Application of green solvents as a replacement of toxic dimethylformamide in the polylactic acid electrospinning process

Abstract

Nanofibres based on polylactic acid (PLA) have a wide range of applications, including air filtration. They are prepared by electrospinning using toxic solvents as dimethylformamide. This study focused on the use of green solvents to prepare electrospinnable solutions. It was found that a combination of solvents is necessary. A nozzle electrospinning technique was applied to produce PLA nanofibres from optimised dual (ethyl or methyl lactate with acetone) or ternary (cyclopentanone, acetone and ethyl or methyl lactate) solvent system. The prepared nanofibres were evaluated for morphology and quality of nanofibres (SEM), surface wettability (contact angle), filtration properties (automated filter tester) and pore size and distribution (porometry). Potential changes in the chemical composition and the presence of residual solvent were investigated by FTIR, TGA and headspace analysis. It was found that green solvents can substitute dimethylformamide; especially combination of cyclopentanone/ethyl lactate/acetone provides air filtration properties comparable to dimethylformamide/acetone-based systems.