Cellulose nanofibrils (CNFs) can replace oil-based materials, add functionality, and generate completely new materials and products. However, low consistency of traditional CNFs has constrained some of their potential applications. High consistency nanocellulose helps to clear out these obstacles.
Development of novel bio-based nanomaterials is strongly on FinnCERES’s agenda. VTT has developed and patented a novel technology for producing nanocellulose from plant-based cellulosic materials, such as wood-based pulps and agro-based residues. This technology – called High-consistency Enzymatic Fibrillation of Cellulose (HefCel) – relies on enzymes and uses much less mechanical energy than the manufacturing of traditional CNFs. The process is simple and can utilize existing industrial equipment. It has proven to be energy efficient and cost-effective as well.
The greatest advantage of HefCel is its high consistency. Traditional CNF’s struggle with low consistency and can only offer a dry matter content of approximately 5%. This is a challenge in many application areas. Dewatering is not a solution either, due to the high water holding capacity and gelation of traditional CNFs. Drying also presents a problem, due to aggregation of fibrils and difficulties in re-dispersing the once-dried material. HefCel nanocellulose offers a good alternative: it can reach a dry matter content of 25%.
From paints and coatings to fire retardants and packaging
HefCel is suitable for applications that need low water content, such as paints and coatings or composites. It is easy to handle and dewater. Unlike the traditional CNFs, HefCel does not tend to gelate at low consistency, and it can be applied to other materials with high dry matter content, with no need for dilution.
One widely investigated application for HefCel is fire resistant coating. Together with pigment, HefCel forms a barrier film that reduces the access of oxygen to the surface and inhibits combustion. This fire retardant can be sprayed directly on the materials, which is not possible with traditional CNF’s.
HefCel can also be used as a barrier for oxygen and grease in packaging materials, or to strengthen cardboard, veneer or polymeric composites – although there are some compatibility issues with the latter. When HefCel dries out, it creates a strong glue. This could offer an alternative to fossil-based glues, especially for wood-based materials.
In FinnCERES, HefCel has been used as a carried material for colloidal lignin particles possessing antimicrobial properties. By combining these two unique materials, novel antimicrobial coatings can be manufactured.
All in all, HefCel can be used for improving materials and creating new ones, just like other CNFs. The main difference is the easy use, especially in application areas that suffer from the excess of water.
Call for brave initiatives
Extensive research on HefCel has taken us far, and VTT is prepared for small scale production of HefCel. Technoeconomic calculations have been done to understand the cost structure and to be able to discuss pricing. For a specialty chemical, HefCel offers competitive pricing.
Now, it is time to move on towards upscaling the production and commercializing HefCel. HefCel has great potential for replacing fossil materials and for creating high value products within the forest industry. These possibilities must be considered and discussed further with daring and open mind. FinnCERES is eager to find visionary partners that aim to bring innovative nanocellulose products to the market and are ready to take the next steps together.
Heli Kangas
Technology Manager, VTT
