Structural and Compositional Characteristics of Technical Lignin Derived From Non‐Wood Biomass: Bagasse and Kash

Lignin is one of the available biopolymers on earth, so it can play a vital role in moving toward a bio‐based society. In this paper, lignin derived from non‐wood sources like bagasse and kash was characterized in order to facilitate its valorization. Lignin obtained from the soda liquor was considered as technical lignin, and it was compared with the acidic dioxane‐extracted lignin from the corresponding non‐wood. The isolated lignins were characterized using elemental analysis, methoxyl content determination, molecular weight distribution, FT‐IR spectroscopy, and advanced NMR techniques (quantitative 31 P and 2D HSQC). The methoxyl groups per C 9 unit in dioxane lignin from bagasse were 1.20, which was slightly higher than that of kash dioxane lignin (1.16/C 9 ). Technical lignins showed comparable or slightly lower methoxyl content per C 9 unit. The weight‐average molecular weight (Mw) of technical lignin was lower than that of corresponding dioxane lignin. The phenolic hydroxyl groups in technical lignin were higher than those of corresponding dioxane lignin, as observed from 31 P NMR analysis. Furthermore, 2D HSQC NMR analysis showed that both lignins were primarily composed of syringyl (S) and guaiacyl (G) units, with the S‐unit type being dominant. These findings provide valuable information on the structural and chemical properties of non‐wood lignins, supporting their potential utilization in bio‐based applications.