Transforming Cellulose Processing

Cellulose Processing, University of Leeds, Mike Ries

Cellulose is the most common organic compound on Earth, about 33% of all plant matter is cellulose. For example, the cellulose content of cotton is 90% and that of wood is 40–50%. For industrial use, cellulose is mainly obtained from wood pulp and cotton and converted to a wide variety of products including compostable packaging (eg crisp packets), processed as films to provide gas and moisture barriers (eg cellophane) or utilised as an energy crop for biofuels. More recently, scientists have begun to explore cellulose as a component for prototype electricity-storage devices (eg batteries), biodegradable nappies and bioplastics as well as develop a plethora of end-user applications including specialty fibres for the automotive industry, medical devices and pharmaceuticals.

Processing of cellulose, however, is either highly polluting or energy consuming. Therefore, to exploit cellulose as a source of continued and accelerated innovation, leading to commercialisation, industry is focused towards cleaner, cheaper and superior cellulose processing routes. Fundamental polymer physics research translated towards greener cellulose process routes is therefore placed to have a huge impact on several major research themes and end-user applications across health, food, agriculture and biotechnology, energy as well as new materials and production technologies. In this respect, the outcomes of this research proposal can be considered a “platform or enabling” knowledge.

Our idea is to use ionic liquids combined with cosolvents as new green cellulose solvents for cellulose processing. An ionic liquid (IL) is a salt that is liquid at ambient temperatures and a cosolvent is a fluid that is miscible with an IL. Our research will have a far reaching impact as it will enable companies making man-made cellulose fibres or derivatives to introduce step-change innovations towards greener, cheaper and superior cellulose processing routes. This has direct relevance to a wide range of end-user applications and the development of new recyclable high performance materials. This includes: speciality fibres for the automotive industry (injection moulding composites); hygiene products (skincare, absorbents, disinfectant wipes) and medical applications (dressings, swabs, gowns); food formulations and pharmaceuticals (tablets, coatings).

Presently there are only a handful of articles in the literature concerning the solution properties of cellulose-IL blends. There is only one publication in the literature on cellulose processing from an IL and that is by us. There are only two publications on the use of cosolvents in conjunction with ILs to dissolve cellulose and these do not concern processing. Almost nothing is known about the interactions between the components (cosolvent, IL, cellulose) in these systems. Therefore there is much to learn about these systems which makes them academically highly interesting and this combined with the industrial relevance motivates our work.

A novel aspect to this research is the study of cellulose coagulation using Magnetic Resonance Imaging (MRI) techniques. There are only two publications that have previously attempted this showing it to be possible, and it has never been carried out for an IL. MRI will allow us to track the phase separation of the polymer, giving molecular concentration and dynamics information, enabling us to test different theories for phase separation.

Centre de Mise en Forme des Materiaux (CEMEF)Innovia Films

This translational research will be underpinned through a collaborative partnership linking Innovia Films, UK – world leading producer of cellophane films, University of Leeds and Centre de Mise en Forme des Materiaux (CEMEF), France – an acknowledged world leader in biopolymer materials. Both CEMEF and Innovia Films will allow use of their facilities at no cost to this proposal and further to this Innovia Films will fund it with a £40k contribution. This project supports the direction that Innovia Films is taking by translating fundamental polymer physics research into an optimised processing method. Embedding our academic knowledge into an advanced manufacturing context will offer key step change advantages, transforming.

For more information please contact Dr Mike Ries