The new bioplastics, more than just forks
Meg Sobkowicz was on a fast career track in the oil industry. A bachelor’s degree in chemical engineering from Columbia University landed her a job at Schlumberger running wire-line logs on oil wells in New Mexico. Next stop was to be Casper, Wyoming, the heart of the U.S. West’s oil and natural gas boom. But she jumped off the track.
“I knew that working in the oil industry was not in sync with my values,” Sobkowicz, 28, said. “I wanted something with an alternative-energy connection.”
Now, as a doctoral student at the Colorado School of Mines in Golden, Sobkowicz is one of a growing number of chemists who are developing bio-based plastics that can supplant those made from oil. Sobkowicz is working on improving the durability of plastics derived from corn and other plants, developing nanoscale fibers from cotton to reinforce them.
Bioplastics can offer several benefits: reducing greenhouse gas emissions in the production process, minimizing toxic waste and promoting rural economic development by using local crops. They can also be biodegradable.
While disposable cutlery, food packaging and even fabrics made from corn have been on the market for several years, companies are now moving toward applications where performance, heat resistance and durability are more important. These applications typically require that biopolymers be reinforced with kenaf fiber — similar to jute — or other fillers.
Products based on durable biopolymers have begun appearing in the marketplace. Japanese companies like NEC, Unitika and NTT DoCoMo are making cellphones with casings made from bioplastics. Toyota Motor uses bioplastic reinforced with kenaf for the rear package tray in its Lexus ES300 model.
The largest commercial producer of bioplastic is NatureWorks, owned by the food-processing giant Cargill. The company’s plant in Blair, Nebraska, uses corn sugar to produce polylactide plastic packaging materials and its Ingeo-brand fibers. It churns out white pellets that other manufacturers use.
The second-largest biopolymer producer is Metabolix of Cambridge, Massachusetts. It makes a different form of polymer for applications ranging from rigid molded items to flexible film for shopping or garbage bags.
Metabolix claims that its plastics are biodegradable in environments like backyard composting bins, wetlands and the ocean. According to the Biodegradable Products Institute, bioplastics should decompose into carbon dioxide and water in a “controlled composting environment” — a municipal facility, for instance — in less than 90 days.
“A lot of bio-based products are tossed out like cigarette butts, and for various reasons never decompose,” said James Barber, chief executive of Metabolix. “I can’t conceive of a system that’s so perfect that none of this stuff will escape into nature. For the stuff that does escape, we’re a backstop, ensuring that it won’t last thousands of years.”
But representatives of the petrochemical industry point out that plastics made from fossil fuels can be biodegradable, too. And they note that most bio-based plastics, if tossed in a landfill rather than a municipal-scale composting facility, might as well be a tin can or a conventional plastic bottle.
“It’s not just bio-based versus petroleum-based,” said Judith Dunbar, director for environmental issues at the plastics division of the American Chemistry Council, which represents hundreds of plastics manufacturers.
Even some scientists who are creating bioplastics caution against overstating their benefits. John Warner, director of the Center for Green Chemistry at the University of Massachusetts at Lowell, said it was unlikely they would offer advantages in every application.
“It’s not about finding the magic material that’ll replace all bad materials,” he said. “But if you promote a replacement material, it’s got to do as good of a job, not just sell itself as a swell biopolymer. And it’s got to be cost effective. We’ll get there.”