The industrial sector is experiencing a time of great effervescence in terms of materials, with candidates called to mark a before and after, such as graphene or carbon nanotubes, on which high expectations have been placed. Perhaps less well known, but equally very promising for certain applications, is nanocellulose.
There are several typologies, although the majority is from the cellulose fibers present in the woody part of plants, composed of cellulose fibers, lignin (a natural glue) and hemicelluloses (sugars). «The wood is chopped up; it is thrown into a reactor with water and chemical reagents that dissolve the lignin; it goes away with the water and the cellulose fibers that were in the wood are released “, he explains. Álvaro Tejado, Principal Investigator at Tecnalia in charge of the cellulose and nanocellulose technology line. These fibers are in turn made up of millions of cellulose nanofibers, which are the ones in charge of extracting and valuing in the Tecnalia nanocellulose laboratory, located in Azpeitia (Guipúzcoa), to which state-of-the-art technologies have been incorporated to make it a semi-pilot scale plant for the production of cellulose micro / nanofibers, with an automated feeding system, unique in Spain.
«We have been working with the masuko, a kind of ultrafine mill, because it allows us large productions. We are very oriented to the industry, to transfer the potential of nanofibers to the products of companies and we needed to produce kilos, “he says.
This supermaterial has a multitude of applications in different stages of development. One of those that is closer to the market is the ‘packaging’, due to the race to replace petroleum-derived plastics. «Because of its small size, it closes the pores and acts as a barrier against oxygen, so that the food lasts longer. The current films work very well, but we have to look for sustainable, biodegradable and compostable alternatives », Tejado emphasizes.
In traditional sectors such as paper it can also be useful. «As the papers are already good properties for the market to which they go, it is helping companies to lower the cost of production. They use less cellulose fibers, relatively expensive, and they put a lot of filler (pigments, for example), very cheap, thanks to the nanofibers they introduce, “he says.
Another of the niches where it has a future, although more in the long term, is that of cement due to its ability to modify the rheology (viscosity) of a mixture. “Cellulose nanofibers in a very low concentration, less than 1%, can make it more or less viscous depending on interest,” he says. This property could benefit sectors such as paint, varnishes, adhesives … a universe of possibilities to which Spain needs to react. “The Scandinavian countries have invested and invest a lot in R&D because they have seen great potential in terms of their own resources. Spain is in the leading group in Europe for forest resources, but it is necessary to invest in it, support the creation of companies, own technology, etc. Here we are in the queue in that part, trying to convince everyone that this is an opportunity for the country, “he laments.