The chemical modification of lignins with succinic anhydride in aqueous systems

Chemical modification of oil palm trunk fibre lignin, poplar lignin, maize stem lignin, and barley, wheat, and rye straw lignins was achieved by esterification with succinic anhydride in aqueous solutions. FT–IR spectroscopy clearly revealed the differences in the structure of the modified lignins as a result of this succinoylation. These changes were reflected by thermal analyses such as thermogravimetric analysis and differential scanning calorimetry. All the succinylated lignin preparations showed an increased thermal stability compared to the corresponding unmodified lignins.