The future of plastics is looking very green, according to scientists at Cornell. Prof. Anil Netravali, textiles and apparel, recently published his research about biodegradable, or green, plastics in the September 2002 issue of the Journal of Materials Science.
“There are many applications where items aren’t used often and then thrown away,” Netravali said. “Consumer goods such as packaging materials or computer parts are examples of such items. After these parts become obsolete, they can easily be discarded or composted. We are basically just completing the carbon cycle.”
Whereas plastics have traditionally been synthetic polyurethane, polyethylene and polypropylene, or petroleum based polymers, neither of which decompose for several decades, Netravali used plant fibers, such as ramin and pineapple, and resin from soy protein to create these green composites.
Netravali observed several of the merits of green composites.
“While it takes wood used for furniture about 25 years to grow before it can be used, the plant fibers used here grow once a year,” he said. “These materials are also produced worldwide and can use a variety of plant based fibers that are all biodegradable.”
The main focus of Netravali’s work on these composites now is to modify the soy protein properties to make the green composites stronger, more easily processed and more moisture-resistant.
“Once these plastics absorb moisture, they degrade, their strength decreases and they swell,” Netravali explained. “Within a year or two, we will be in much better shape of getting all the desired properties.”
“In normal indoor conditions, [green plastics] are like wood. You have wood inside houses that can last for over 150 years,” Netravali said. “Green plastics can withstand the indoor environment very well for years.”
Netravali feels that once these modifications are complete, there will be much more interest in widespread use of these products.
“We hope that we can market [green plastics] in a couple of years,” said Preeti Lodha, grad, who collaborated with Netravali and Sunghyun Nam ’02 in developing the green plastics.
Although the green composites currently cost substantially more money than wood or petroleum based polymers, Netravali is confident that as its use increases, the price will drop substantially.
“Mass production is key,” he said. “Graphite fibers were initially $200 to $300 per pound. As manufacturing processes improved and graphite became mass produced, the price fell to only $10 per pound. The trick is to get more people to use it.”
Even students not directly involved with these developments recognize the potential of green plastics.
“It sounds like a really good way to deal with all the waste that tends to pile up. I like seeing progress like that at Cornell, that we can be part of working on a solution to these problems,” said Stephanie Juice ’04, President of the Society for Natural Resources Conservation.
Archived article by David Hillis