Nav: Home

Material formed from crab shells and trees could replace flexible plastic packaging

July 23, 2018

From liquid laundry detergent packaged in cardboard to compostable plastic cups, consumer products these days are increasingly touting their sustainable and renewable origins.

Now researchers at Georgia Institute of Technology have created a material derived from crab shells and tree fibers that has the potential to replace the flexible plastic packaging used to keep food fresh.

The new material, which is described July 23 in the journal ACS Sustainable Chemistry and Engineering, is made by spraying multiple layers of chitin from crab shells and cellulose from trees to form a flexible film similar to plastic packaging film.

"The main benchmark that we compare it to is PET, or polyethylene terephthalate, one of the most common petroleum-based materials in the transparent packaging you see in vending machines and soft drink bottles," said J. Carson Meredith, a professor in Georgia Tech's School of Chemical and Biomolecular Engineering. "Our material showed up to a 67 percent reduction in oxygen permeability over some forms of PET, which means it could in theory keep foods fresher longer."

Cellulose, which comes from plants, is the planet's most common natural biopolymer, followed next by chitin, which is found in shellfish, insects and fungi.

The team devised a method to create a film by suspending cellulose and chitin nanofibers in water and spraying them onto a surface in alternating layers. Once fully dried, the material is flexible, strong, transparent and compostable.

"We had been looking at cellulose nanocrystals for several years and exploring ways to improve those for use in lightweight composites as well as food packaging, because of the huge market opportunity for renewable and compostable packaging, and how important food packaging overall is going to be as the population continues to grow," Meredith said.

The research team also included Meisha Shofner, an associate professor in the School of Materials Science and Engineering and the interim executive director of the Renewable Bioproducts Institute, John R. Reynolds, a professor in the schools of Chemistry and Biochemistry and Materials Science and Engineering, and Chinmay Satam, a graduate student at Georgia Tech.

The team had been looking into chitin for an unrelated reason when they wondered if it might have use in food packaging.

"We recognized that because the chitin nanofibers are positively charged, and the cellulose nanocrystals are negatively charged, they might work well as alternating layers in coatings because they would form a nice interface between them," Meredith said.

Packaging meant to preserve food needs to prevent oxygen from passing through. Part of the reason the new material improves upon conventional plastic packaging as a gas barrier is because of the crystalline structure of the film.

"It's difficult for a gas molecule to penetrate a solid crystal, because it has to disrupt the crystal structure," Meredith said. "Something like PET on the other hand has a significant amount of amorphous or non-crystalline content, so there are more paths easier for a small gas molecule to find its way through."

Environmentalists have long looked for renewable ways to replace petroleum-based materials in consumer products. With the amount of cellulose already produced and a ready supply of chitin-rich byproducts left over from the shellfish food industry, there's likely more than enough material available to make the new films a viable flexible-packaging alternative, Meredith said.

Still, there's more work to be done. To make the new material eventually competitive with flexible packaging film on cost, a manufacturing process that maximizes economy of scale will need to be developed. Additionally, while industrial processes to mass produce cellulose are mature, methods to produce chitin are still in their infancy, Meredith said. And, more research is also needed to improve the material's ability to block water vapor.
-end-
This work was supported by the Georgia Tech Renewable Bioproducts Institute and the Georgia Research Alliance. Any conclusions or recommendations are those of the authors and do not necessarily represent the official views of the sponsoring organizations.

CITATION: Chinmay C. Satam, Cameron W. Irvin, Augustus W. Lang, Jerel Cedric R. Jallorina, Meisha L. Shofner, John R. Reynolds, J. Carson Meredith, "Spray-Coated Multilayer Cellulose Nanocrystal - Chitin Nanofiber Films for Barrier Applications," (ACS Sustainable Chemistry and Engineering, July 2018). https://doi.org/10.1021/acssuschemeng.8b01536

Georgia Institute of Technology

Related Engineering Articles:

Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.
Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.
Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.
New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.
Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.
Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.
Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.
What can snakes teach us about engineering friction?
If you want to know how to make a sneaker with better traction, just ask a snake.
Engineering a plastic-eating enzyme
Scientists have engineered an enzyme which can digest some of our most commonly polluting plastics, providing a potential solution to one of the world's biggest environmental problems.
A new way to do metabolic engineering
University of Illinois researchers have created a novel metabolic engineering method that combines transcriptional activation, transcriptional interference, and gene deletion, and executes them simultaneously, making the process faster and easier.
More Engineering News and Engineering Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.