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.