Chemical Modification of Cellulose Fibres Using Fluorine Promoted Esterification (FPE) Chemistry via Carbonyldiimidazole (CDI)

There is an increasing demand for sustainable materials derived from renewable resources due to the environmental concerns in our society. Cellulose is one of the promising materials as it is the most abundant natural polymer possessing very intriguing properties. These are associated to its high aspect ratio, excellent mechanical properties and large number of reactive groups available for further functionalization. Over the past decades, a substantial amount of research has focused on extracting cellulose nanofibrils (CNFs) from cellulose fibres and using CNFs in various applications and industries. However, utilising the cellulose fibrils inside the microscopic, porous cellulose fibres directly without converting them to its fibrillated form is still in its infancy.<br/>In this work, we investigate the chemical modification of fibres by means of reactive probes that penetrate throughout the entire fibre wall despite the limited pore size in the fibre network. Reactive probes are synthesised via CDI activation, using Cesium fluoride as the key catalyst to ensure robust, efficient, scalable as well as sustainable esterification. As a result, a unified synthetic strategy is explored for functionalising cellulose fibres with various functional groups that will elevate fibre capabilities without expensive and energy demanding fibrillation and a much more convenient processing due to the microscopic dimensions of the cellulose-rich fibres.