Self-assembly of kraft lignin-acrylamide polymers

Abstract

Lignin has been produced in large quantities in the pulp manufacturing process; however, its valorization has been challenging. The production of lignin polymers has shown pathways to produce water soluble products to be used as flocculants and dispersants. However, these lignin-based polymers may interact with each other and form large flocs that could reduce their efficiency in interacting with other colloidal particles. This study aims at evaluating the self-assembly of kraft lignin-acrylamide polymers in aqueous environments under different salt concentrations. The sedimentation studies using a vertical scan analyzer showed that a higher molecular weight lignin polymer had a higher tendency for sedimentation than a lower molecular weight one. Quartz crystal microbalance with dissipation (QCM-D) was used for studying the self-assembly behavior of lignin polymers with different molecular weights. The results suggested that lignin polymer with the higher molecular weight of 96,992 g/mol had a higher tendency to self-assemble by forming a loose floc as compared to that with a lower molecular weight. Also, salt disrupted the self-assembly of lignin polymers greatly.