Posted on behalf of Richard A. Lovett
In the iconic sixties film The Graduate, a young Dustin Hoffman is famously told the secret to success boils down to one all-important word: plastics. Today, if Narendra Reddy has anything to say about it, the same scene would unfold with a new buzzword: chicken-feathers.
That’s because Reddy, a materials scientist at the University of Nebraska, Lincoln, is exploring a scheme to reduce petroleum use by making plastics from chicken feathers. In the process, he and his colleagues say they can not only save hundreds of millions of gallons of oil, but solve a hefty waste-disposal problem.
“More than 3 billion pounds of chicken feathers are produced in the U.S. alone each year,” said Reddy during a presentation at a meeting of the American Chemical Society in Anaheim, California. “Most of these are disposed of in landfills because there is not much use for them.”
Reddy’s team believes making plastic from feathers is a win-win for the environment. Not only would it reduce fossil fuel use, it would be biodegradable and help reduce the prevalence of long enduring plastic in the environment.
In theory, the feathers, composed largely of the protein keratin (also a constituent of human fingernails), could be processed into animal feed. But that was banned in 1997, due to concerns about the spread of diseases such as BSE (mad cow disease) from the conversation of slaughterhouse leftovers to animal feed.
Other efforts to make plastic from the feathers have attempted to extract the keratin and use it directly, but the extraction process damages it, Reddy says. “So we keep the native structure of the feathers intact.”
The process begin with a finely ground feather dust, which is provided by an outside supplier. Previous efforts to turn the dust into something that could replace conventional plastic were less than satisfactory because the resulting material did not hold up well when wet. Reddy’s team hit on the idea of chemically grafting conventional oil-based polymers onto the feather particles. This allowed them to make a feather-based thermoplastic that can be extruded and molded into any desired shape.
To date, the team hasn’t gone beyond making test films of the material and proving that grafting polymers onto feathers is a good approach. “We found that they have very good properties,” Reddy says. “The mechanical strength is high compared to other biopolymers and the films are water stable. These are both important.”
And there shouldn’t be any risk of disease transmission from the chickens, he says. The thermoplastic moulding process requires a temperature of 179°C, high enough that it should kill any disease organisms that might be present, such as avian flu viruses.
Because it requires conventional polymers for the grafting process, the technique still uses oil, Reddy says. But that doesn’t mean it isn’t saving petroleum. Each kilogram of feathers is one kilogram of petroleum that isn’t needed.
If all the waste chicken feathers in the U.S. were swept together and used for plastic, they would total about 3 billion pounds a year. That’s enough to save about 400 million gallons of oil a year– not a vast amount, but still a couple of gallons of gas for every driver in the U.S.
And that’s just from chickens. In another presentation at this week’s meeting, Fehime Vatansever, a materials scientist from Clemson University, Clemson, South Carolina, reported that bioplastics can also be made out of bone meal, a slaughterhouse waste once used for animal feed but now expensively decontaminated and landfilled to prevent the spread of mad cow disease. That totals 9 billion pounds of potential plastic feedstock per year, she said.
And a team from the University of Cambridge, UK reported that it has found a way to use microwave heating to convert the world’s 9 billion gallons of waste crankcase oil into reusable oil with about 90 percent efficiency.
None of these alone will save the planet. But bit-by-bit, they add up, scientists say.