Energy-efficient method or producing nanocellulose

Professor Akira Isogai, Associate Professor Tsuguyuki Saito and Dr Yoshiharu Nishiyama will be awarded the 2015 Marcus Wallenberg Prize.

A group of researchers from Japan and France is being awarded The 2015 Marcus Wallenberg Prize for their development of an energy-efficient method to produce nanofibrillated cellulose. The prize-winners will receive their diploma from the hands of His Majesty the King of Sweden at a ceremony in Stockholm, Sweden, on Monday 28 September 2015.

Nanofibrillated cellulose has great potentials. This nanoscale material has a surface area and shape that enables the formation of strong networks. The manufacturing process where the wood pulp is mechanically broken down to its nanoscale building blocks is however very energy-intensive, which has hampered industrial interest so far.

Professor Akira Isogai, Associate Professor Tsuguyuki Saito from the University of Tokyo and Dr Yoshiharu Nishiyama from the Centre de recherches sur les macromolécules végétales, Cermav in Grenoble, France, have found and developed an energy-efficient way to produce nanofibrillated cellulose. Their discovery on using a specific oxidation reaction as a tool to open up the wood material prior to mechanical disintegration has reduced the energy demand dramatically. The three scientists are awarded the 2015 Marcus Wallenberg Prize of SEK 2 million for this groundbreaking discovery. Stabilizers in chemicals, food and cosmetics, raw materials for new types of textile fibres or composites or materials for wound dressing are just a few examples of the wide field of possible applications.

– The work of the prize-winners has stimulated more intensive research on nanofibrillated cellulose and its applications around the world, says Professor Johanna Buchert from Natural Resources Institute Finland. She is also a member of the Prize Selection Committee of the Marcus Wallenberg Foundation.

The generalized term nanocellulose refers to both nanofibrillated celluloses and cellulose nanocrystals. They have similar chemical compositions but different properties such as size and crystallinity. Nanofibrillated cellulose consists of longer fibrils and is more flexible than nanocrystalline cellulose.

Nanocrystalline cellulose is obtained by chemical removal of the amorphous parts of the fibre. The 2013 Marcus Wallenberg Prize was awarded Professor Derek Gray, McGill University, Canada, for his research within this field.

Nanofibrillated cellulose on the other hand is produced from wood pulp by mechanical treatment. In addition to the crystalline regions it also contains parts of the amorphous regions. Depending on the process the fibres can either become organized in bundles of fibrils or isolated in long and spaghetti-like fibrils.

Nanofibrillated cellulose has become more interesting for various applications since the Marcus Wallenberg Prize-winners Akira Isogai, Tsuguyuki Saito and Yoshiharu Nishiyama were able to exploit the specific oxidation reaction as a tool to facilitate the mechanical disintegration of the wood pulp. By their method the energy need can be reduced from 30 000 kWh/ton to 100-500 kWh/ton. The cellulose produced this way is even more homogeneous.

- It is a significant discovery that paves the way for nanocellulose being one key product of the future forest industry. The energy consumption is a very important parameter, and the traditional production of nanofibrillated cellulose has been too energy-intensive to attract industrial interest, says Johanna Buchert.

The combination of crystals and the flexibility of the fibrillar structure gives nanofibrillated cellulose the potential of forming barriers, retaining large amounts of water, being able to modify rheological properties of liquids or display highly porous light structures as dry.

Its strength and lightness is valuable for making reinforced composites, improved paper grades and textile fibres, while the water retention ability and viscosity is useful for producing stabilizers in food, cosmetics, paints and adhesives or even in pharmaceutical products.

- We must find new products from our forest raw material to renew the forest industry. This years' prize has opened up a new pathway and created a new route of opportunities.