New Insights on the Chemical Modification of Lignin: Acetylation versus Silylation

Abstract

Soda lignin was functionalized with tert-butyldimethylsilyl groups by the reaction with tert-butyldimethylsilyl chloride. The reaction conditions leading to a quantitative derivatization of lignin, hydroxyl groups were determined by 31 P and 1 H NMR and compared with those of acetylation. The functionalization was also confirmed by FTIR and size exclusion chromatography. The silylation enhances the thermal stability and lowers the T g of lignin as compared to the acetylation. In addition, the silylated lignins are soluble in a wider range of organic solvents, including solvents of low polarity and show a clear hydrophobic character with a contact angle with water higher than 100°. Neat, acetylated, and silylated lignins were then blended with low density polyethylene, and injection molded materials were analyzed with tensile tests, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). This study reveals the higher compatibility of the silylated lignin with the polyolefin matrix and hence the great potential of the silylated lignin for a use as an additive in apolar polymer matrices.

Natural Polymers from Biomass Resources as Feedstocks for Thermoplastic Materials

“…Although pure lignin derivatives were not processed alone, thermoplastic blends with PE were prepared. Material characterization revealed higher compatibility of silylated lignin compared to neat and acetylated samples …”

“…Material characterization revealed higher compatibility of silylated lignin compared to neat and acetylated samples. [100] With regard to etherification, both hydroxyalkylation and methylation, focusing on a reaction with the phenolic hydroxy groups, have been performed. [95] Hydroxyalkyl derivatives can be obtained by treatment with an alkylene oxide such as ethylene, butylene or propylene oxide in solution.…”

A Bio‐Based Allylphenol (Eugenol)‐Functionalized Fluorinated Maleimide with Low Dielectric Constant and Low Water Uptake

“…After removal of the solvent under reduced pressure, the residue was purified by column chromatography on silica gel using a mixture of hexane and dichloromethane as the eluent to afford a white solid in a yield of 83%. 1…”

“…Recently, there has been an increasing interest in the investigation on the biomass having aromatic skeletons due to its rigid chemical structure that can endow the materials with high thermostability. [1][2][3][4][5] The renewability and remarkable abundance of biomass have seen interest from the researchers in both academia and industry. Therefore, bio-based chemicals have been considered as the most promising candidate for polymer precursor.…”

Surface modification of lignin for applications in polypropylene blends

“…14 Attempts to use modified lignin itself as a biobased coupling agent for polyolefin composites have also been reported. [14][15][16][17] More recently, a study done by Buono et al 18 on the silylation and acetylation of soda lignin showed enhanced hydrophobicity, thermal stability, and better compatibility in silylated lignin compared to neat or Additional Supporting Information may be found in the online version of this article. acetylated ones when it was blended with low-density polyethylene.…”