Soft highly swelling fibres by alkali-activated chemical modification 

To make cellulose fibres more flexible and malleable, components inside the fibre must be properly modified, that is, the lignin, hemicellulose or cellulose needs to be at least partly transformed into a proper derivative. Several cellulose derivatives are today produced through chemical reactions that involves formation of ether bonds. To reach sufficient efficiency, these reactions are commonly performed in alkaline medium. One such typical modification is to react glycidyltrimethylammonium chloride, an epoxide reagent commercially used to produce cationic starch, with alkali-activated hydroxyl groups in the cellulose backbone, resulting in highly swollen fibres carrying a net cationic charge. Highly swollen fibres are known to, at least under aqueous conditions, easily fibrillate into cellulose nanofibrils when subjected to mechanical shear. However, the dry properties of these fibres, and in particular their thermomechanical properties, have not been studied in greater detail. Therefore, this project will fundamentally study the importance and influence of using alkaline activation of cellulose before derivatisation, and to study structure–property relationships by using a set of different fibres. In the event that glycidyltrimethylammonium chloride does not provide thermoplastic fibres, there are many other reagents that might provide this property, as well as other properties, through the use of similar chemistries, highlighting the fundamental importance and general relevance of this study.