Nanocellulose powder developed
9 Dec 2011 by Evoluted New Media
Nanocellulose has the potential to be used in medical technology and the food and pharmaceutical industries, but when it dries out, it loses some of the mechanical properties that make it so valuable. Now researchers from EMPA have developed a manufacturing process for nanocellulose powder – the raw material for creating nanocomposites. It could find uses in lightweight structures for the car industry, or as a membrane and filter material for biomedical applications.
Nanocellulose fibres are several micrometres long, but only a few nanometres thick, and are closely interlinked. Their extremely large surface area makes them ideal for chemical-physical reactions with water, organic and inorganic chemicals and polymer compounds.
However, they need to be extracted in a water-based suspension and when the material dries out the cellulose fibres stick and clump together. Researchers from the Wood Laboratory isolated nanocellulose fibres from wood pulp and developed a process to dry them without clumping and becoming rough.
The method prevents cellulose from forming clumps and sticking together, and once re-dispersed in water, the dried nanocellulose powder boasts the same properties as the un-dried, unmodified cellulose. The cellulose was treated with a technique that could easily be implemented on a large scale and is completely harmless – meaning it can be used in the food industry.
Nanocellulose powder is an attractive alternative to conventional nanocellulose suspensions for the synthesis of bio-nanocomposite materials. Suspensions currently used consist of over 90% water, which makes them expensive to transport and susceptible to degradation by bacteria and fungi. Aquatic cellulose suspensions can also be laborious to work with since during the course of chemical processing solvents must be exchanged.
Cellulose is very strong in tension and can be chemically modified to change its characteristics. When nanofibres are embedded into composites, the resulting lightweight structural materials have similar mechanical properties to steel.
