Global Challenges/Chemistry Solutions

Our Sustainable Future: “Green” cars made from pineapples and bananas

June 13, 2011

Green cars

Automotive plastics of the future could
be made out of nano-sized fibers
produced from pineapples, bananas,
and other fruits.
Credit: iStock

Summary

Scientists in Brazil have developed a more effective way
to use fibers from these and other plants in a new
generation of automotive plastics that are stronger,
lighter, and more eco-friendly than plastics now in use.
They described the work, which could lead to stronger,
lighter, and more sustainable materials for cars and other
products, at the 241st National Meeting & Exposition of
the American Chemical Society (ACS). The fibers used to
reinforce the new plastics may come from delicate fruits
like bananas and pineapples, but they are super strong.

With manufacturers building hybrids that have excellent gas mileage, the next step appears to be new vehicles that are created through the fruits of workers’ labors, literally –– cars made, in part, out of bananas or pineapples. Their study, explaining how they can create stronger, lighter, and more sustainable materials for cars and other products, was presented this spring at the ACS 241st National Meeting & Exposition in Anaheim.

Here’s study lead author Alcides Leão, Ph.D., with São Paulo State University College of Agricultural Sciences São Paulo, Brazil.

“The properties of these plastics are incredible. They are light, but very strong — 30 per cent lighter and 3-to-4 times stronger than the materials used today. We believe that a lot of car parts, including dashboards, bumpers, side panels, will be made of nano-sized fruit fibers in the future.

For one thing, they will help reduce the weight of cars and that will improve fuel economy. They also will help us make more sturdy vehicles.”

Besides cutting down on weight and improving gas mileage, nano-cellulose reinforced plastics have mechanical advantages over conventional automotive plastics. These new plastics can reduce damage from heat and spilled gasoline, for example.

“These new polymers can replace certain plastics used today or can be used to reinforce materials and this is a real advantage because the fruit plastics are biodegradable. Any source of cellulose-related material could be used. In fact, sludge from pulp and paper cellulose plants could be used. This sludge pulp accounts for a huge amount of waste in Brazil and other countries. How could you use fruit to build sturdier cars, some people have asked? The fact is that the nano-cellulose fibers that go into the plastics are almost as stiff as Kevlar, the renowned super-strong material used in armor and bulletproof vests. Unlike Kevlar and other traditional plastics, which are made from petroleum or natural gas, nano-cellulose fibers are completely renewable. We now have a partnership with a Malaysian company to use these fibers to develop a bullet-proof vest.”

The process, though expensive, has a major advantage which offsets the cost, and the approach looks promising for manufacturing other products in the future. Increasing production certainly will reduce the cost.

“To prepare the nano-fibers, we inserted the leaves and stems of pineapples or other plants into a device similar to a pressure cooker. We then added certain chemicals to the plants and heated the mixture over several cycles, producing a fine material that resembles talcum powder. The process is costly, but it takes just one pound of nano-cellulose to produce 100 pounds of super-strong, lightweight plastic. So far, we’re focusing on replacing automotive plastics. But in the future, we may be able to replace steel and aluminum automotive parts using these plant-based nanocellulose materials. In addition, the new plastic could be used to build airplanes.”

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check out more of our full-length podcasts on wide-ranging issues facing chemistry and science, such as promoting public health, developing new fuels and confronting climate change, at www.acs.org/GlobalChallenges. Today’s podcast was written by Michael Bernstein. I’m Adam Dylewski at the American Chemical Society in Washington.

Alcides Leão, Ph.D.
Alcides Leão, Ph.D.,
São Paulo State University
College of Agricultural Sciences
São Paulo, Brazil