Since around year 2000, there has been a notable increase in the number of patent applications filed regarding new MFC materials, new processes for production and new application areas for MFC. The nomenclature used in the field of MFC varies (nanocellulose, cellulose nanofibers, nanocellulosic fibers etc). In this blog post, I will give you a summary of a few interesting patent applications recently published, using the “original” nomenclature MicroFibrillated Cellulose (MFC).
Why not use MFC to dye fabrics and textiles?
Scientists at the University of Georgia Research Foundation Inc and Clemson University has filed a patent application on textile dying using MFC (described in the patent application as nanocellulosic fibers, US2016/0010275 A1). The invention is based on the use of MFC to dye fabrics and yarns like cotton or polyester and thereby reducing or eliminating the need to use water in the dying process.
This will lead to reduced waste water effluents and energy consumption. MFC has a very high surface area with many available OH groups on the surface of the microfibrils. This enables it to interact both with the dye molecules and the fibers in the yarn or fabric. The MFC can thereby act both as a carrier for the dye chemicals and as a binding agent to adhere to fibers in the textile materials. The large surface area of MFC also leads to a better absorption of the dye molecules. The textiles dyed with MFC is described as showing a good rubbing resistance and crocking (rub-off of color) resistance.
The inventors claim that the amount of energy required to dye and dry textiles using MFC is a fraction of that required for conventional dying, and that the water consumption is expected to be reduced with more than 80%. It is also stated that “nanocellulose-based dyeing procedures reduce water and energy consumption while improving the textile product performance”.
Something to consider if you are in the textile or fabric dying business?
Or in a filtration media?
The high surface area of MFC makes the material a promising candidate for use in filtration medias. For example, at the Research Foundation for the State University of New York, they have looked at using MFC in membranes for gas filtration (WO2015187412 A1).
The membranes have high filtration efficiency, high retention and a low pressure drop. They can be used to filter, for example air, to remove airborne bacteria/viruses, harmful particles/dust, toxic gasses etc. In one example they have used crosslinked oxidized MFC to create the filtration membrane.
Dailian University of Technology in China have a patent application on the use of a blend of cellulose diacetate and MFC to make an ultrafiltration membrane (CN 105107390 A). The membrane has the advantages of both the MFC and the cellulose diacetate, and has a high porosity, large pore diameter, high hydrophilicity, high flux, good contamination resistance and good mechanical strength.
Or, perhaps, to improve cement-based materials?
MFC has, as mentioned, a high surface area with many available hydroxyl groups on the surface of the microfibrils, giving the material a high water holding capacity. In addition, MFC has high crystallinity and a high aspect ratio, giving the material high strength.
These are all properties that could be useful in cement-based materials. For example, Nanjing Forestry University in China have published a patent application on use of MFC to reinforce cement-based materials (CN 105174768 A). They claim that the MFC improves the degree of hydration, reduces the porosity and increases the flexural and compressive strength of the cement.