DEC 20, 2013 12:00 AM PST

Modeling of Cellulose Nanocrystals Suggests Amazing Strength

WRITTEN BY: Jen Ellis
Crystalline cellulose structures are known to have great strength compared to their weight, but quantifying this on the nanostructural level has been difficult. Researchers at Purdue University, the GM R&D Center, and the Forest Products Lab at the US Forest Service, used quantum mechanics principles to predict the strength of nanocrystalline cellulose, and concluded that they have a stiffness value in the range of steel. This work was published in the recent issue of Cellulose.

With a nanocrystalline structure in the range of 500 nm (nanometers) in length and widths around 3 nm, their dimensions are similar to carbon nanotubes that are currently used as strength-reinforcing additives in a wide variety of composite applications (everything from airplane and automotive components to golf clubs and tennis rackets). However, carbon nanotubes are relatively expensive to produce; whereas nanocrystalline cellulose could theoretically be recovered out of waste streams from existing industries (such as paper mills or biofuel conversion facilities).

If the strength of nanocrystalline cellulose can be confirmed and their mechanical properties fully characterized, these materials could offer a great alternative as additives to strengthen composites. By definition, they represent a "greener" process-made from renewable materials and potentially from waste streams-and depending on the technology required to extract the nanocrystalline structures, potentially a carbon-neutral product.

The research team was able to model the atomic structure of cellulose with high precision and determined that nanocrystalline cellulose has a Young's modulus value (stiffness) near 206 GPa (gigapascals). For reference, concrete is in the area of 30 GPa, ASTM-A36 steel is approximately 200 GPa, and individual carbon nanotubes can vary from near 100 GPa to 1500 GPa depending on their structure.

Nanocrystalline cellulose could be an economical, green alternative for strengthening additives-and depending on how the structure can be altered and chemically functionalized; it may have a wider variety of uses. Anything from drug delivery vehicles to purification filters to electronics industry coatings is a potential use, if the chemists in that industry can modify the structure for their needs without reducing its inherent strength.

There are other obstacles to consider, aside from convincing industries to invest in recovery processes. Cellulose's biodegradability may be an asset in some applications and an obstacle in others. If the material is being processed as nano-scale particles, it will undergo EPA and health hazard scrutiny just like other nanomaterials. Finally, some form of bulk measurement will eventually be necessary. Some carbon nanotubes in the same predicted stiffness range as individual nanotubes were found to have orders-of-magnitude lower stiffness in bulk measurements, making them useful for some industries and less so for others.

The researchers at Purdue are planning to apply the same research to alpha-chitin, a material abundant in the shells of crustaceans and insects. The mechanical properties are thought to be similar to cellulose, and alpha-chitin is a waste product of the seafood industry, so it could represent another renewable tool for composite designers and materials engineers to use.

This work represents a milestone toward the possibility of greener, renewable, economically viable materials for high-strength, lightweight applications. It's possible that your car or golf clubs will contain some of these materials within a decade or two.
About the Author
You May Also Like
AUG 08, 2021
Earth & The Environment
The Surprising Source of Life in the Arctic
AUG 08, 2021
The Surprising Source of Life in the Arctic
According to a new study published in Nature Communications last January, life in the waters of the Arctic Oce ...
SEP 28, 2021
Earth & The Environment
How to Save the World's Coral Reefs? Global Reforestation
SEP 28, 2021
How to Save the World's Coral Reefs? Global Reforestation
With recent news of the world's coral supply standing at just 50% of what it was in the 1950s, any strategies for protec ...
OCT 16, 2021
Cell & Molecular Biology
Microtubules Found to Act as Mechanosensors
OCT 16, 2021
Microtubules Found to Act as Mechanosensors
As organisms grow, live, and move through the world, they're subjected to an array of internal and external forces. Biol ...
OCT 27, 2021
Earth & The Environment
To Combat Deforestation, Research Reveals that Policy Timing is Key
OCT 27, 2021
To Combat Deforestation, Research Reveals that Policy Timing is Key
A duo of Stanford researchers have recently released a study in Global Sustainability that reveals the timing of policy ...
NOV 09, 2021
Clinical & Molecular DX
A New Light: How a Particle Accelerator Helped Solve a COVID Mystery
NOV 09, 2021
A New Light: How a Particle Accelerator Helped Solve a COVID Mystery
We know that the coronavirus wreaks havoc on the lungs. About 14 percent of cases are severe, with patients’ lungs ...
NOV 18, 2021
Chemistry & Physics
Observing Iron Under Extreme Pressure
NOV 18, 2021
Observing Iron Under Extreme Pressure
Iron is an essential component of many specialized materials. In research, we subject it to extreme conditions daily to ...
Loading Comments...