Embrapa Instrumentation (São Carlos, SP) and Bio Nano company researchers have started to test the production of cellulose nanocrystals (CNC) on an industrial scale. From the manipulation of macromolecules, scientists have created the basis to develop it from plant fibers such as cotton and eucalyptus. Now they want to scale up production and speed the process up in a cost-effective manner. Similar to rice or long-grain rice, but about 200,000 times less thick, nanocrystals fit the concept of so-called green materials, since they come from renewable and sustainable sources. Research carried out by Embrapa - which has worked to obtain this product since 2007 - shows that they can be extracted from lignocellulosic fibers from sugarcane bagasse, coconut shells, rice shells, cotton, eucalyptus, among others, and even from residues such as reforestation wood discarded by the industry. As hard as steel ”The importance of extracting nanocrystals of cellulose is to obtain a very resistant natural material, which is as hard as steel and also can be added into other materials, changing their mechanical properties," explains Embrapa researcher José Manoel Marconcini. CNC characteristics have attracted industries around the world. Nanocrystals can also incorporate physical, chemical and biological properties and are beginning to be employed in several areas (see table below). However, there are bigger challenges for its wider utilization: high cost, low productivity, long production time and still little material available in the market. Given the material’s potential, Bio Nano combined its expertise with Embrapa Instrumentation's Nanotechnology Laboratory for Agribusiness (LNNA), infrastructure to extract cellulose nanocrystals on a pilot-scale. Various applications Cellulose nanocrystals are advantageous: they present high mechanical properties, low density, high crystallinity, lightness, biodegradability and biocompatibility. Its application extends from the medical area to agribusiness, in which they can be employed in the production of fertilizers and pesticides aiming at increasing efficiency, using smaller quantities in the same area. “It is important to remember that in order to have these properties it is necessary that the CNCs are well dispersed and homogeneous in the product. Thus, few amounts (about 1%) are sufficient for major improvements,” says Bio Nano materials engineer Ana Carolina Bibbo. Nanocrystals have been used in polymeric matrices, in oil and gas industry sensors, in special dressings and prosthetics, in paints, coatings, cosmetics and, with the addition of other substances, in the electronics industry. They can also be coated with water-soluble polymers to inhibit nanocrystals agglomeration, and subsequently used to cover the surface of paper sheets to improve surface properties (such as a smoother, more uniform gloss and texture) and increase mechanical resistance. Grams to kilos The company's goal is to increase production by 20 times and move from the current 50 grams obtained experimentally in LNNA to kilograms in the industrial process. The proposal is to shorten the extraction time of the material from 20 days to just one day. On a laboratory scale, the cellulose nanocrystals were obtained from cotton, sisal, curauá, macaw palm, gravatá, sugarcane bagasse, oil palm residue and eucalyptus pulp. At the industrial pilot-scale stage, the production will involve either eucalyptus fibers bleached by the kraft process or cellulose pulp due to its availability in large volumes. To enable the full-scale tests, Bio Nano materials engineer Ana Carolina Correa Bibbo sought support from development agencies. The project was conceived by the Small Business Innovation Research Program (PIPE) of the São Paulo state Research Support Foundation (Fapesp). “New materials with distinct performance and Brazilian CNC products may be the impact of this project, adding value with renewable sources of raw material in agribusiness in Brazil, as well as generating jobs and income,” says the expert, who had Embrapa researchers Luiz Henrique Capparelli Mattoso and José Manoel Marconcini during her PhD at the Federal University of São Carlos (UFSCar). Promising market for cellulose The use of cellulose nanocrystals has attracted the interest of several countries. Canada, Finland and the United States have been heavily investing in the area. The new product can replace current raw materials for new product development. Estimates indicate that the nanocellulose crystals could be 20 times more expensive than cellulose. The US Market Research Store estimates that the nanocellulose market was worth US$65 million in 2015. The company estimates that this amount will rise to US$ 530 million in 2021, an increase of 30% per year. Brazil is one of the world's largest producer of cellulose. With scientific investments in the area, nanocellulose is a great apportunity to enhance the commodity value create new business in Brazil. A format for each use On a nanometric scale, cellulose has two shapes, nanofibrils and cellulose nanocrystals. Nanofibrils (CNF) are spaghetti-shaped, easily intertwined and more suitable for reinforcing plastic packaging or added as thickeners. The cellulose nanocrystals are similar to rice in appearance and are considered a nobler material because they have high crystallinity and mechanical resistance, with a theoretical elastic modulus that is similar to that of steel. According to the researcher, they can have an electrical charge on the surface, be insoluble in water and in most organic solvents, and still have excellent optical and electronic properties due to their dimensions. They measure 5 to 20 nanometers (nm) wide and 100 to 500 nm long. Cellulose nanocrystals can be used for various applications, such as making special papers and modifying paper surfaces; in polymeric nanocomposites; in cosmetics; as mechanical reinforcements in paints, and many more. Translation: Emanuelle Galdino, supervised by Mariana Medeiros