The Potential for the Direct and Alternating Current-Driven Electrospinning of Polyamides.

Pavel Holec,Jiří Chvojka,Tomáš Kalous,Radek Jirkovec,Jiří Brožek,Ondřej Baťka

doi:10.3390/nano12040665

Pavel Holec, Jiří Chvojka + Show 4 more

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https://doi.org/10.3390/nano12040665

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Abstract

The paper provides a description of the potential for the direct current- and alternating current-driven electrospinning of various linear aliphatic polyamides (PA). Sets with increasing concentrations of selected PAs were dissolved in a mixture of formic acid and dichloromethane at a weight ratio of 1:1 and spun using a bar electrode applying direct and alternating high voltage. The solubility and spinnability of the polyamides were investigated and scanning electron microscopy (SEM) images were acquired of the resulting nanofiber layers. The various defects of the spun fibers and their diameters were detected and subsequently measured. Moreover, the dynamic viscosity and conductivity were also subjected to detailed investigation. The most suitable concentrations for each of the PAs were determined according to previous findings, and the solutions were spun using a NanospiderTM device at the larger scale. The fiber diameters of these samples were also measured. Finally, the surface energy of the fiber layers produced by the NanospiderTM device was measured aimed at selecting a suitable PA for a particular application.

Highlights

Aliphatic polyamides are widely-used thermoplastic polymers [1]
These solutions were prone to rapid precipitation on their surfaces which led to the formation of thin polymeric films, which acted to halt the spinning process
PAs with aliphatic chains lower than 11 could be done by substituting dichloromethane with tetrachloroethane or their suitable mixture. This lowers the solvent’s evaporation rate and allows better controllability of the spinning process and the solution storage. This solvent system would probably not be suitable for PA11 and PA12, limiting the general applicability of the solvent for polyamides

Summary

Introduction

Aliphatic polyamides ( known as nylons) are widely-used thermoplastic polymers [1]. They are synthesized via the polycondensation of an Ω-aminoacid, the polyreaction of a diamine with a dicarboxylic acid or halide and the ring-opening polymerization reactions of lactams [2]. The abbreviations of the various nylons consist of the prefix PA (polyamide) plus numbers that identify the number of carbon atoms between adjacent amide groups. A PA synthesized from a diamine and a dicarboxylic acid (or halide) is identified by two numbers–the first corresponds to the number of carbons between the diamine groups and the second to the number of carbons in the whole of the dicarboxylic acid (i.e., halide) [3]. The aliphatic groups serve to render the whole of the polymeric chain more flexible

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