Single-Solvent Fractionation and Electro-Spinning Neat Softwood Kraft Lignin

Abstract

This paper reports on the production of electro-spun nanofibers from softwood Kraft lignin without the need for polymer blending and/or chemical modification. Commercially available softwood Kraft lignin was fractionated using acetone. The acetone-soluble lignin (AcSL) had an ash content of 0.06 wt %, a weight average molecular weight of 4250 g·mol–1 along with the polydispersity index of 1.73. The corresponding values for as-received lignin (ARL) were 1.20 wt %, 6000 g·mol–1, and 2.22, respectively. The AcS was dissolved in a binary solvent consisting of acetone, and dimethyl sulfoxide (2:1, v/v) was selected for dissolving the AcSL. Conventional and custom-designed grounded electrode configurations were used to produce electro-spun neat lignin fibers that were randomly oriented or highly aligned, respectively. The diameter of the electro-spun fibers ranged from 1.12 to 1.46 μm. After vacuum drying at 140 °C for 6 h to remove the solvents and oxidation at 250 °C, the fibers were carbonized at 1000, 1200, and 1500 °C for 1 h. The carbonized fibers were unfused and void-free with an average diameter of 500 nm. Raman spectroscopy, scanning electron microscopy, and image analysis were used to characterize the carbonized fibers.

Lignin-Decorated SiO2 Nanoparticles for Skin Cleansing Applications

“…In addressing the aforementioned issues, the structuring of lignin presents a promising solution. Earlier research conducted by our research team introduced a technique for producing absolute nanoscale lignin particles through single-solvent internal assembly . Building on this, our research suggests a new method to obtain unique skin-cleansing materials with a flaky structure for skin cleansing applications.…”

“…Earlier research conducted by our research team introduced a technique for producing absolute nanoscale lignin particles through singlesolvent internal assembly. 11 Building on this, our research suggests a new method to obtain unique skin-cleansing materials with a flaky structure for skin cleansing applications. By combining lignin nanoparticles with silica nanoparticles through a rapid bonding grafting process, we achieve a patchy lignin composite material (Scheme 1).…”