity compared to the as-spun fibre and the crystallinity was increased after annealing. The fibres fabricated with the additives contained alpha-form crystals only which did not change after annealing. The fibres fabricated from pure polymer and with the additives were hydrophobic in nature. The hydrophobicity was marginally decreased with the addition of SO and NaCl.