Lignin Modification with Carboxylic Acids and Butyrolactone under Cold Plasma Conditions

Abstract

The modification of organosolv lignin powder (ALCELL) with different carboxylic acids such as oleic, lactic, and butyric acids and butyrolactone under cold plasma discharge has been performed. The X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and 1H NMR spectroscopy, scanning electron microscopy (SEM), and thermal methods (differential scanning calorimetry (DSC) and thermogravimetry (TG)) proved that the lignin modification took place. The structure, morphology and thermal properties are specific for each kind of product obtained. The modification degree determined on the basis of XPS data varies from 4 to 13% depending on reagent used. The significant changes in the thermal properties indicate that the modification by cold plasma affected also some bulk properties. This is the case mainly for modification with butyric acid and butyrolactone. It was concluded that the cold plasma modification is an efficient and eco-friendly technique able to produce new valuable products from lignin, widening its compatibility with various polymers and also its applications.

Bromide-Based Ionic Liquid Treatment of Hardwood Organosolv Lignin Yielded a More Reactive Biobased Polyol

“…Similarly, Br and N signals were not detected following XPS analysis of the recovered, [BMIM]­Br-treated OS-HW (Figure A). High-resolution XPS further fitted the C 1s peaks into the following three groups: C–C/CC (285 eV), C–OH (286 eV), and CO/O–CO (288–289 eV) (Figure B,C) . Although the XPS analysis is not a quantitative technique, the relative increase in the C–OH group (∼10%) in the IL-treated lignin corroborated the increase in OH content measured by 31 P NMR (Table ).…”

“…Highresolution XPS further fitted the C 1s peaks into the following three groups: C−C/CC (285 eV), C−OH (286 eV), and CO/O−CO (288−289 eV) (Figure 3B,C). 46 Although the XPS analysis is not a quantitative technique, the relative increase in the C−OH group (∼10%) in the IL-treated lignin corroborated the increase in OH content measured by 31 P NMR (Table 1). In all, the FTIR, 1 H NMR, and XPS analyses confirmed the purity of the recovered [BMIM]Br, reaching an important milestone toward an affordable, effective IL treatment for lignin via recycling.…”

Formulation of Multifunctional Materials Based on the Reaction of Glyoxalated Lignins and a Nanoclay/Nanosilicate

“…This is in accordance with the S/G ratios previously discussed in Section . Between 8 and 9 ppm, protons derived from phenolic hydroxyl groups are normally reported. , To confirm the presence of the mentioned groups, the lignin samples were added to trifluoroacetic acid (TFA) prior to the 1 H NMR analysis. TFA is known to react with alcohols through the hydroxyl groups, leading to the esterification of the polymer .…”

Plasma technology for lignocellulosic biomass conversion toward an electrified biorefinery

“…Plasma-assisted lignin functionalization has also been employed to improve its processability and interaction with other polymers, thus enabling its upgrade to functional materials. Nistor et al 163 and Chirila et al 164 modified organosolv lignin by carboxylic acids in an RF plasma and improved its hydrophilicity and solubility in aqueous and alkaline solutions, and decreased its particle size. Zhou et al 159 examined the effect of a low-pressure oxygen plasma treatment on the glass transition temperature T g of enzymatic hydrolysis lignin.…”