Multifunctional fibres for different end-use applications

During the last decade there has been a large focus on using wood-based fibres in new materials and there has also been an overwhelming development of the use of nanocelluloses (NCs) in new types of composites where the properties of the Cellulose NanoFibrils (CNFs) or Cellulose NanoCrystals (CNCs) are utilized to create unique material properties. During these developments there has been a concomitant, fantastic development of fibre and NC modifications to alter the properties of the cellulose rich materials to meet certain end-use properties. Among these, the oxidation using periodate followed by different post treatments can result in fibres that have excellent stress/strain properties and which can be very useful in creating interesting fibre and fibre network properties. It has also been shown that the use of a Layer-by-Layer treatment of the fibres using special polyelectrolytes of opposite charge is a useful technique to totally alter the mechanical properties if networks prepared by using the treated fibres. Very recently it has also been shown that a post treatment of composites of CNF and alginate with Ca2+ is able to induce a huge improvement in the mechanical properties of the NC/alginate networks.

All these different modification techniques can naturally be applied to ordinary cellulose-rich fibres. Traditionally this is preferably performed in close connection to their final application, to modify fibre properties to meet certain end-use properties. This means that the supplier of cellulose rich fibres has basically no control of how the fibres should be optimized in different applications despite their deep knowledge about fibre properties and the possibilities with different types of modifications. A very interesting alternative to this traditional approach is to pre-treat the fibres to fit certain end-use properties and to allow for a converting of the fibrous network to a final product before triggering the built-in fibre functionality. This would allow for creating an added value to the fibres and also to allow for the development of totally new fibre-based products.