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Transforming the power of plants.

It was the early 1990s when Anil Netravali began his career at the College of Human Ecology as a fiber scientist. At the time, carbon, glass, and Kevlar composites were remaking electronics, sporting goods, military vehicles, medical devices, and other products. Netravali was developing stronger, lighter composite materials for the aerospace industry.

As a scientist, Netravali enjoyed success, including two patent-winning discoveries. Even so, he started to have second thoughts about his work.

"We were developing these composite materials with great properties, but they had some serious problems as well," he said. "Most of them are derived from petroleum, a resource that we are quickly depleting. They are not biodegradable and nearly impossible to recycle or reuse. When you break your carbon-fiber tennis racket, it's going to end up in a landfill, where it will stay for several decades, maybe even centuries."

Soon Netravali began to think about how to recreate the properties of petroleum-based composites with a renewable resource. Before long, he had his answer: plants.

"When you think about it, plants are the one replacement that is renewable, nontoxic, and nonpolluting," he said. "If you can find a way to use plant-based materials, they are safe. And at the end of their lifespan, you can simply compost them."

Netravali's laboratory in the Department of Fiber Science and Apparel Design has since developed more than a dozen new types of plant-based materials used in a wide variety of commercial applications, from skateboards to furniture to products for the health care industry.

"Companies are interested in 'green' products," he said. "This is a good thing, because it is a problem we have to solve. If we don't, nature will do it for us when we run out of petroleum."

Nanofibers for filters

For Netravali's latest project, he is partnering with Cornell chemical engineering professor Yong Joo to develop compostable, high-efficiency air and water filters made out of nanofibers that are derived from soybeans and other inexpensive crops.

The filters have tiny pores--much smaller than current air filters--so they are better able to capture molecules of dust, bacteria, and viruses. The fibers also carry a natural charge to attract and capture dust particles.

Joo and Netravali made the manufacturing process as environmentally friendly as the finished product itself. Creating filters typically uses expensive and toxic solvents, which have to be recovered and recycled. But the process they developed, called electrospinning, uses only water and protein derived from soy flour, with a supply of electricity. When the electricity is applied to the solution, the liquid forms a jet and deposits a layer of nanofibers on a metal plate.

In producing a filter, the nanofiber layer is deposited on a cellulose filter. "Thus the process uses all biodegradable materials," Joo said.

When they are used up, traditional filters are discarded and sent to landfills. ButNetravali's filters can be composted.

Sunayna Jain, a fiber science graduate student, worked with Netravali and Joo to refine the filter-making process. "Soy protein is available in three forms," she said. "Right now I'm trying to develop a way to use soy flour, which is the least expensive soy product, to make the filters."

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The concept has been licensed to Axium Nanofibers, a start-up company based in Laguna Beach, Calif., that plans to release Netravali's air and water filters for use in commercial and residential buildings and most vehicles by the end of 2012.

In addition, it will be easy to customize the filters for specific industries, Netravali said. For example, for a health care facility, fabricators can reduce the pore size to capture bacteria and viruses, and also add material that will kill germs on contact.

Later this year, Netravali will move his laboratory into the new Human Ecology Building. He expects the state-of-the-art facility and expanded space will allow him to set up his own fiber-spinning operation, where he will continue to refine the green filter technology and add more functions.

Skateboards to particle board

The compostable filters are not Netravali's first innovation in sustainability. Tn 2006, he co-founded e2e Materials in Ithaca to market his plant-based composites and resins to green manufacturers.

The company's first commercial success came with Comet Skateboards, a company committed to making nontoxic skateboards out of renewable materials. Jason Salfi '93, a co-founder of Comet Skateboards, heard about Netravali's soy-based resin and moved Comet's manufacturing operation to Ithaca to more easily partner with e2e Materials.

"For us, it's a commitment to the environment," Salfi said. "This product is a great alternative to the glues that most other companies are using. Sharing space with e2e allowed us to develop the technology a lot faster together."

Next, e2e Materials set out to create an alternative to particle board, which is used in furniture and building construction but often contains resins made from formaldehyde, a carcinogen linked to "sick-building syndrome," where chemical contaminants trapped inside of a building cause health problems for occupants

Netravali's replacement material uses a resin made of soy protein, similar to the solution used to make the nanofiber filters. The resin coats a mat woven of fibers such as jute, bamboo, or hemp, resulting in a material that is stronger than traditional particle board and weighs less.

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A new green revolution

Netravali's research interests have led him to develop a wide assortment of materials. For that, he credits the collaborative environment at Cornell.

"If I have an idea, but I don't have the expertise, I can just pick up the phone and call someone else on campus," he said. "They can take it to the next step. It's the wonderful thing about working at Cornell."

This inclusive approach has led Netravali to develop increasingly diverse products. In recent years, his lab has focused on creating new materials from the waste products obtained from the soy-protein purification process--sugars and unusable residue. So far, he has come up with three new-applications.

The first two--a coating for seeds that acts as a natural fertilizer and mulch fortified with nutrients--are collaborations with entomology professor iMichael Hoffmann and horticulture professor Alan Taylor at Cornell's New York State Agricultural Experiment Station in Geneva.

The third is a joint project with Weill Cornell Medical College and the College of Veterinary Medicine that will help patients with severe skin wounds. Netravali and collaborators are using soy carbohydrates to create a bacterial cellulose membrane that can be used to dress burns and deep cuts. It helps reduces scar tissue growth and allows new, soft skin to form more easily.

Another Netravali project is to use nanofibrils, highly organized molecules of plant cellulose, to create a resin that, along with high-strength cellulose fibers, can form composites stronger than most varieties of steel. Netravali sees applications for military vehicles and ballistics applications.

Developing environmentally friendly products with such a wide range of uses fuels Netravali's optimism.

"It's great to see that people have begun to think about this new 'green' revolution," he said. "When I started down this path, not many were talking about it. Now companies want these products, and more and more of our students are dedicated to the idea of sustainability. It's our students, the young generation, who really make me feel optimistic. When they're out in the workplace, things will change even more and even faster."

The general public can play a part too, Netravali said, simply by looking out for plant-based products.

"If people have their eyes and ears tuned to 'green,' they'll see more and more of these products," he said. "And the more people buy, the more companies will want to make. That's how it: will happen. And it will happen, because someday we will have no alternative. That' someday' will arrive soon."

For more information:

Michael Hoffmann

mph3@cornell.edu

Yong Joo

ylj2@cornell.edu

Anil Netravali

ann2@cornell.edu

Alan Taylor

agt1@cornell.edu

Anil Netravali (left) teamed up with Cornell chemical engineer Yong Joo to develop compostablet high-efficiency air and water filters made of nanofiters derived from soybeans and other inexpensive crops.

Scientist Anil Netravali creates plant-based composites, some stronger than steel, for use in sporting goods, buildings, medicine, and more.
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Author:Hall, Sheri
Publication:Human Ecology
Geographic Code:1USA
Date:Sep 22, 2011
Words:1355
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