Tag Archives: nanofibrils

Cellulose aerogels for new wood-based composites

‘Frozen smoke’ or ‘solid smoke’ as it’s sometimes described, aerogel fascinates scientists.The latest on cellulose aerogels derived from wood is the focus for a February 14, 2018 Nanowerk Sportlight article by Michael Berger (Note: Links have been removed),

Aerogels, sometimes called frozen smoke, are nanoscale foams: solid materials whose sponge-like structure is riddled by pores as small as nanometers across. They can be made from different materials, for instance silicon.

Aerogels are among the lightest solid substances in the world yet flexible, extremely strong and water repellent, which makes them very interesting materials for engineers.

Cellulose aerogels, made from nanofibrils found in plants, have several unique features, one of which is super high oil absorption capacity that is several times higher than commercial sorbents available in the market.

“Encouraged from our previous work on transparent wood (“Transparent wood for functional and structural applications”; “Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance”; “Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall”), we started to develop porous wood/epoxy biocomposite materials, which preserves the original hierarchical and porous structure of wood,” Qi Zhou, an associate professor in the Department of Chemistry at KTH Royal Institute of Technology, tells Nanowerk.

“Our strategy is different from traditional wood modification methods,” explains Zhou. “It involves two steps, a simple chemical treatment to remove the lignin (delignification) at first, then back infiltration of the wood cell wall with epoxy, leaving the lumen (a void space) open. In traditional wood polymer composites, both the cell wall and cell lumen are filled with polymer.”

The scientists don’t seem to have any particular applications in mind but they are hopeful that new materials will inspire new uses. Here’s a link to and a citation for Zhou’s latest paper,

Wood Nanotechnology for Strong, Mesoporous, and Hydrophobic Biocomposites for Selective Separation of Oil/Water Mixtures by Qiliang Fu, Farhan Ansari, Qi Zhou, and Lars A. Berglund. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b00005 Publication Date (Web): February 7, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Hydrodynamic alignment and assembly of nano-fibrils results in cellulose fibers stronger than both aluminum and steel

A June 2, 2014 news item on Azonano describes the new fibres (which come from wood),

“Our filaments are stronger than both aluminium and steel per weight,” emphasizes lead author Prof. Fredrik Lundell from the Wallenberg Wood Science Center at the Royal Swedish Institute of Technology KTH in Stockholm. “The real challenge, however, is to make bio based materials with extreme stiffness that can be used in wind turbine blades, for example. With further improvements, in particular increased fibril alignment, this will be possible.”

The June 2, 2014 DESY ( one of the world’s leading accelerator centres) press release describes the research in detail,

A Swedish-German research team has successfully tested a new method for the production of ultra-strong cellulose fibres at DESY’s research light source PETRA III. The novel procedure spins extremely tough filaments from tiny cellulose fibrils by aligning them all in parallel during the production process. …

For their method, the researchers took tiny, nanometre-sized cellulose fibrils and fed them together with water through a small channel. Two additional water jets coming in perpendicular from left and right accelerate the fibril flow. “Following the acceleration, all nano fibrils align themselves more or less parallel with the flow,” explains co-author Dr. Stephan Roth from DESY, head of the experimental station P03 at PETRA III where the experiments took place. “Furthermore, salt is added to the outer streams. The salt makes the fibrils attach to each other, thereby locking the structure of the future filament.”

Finally, the wet filaments are left to dry in air where they shrink to form a strong fibre. “Drying takes a few minutes in air,” explains co-author Dr. Daniel Söderberg from KTH. “The resulting material is completely compatible with the biosphere, since the natural structure of the cellulose is maintained in the fibrils. Thus, it is biodegradable and compatible with human tissue.”

The bright X-ray light from PETRA III enabled the scientists to follow the process and check the configuration of the nano fibrils at various stages in the flow. “Research today is driven by cross-disciplanary collaborations,” underlines Söderberg. “Without the excellent competence and possibilities brought into the project by the team of DESY’s experimental station P03 this would not have been possible.”

As the scientists write, their fibres are much stronger than all other previously reported artificial filaments from cellulose nano fibrils. In fact, the artificial filaments can rival the strongest natural cellulose pulp fibres extracted from wood at the same degree of alignment of the nano fibrils. “In principle, we can make very long fibres,” says Lundell. “Up until now we have made samples that where ten centimetres long or so, but that is more of an equipment issue than a fundamental problem.”

For their experiments, the researchers have used nano fibrils extracted from fresh wood. “In principle, it should be possible to obtain fibrils from recycled paper also,” says Lundell. But he cautions: “The potential of recycled material in this context needs further investigations.”

Here’s a link to and a citation for the published paper,

Hydrodynamic alignment and assembly of nano-fibrils resulting in strong cellulose filaments by Karl M. O. Håkansson, Andreas B. Fall, Fredrik Lundell, Shun Yu, Christina Krywka, Stephan V. Roth, Gonzalo Santoro, Mathias Kvick, Lisa Prahl Wittberg, Lars Wågberg & L. Daniel Söderberg. Nature Communications, 2014; DOI: 10.1038/ncomms5018

This is an open access paper.

I posted a June 3, 2014 item on cellulose nanofibriil titled:  Doubling paper strength with nanofibrils; a nanocellulose.

Doubling paper strength with nanofibrils; a nanocellulose story

A June 3, 2014 Cerealus news release on PR Newswire announces a successful commercial trial for a new nanoscale process making paper stronger,

Cerealus, working with the University of Maine Process Development Center continues to be a leader in innovative technologies for Paper and Forestry research. Utilizing Cerealus’ unique starch encapsulation technology and UMaine’s proprietary developments, the collaborative effort enabled a novel bio-based cellulose nanofibrils (CNF) process to be used in paper and paperboard manufacturing at significantly higher levels than previously possible to develop high strength, lightweight and lower cost paper and paperboard.

The latest commercial trial doubled cellulose Nanofibril utilization in paper with the patent pending starch encapsulation technology, marketed as Cerenano™. This project confirms the promise of nanotechnology to deliver dramatic improvement in sheet density, porosity, surface quality and Z-direction strength (internal bond). Paper mills can expect:

  •     Tighter sheet
  •     More uniform surface
  •     Better printability
  •     Reduced opacity
  •     Reduced energy requirements

The collaborative private/public partnership has significantly improved the economic prospects for deploying nanotechnology in paper, wood and forestry products. A recent report estimates the current addressable market for nano cellulose at $500 million for North America.

Mike Bilodeau, Director of the UMaine Process Development Center underscored the commercial scalability of this project by saying, “This technology represents a significant break-through in the ability to leverage the unique properties of cellulose nanofibrils in paper and paperboard products.”

Tony Jabar, CEO and founder of Cerealus goes on to say, “Cerealus takes great pride in taking a lead role to create cutting edge nanocellulose technology. Successful paper makers appreciate innovation as a key to sustained profitability in the challenging paper making sector of our economy. This new development is our third generation technology and demonstrates the value of our collaboration with the University of Maine Process Development Center.”

Cerenano™ is a high performance additive that enables efficient loading of high levels of starch thus creating strong internal bond strength. The successful commercial trial demonstrated positive economic benefits and commercial scalability. The likely next phase in product development will be size press applications.

The University of Maine is working with several private companies and federal agencies to accelerate the commercialization of cellulose nanofibrils. This effort has significant implications to the health of National Forests and private timberland, as well as strategic and economic impacts to the domestic Forest Products Industry.

You can find Cerealus here and Cerenano™ page here where there’s a link to a 50 pp. presentation on Cerenano. From the presentation,

Using Renewable Nanotechnology (and Other Novel Approaches) to Improve Base Paper Performance
AWA Conferences & Events
AWA Silicone Technology Seminar 2014
March 19, 2014
Park Plaza Hotel Amsterdam Airport
Amsterdam, Netherlands
Robert Hamilton
President
Stirling Consulting, Inc.

I was particularly interested to see this (from p. 3 of the presentation),

Cellulose Nanofibrils (CNF)
The Renewable Nanomaterial

• CNF can be made from any plant matter.
# Process uses a series of mechanical refining steps.
# Resulting material is FDA compliant and compatible with any aqueous system. CNF is cellulose.

• Not to be confused with Cellulose NanoCrystals (CNC)
# Produced using more expensive strong acid hydrolysis process.

It’s the first time I’ve stumbled across a comparison of any kind between CNC (also known as NCC, nanocrystalline cellulose) and CNF and I find it quite instructive.