The bio-feedstock of tomorrow for controlled and reversible chemical modification on the macro and microfiber level 

Itaconic acid, a di-carboxylic acid produced from citric acid or fermentation of sugars, is predicted to become a valuable bio-based chemical for the future, making it interesting for applications in cellulose based functional materials. This project will investigate the tailored modification of Bleached Kraft Pulp (BKP) with itaconic derivatives. Since the reactivity to a large extend depends on water-fibril interactions it is paramount in the development of modification methodologies to understand how water interact with fibres in microfibril bundles and close to the fibril surface, so called confined volumes.  To gain insight on the weak hydrogen network and how it affects fibril surface behaviour and properties we will further develop our THz-Platform and introduce dielectric spectroscopy, two techniques hardly used in cellulose characterization but that are highly sensitive for weak hydrogen bonds and water dynamics. Central key research questions are: How do reactions and mixing conditions affect water interaction and correlate to modification on the macro and microfiber level? Are additives needed to promote chemical modification? With the new insights on the microfibril level of cellulose and how it interacts with water we envisage to develop a platform of functional fibres and fibrils with new properties, targeting hydrophobic fibres and flexible fibrils with high durability that are recyclable.  Bringing the knowledge to the next level is to define and introduce multiscale descriptors for modified fibrils will make it possible to correlate molecular details with fibril properties.
Extension of the project is conjugation of Azetidinium salts to the itaconic-BKP. Azetidinium salts is the reactive part of polyamidoamine-epichlorohydrin (PAE) wet-strength resins.