1. Processing of cellulose-rich organosolv fractions for functionalization and valorization of potential biobased materials.
With the increasing demand of packaging material, it becomes necessary to look for bio-based alternatives to replace fossil-based products. One such product is foam, which today is predominantly made from expanded polystyrene and used majorly in packaging applications. These foams are difficult to recycle as they mainly contain air and thus ends up in the landfills and a part in the nature. Nonetheless, Cellulose foams can be created as bio-based alternatives. However, cellulose shows high affinity towards water and thus it becomes imperative to modify it to make it hydrophobic. Enzyme modification is a sustainable technique to graft functional molecules onto the cellulose surface making it hydrophobic. One such enzyme called Laccase has shown promising results in improving its hydrophobicity by facilitating the grafting of phenolic compounds. A similar approach is planned for this study to produce hydrophobized organosolv pulp assisted by Laccase. The modified fibers can be used to make a variety of bio-based materials such as foams. In the preliminary part of this doctoral thesis work, to create biodegradable cellulose foams, organosolv pulps were tested and compared to Kraft pulp to study the effect of fiber characteristics that directly impact the physical structure of foams. Usually, air is induced into the fiber-solvent system to give a porous structure to the foam. This phenomenon is thermodynamically unstable and requires external agents, such as surfactants or particles. It can also lead to the hydrophobic moieties grafted onto the cellulose surface to act as stabilizing particles for the foams.