Structural characteristics of industrial lignins in respect to their valorization

The effect of raw material and pretreatment procedure on the structure and properties of industrial lignins was evaluated by detailed chemical and physical characterization. The application potential of studied lignins was considered based on those. Hydrolysis lignin and steam exploded lignins had clearly distinct characteristics compared to the spent liquor lignins; higher molar mass, significantly higher amount of native aryl ether linkages and thereby low phenol content. The hydrolysis lignin also contained significant amount of carbohydrate and protein residues, which may affect the applicability. For resin applications, the kraft lignins seem most reactive in respect of high phenol content. The high molar mass of hydrolysis lignin and steam exploded lignins could be beneficial for dispersants and composites