Development for preparation of nanofibers using polylactic acid and biomass lignin via electrospinning process

Abstract

Currently, large quantities of scrap materials from processing biomass in the agricultural industry such as bagasse (BG), palm kernel shell (PKS) and para-wood (PRW) are thrown away, from which useful lignin can be extracted. This research investigated the preparation of nanofibers by electrospinning technique using lignin from 3 different sources and polylactic acid (PLA) dissolved in a solvent mixture between tetrahydrofuran (THF) and dimethylformamide (DMF). The effects of all applicable parameters related to nanofiber and solvent compositions as well as electrospinning conditions, namely, the source of lignin and its weight ratio to PLA, composition of solvent mixture, polymer solution concentration, distance between the injecting needle tip and collector, ejection rate, and applied voltage for electrospinning, were studied. The resulting nanofiber morphology, surface smoothness, average fiber diameter and size distribution were determined by scanning electron microscope. By varying the parameters methodically, it was found that the optimum parameters for producing smooth-surfaced and relatively uniform nanofibers were: ratio of biomass lignin to PLA 3:1 (w/w), THF:DMF 50:50 (v/v) for solvents, ejection rate 0.5 ml/min, distance from needle tip to collector 10 cm, voltage 16 kV. More specifically, the range of fiber diameters for BG/PLA, PRW/PLA and PKS/PLA was observed to be 400-1,000 nm, 200- 1,600 nm and 900-2,400 nm, respectively. The biodegradable spun nanofibers may be used in the matrix for PM2.5 face masks (fine particle filtration) and gas adsorption.