Understanding solubility, spinnability and electrospinning behaviour of cellulose acetate using different solvent systems

Abstract

The purpose of this study is to understand the solubility and spinnability of cellulose acetate (CA) and its electrospinning behaviour in different solvents. As the process of electrospinning and the corresponding fibre properties are primarily governed by the solvents used, a systematic study of the selection of solvent systems using the solubility parameters of Hildebrand and Hansen along with a Teas chart for a particular polymer is essential for the better optimization of the process. It appeared from the Teas chart that higher dispersion force \((f_{\mathrm{d}})\) and lower hydrogen bonding force \((f_{\mathrm{h}})\) are convenient for both the solubility and spinnability of CA in single solvent of acetone and binary solvent of 2:1 acetone/N,N-dimethylacetamide (DMAc). The viscosity of the solutions escalated with increasing concentration of CA due to polymer chain entanglement which in turn favoured fibre formation. Among the solvent systems used in this work, field emission scanning electron microscopy arrayed the electrospun CA fibres using pure acetone as a solvent produced both cylindrical- and ribbon-shaped fibres of a diameter of 1 \(\upmu \)m, whereas CA in 2:1 acetone/DMAc yielded smooth bead-free cylindrical fibres of diameter in the range of 250–350 nm and CA in 3:1 acetic acid/water formed fibres with beads. Rheological analysis showed that fibre formation improved with increasing viscosity of CA solution. Electrical conductivity measurement of the CA solutions depicted that with an increase in CA concentration, fibre diameters were increased, whereas the conductivity decreased. Also, attenuated total reflectance–Fourier transform infrared spectroscopy confirmed the major peaks of CA for all the electrospun samples.