Nanocellulose: A Disruptive Technology Ahead of its Time
By Rosemarie Szostak, Ph.D., Nerac Analyst
Originally Published July 23, 2014
Nanocellulose is making waves as a viable alternative to the more expensive high tech materials such as carbon fibers and carbon nanotubes. Its first creation in 1977 was inauspicious and likely accidental. A researcher at a pulp and paper mill asked the question “What would happen if I took some wood pulp and put it into a milk homogenizer?” At 80°C and 8,000 psi he turned his wood pulp slurry into a firm translucent gel. Not sure of the value of the discovery of this early nanocellulose, the company opened up the technology to anyone who wished to exploit it. Nanocellulose progress lay effectively dormant until a decreasing paper demand sparked new interest in this pulp product as a viable new market entry.
Nanocellulose research today is at the brink of penetrating many market sectors. Some are listed below.
- films and barriers
What is Nanocellulose?
Cellulose is the most abundant, natural, renewable and biodegradable polymer that occurs as a nanostructure in plants. It is made up of bundles of long chain polymers of sugar bound together through hydrogen bonds.
If one looks closely, within the wood these polymer bundles contain a mix of crystalline and amorphous phases. The crystalline phase is composed of nano-diameter 10-100 nm rods and from 100 nm to 100 microns in length. Though originally produced using high pressure, this crystalline phase can also be isolated through acid extraction of pulp. There are two nanocellulose materials that have been extracted from trees and plants. Though the nomenclature has not yet been standardized, they are usually referred to as nanocrystalline cellulose (NCC) and micro/nanofibrillar cellulose (MFC/NFC). A third nanocellulose material, made from bacteria, is called bacterial cellulose (BC).
What is So Exciting About Nanocrystalline Cellulose?
When working at the nano-scale, the surface properties always trump bulk properties. This means that the huge surface area and strong hydrogen bonding characteristics based on the –OH groups on the sugar chains in nanocrystalline cellulose can potentially impart unique characteristics not achievable by ordinary wood pulp or petrochemical-based nano-range crystalline polymeric materials. Researchers have found that nanocellulose is very stiff, lightweight, has an order of magnitude greater than the tensile strength of steel, can be highly adsorbent, and when made into a film is gas impermeable. Nanocrystalline cellulose can be produced far more cheaply than other nano-phase materials.
Why the Interest in Nanocrystalline Cellulose?
Papermaking is an ancient industry with millennia of success. Technological advances at the end of the 20th century with the adoption of computers and the Internet have decreased the demand for newsprint and hence represent a long term threat to the pulp and paper industry. The forest-products industry, a $260 billion sector in the US economy, recognized the need to explore new products that can substitute for the declining newsprint demand. Nanocellulose offers the potential for such a value-added high performance product line. Tappi, the non-profit pulp and paper association, has been working with the pulp and paper industry and governments around the world to accelerate the development to bring this material to market.
Commercial Production or Still a Pipe Dream?
The answer to this question is that it is getting close. Projections initially showed that nanocellulose was destined for a steady growth, but market watchers are rapidly changing their assessments as more demonstration projects came on line with a marked increase in capacity. Present predictions are for a capacity of 800 tonnes/year by 2017 but that is subject to significant revision as more and more facilities come online. The early players in commercializing the material include (projected rates for 2013-2014):
- FPInnovations (pilot plant with capacity of 10 kg/week).
- The U.S. Forest Service’s Forest Products Laboratory (pilot plant capacity of 35-50 kg/day). Collaboration with University of Maine, a demonstration plant with capacity 500kg/day.
- Alberta Innovates (pilot plant capacity of 100 kg/week)
- BioVision Technologies (pilot plant capacity of 4 ton/year)
- Celluforce Inc. (demonstration plant capacity of 1 ton/day)
- Inventia (demonstration plant capacity of 100 kg/day).
Nanocrystalline Cellulose Applications
A good way to identify some of the potential uses is through patent activity. Examining patent activity over the last two years, a number of companies have started looking at nanocellulose for a variety of applications. A few of the innovations are highlighted below.
- Samsung is looking at nano-structured cellulose for liquid crystal displays (LCD).
- Konica Minolta is exploring its use in optical films.
- BC Genesis, a biotechnology firm, is developing these materials for building blocks in surgical sutures and reinforcing and promoting regeneration of damaged tissue or implants.
- Toppan Printing is developing this material as a water resistant film.
- Kao Corporation is investigating these materials for cleaning applications.
Other patent applications include the use of nanocrystalline or fibril celluloses in composite and foam articles, scaffolds for tissue engineering, waterproof and grease resistant protective coatings, fuel cell electrodes replacing carbon paper, antimicrobial material support, cement enhancements, spun fibers to replace Kevlar, membranes, and filters.
Exploring New Nanocellulose Applications
The potential low cost of this material, low toxicity, and the ability to custom tailor the surface (anionic, cationic, hydrophobic, addition of other functionality) by utilizing the chemistry of the –OH groups on the cellulose offers unlimited possibilities. The present state of applications for nanocellulose has been limited by the availability of material to explore. This is changing as more and more manufacturers move from pilot to demonstration to full commercial plants.
If you are interested in evaluating nanocellulose for applications of interest or to improve material properties beyond what your present technology can achieve, nanocellulose materials (crystalline and fibril) are provided by the companies listed in the earlier section. Other suppliers include Asahi Kasei, Borregaard, DaiCel, Nippon Paper, Stora Enso, UPM-Kymmene, and Verso Paper.
Prospects for Tomorrow
It is not often that a new basic material enters the market that can have a combination of ‘green’, low cost and exhibit properties that, right off the shelf, have the potential to improve a host of products. To find a material that also can undergo classic textbook chemistry reactions (sugar chemistry) to modify or tailor the surface properties for further enhancement of its material properties or even impart properties not previously available, should excite the minds of product innovators around the world.