The race to develop renewable plastics is picking up steam and poultry feathers are among the materials under consideration.
Chickens are already highly productive critters, yielding fresh eggs, tender meat and piles of raw material for fertilizer. Now add renewable plastic to the list, thanks to a University of Delaware professor who managed to make a computer circuit board out of a composite of chicken feathers and soybean oil.
What started out six years ago as something of a joke’coming up with an entry for the Delaware state fair’turned into a serious project for chemical engineer Richard Wool and his graduate students. It turns out that the feathers’actually just the downy fibers removed from the quills’when processed and combined with soybean resin and made into plastic, have some pretty desirable properties. Wool and his students found the chicken-feather circuit board had better conductivity and heat resistance than conventional plastic. What’s more, the composite’s rate of thermal expansion matches that of the wires, reducing the risk of cracks and other problems when the two expansion rates are out of whack. And in case you’re wondering, there’s not even a hint of a fried chicken odor. “We leave all the smells behind” said Wool.
Recently, computer equipment companies have expressed interest in the special resin. And now Wool’s Newark, Delaware-based company, Cara Plastics, is partnering with chemical company DynaChem to produce it. Intel is advising the company on the board’s electronic performance, and manufacturer Hunter Technology is helping with the design. The chicken-feather plastic circuit boards could move into production as soon as a customer is found.
Need For Renewables
Unusual, sure, but chicken feathers are just one of many new sources that scientists and others are looking to as potential alternatives to petroleum, one of the key ingredients in plastics. The reasons are plenty. Among them, Americans generate some 29 million tons of plastic waste every year, according to the U.S. Environmental Protection Agency, raising the urgency of developing more biodegradable, or at least recyclable, materials. Green plastics, as they’re called, are increasingly attractive as the world frets about global warming, which is caused in part by burning fossil fuels. “If you work with renewable materials, you are in fact coming up with a very good method of improving the atmosphere” Wool said.
That opportunity is no doubt one of the main reasons sustainable-plastic researchers and businesses seem to be in overdrive these days. Soybean, chicken feathers, corn and sugar cane are just a few of starting points for making green polymers. The latest news in the field comes from Brazil, where chemical giant Braskem said on June 21 it had developed the first polyethylene plastic’the kind used in items like plastic bags and drink bottles’made from ethanol derived from sugar cane. The company said in a statement it would start production in 2009 and could eventually be churning out some 200,000 tons of high-density polyethylene a year.
Typically, polyethylene is made from ethane, which usually comes from natural gas, a fossil fuel. The manufacturing process can be dirty, and it can take some 1,000 years for a polyethylene bag to break down (though many are recyclable).
Where Braskem stands apart is in its use of a renewable resource or feedstock, such as sugar cane, to make ethane, the company said. It’s unclear how much cleaner, if at all, the manufacturing process will be. “We are keeping up with the desires of consumers who are asking for renewable products” said Braksmem spokesman Nelson Letaif, who noted the S? Paolo-based company’s polyethylene will be recyclable but not biodegradable.
The U.S. Government is also in the green plastics race. On June 14, Department of Energy researchers said they had managed to derive high yields of hydroxymethylfurfural (HMF), a key building block for polymers like polyester and polyurethane, directly from glucose and fructose’two of the sugars most prevalent in nature. Scientists at the Pacific Northwest National Laboratory coaxed yields of HMF of 70 percent from glucose, found in plant starch and cellulose.
The scientists teased out a 90 percent yield from fructose, found in honey, many fruits and other sources, through the same special catalytic system using metal chlorides, an approach that results in significantly less impurities than traditional catalysts. “This is just the first step” said Z. Conrad Zhang, who led the research at the labouratory’s Institute for Interfacial Catalysis in Richland, Washington. “There are a lot of things to be done before product development.”
Cost Will Be A Barrier
Yet some plastics experts say green plastics won’t truly take hold on a wide scale until their costs match those of old-fashioned petroleum-derived plastics. “The only thing that would be news in green plastics would be if someone feels they can do it economically” said Bob Davenport of SRI Consulting, a Menlo Park, California-based research group for the global chemical industry.
Until the price of oil becomes even more dear?or biotechnology helps plants have better yields of materials suitable for producing plastic?green plastics is likely to remain more of a boutique business. “It will be quite some time in the future before we get a huge market” he said. “It is a lengthy process to full commercialization, but one worth pursuing if there are sufficient advantages?and a number of companies think so.”
For their part, the engineers at Braskem believe those days are already here. Company spokesman Letaif said its polyethylene will be “as competitive” as the traditional stuff. But Braskem also believes it may be able to charge a slight premium for the product as its clients will pay for the cachet of having renewable plastic.
Wool, the chicken apostle, said his computer circuit board is already competitive with the price of traditional circuit boards. Poultry powerhouse Tyson Foods has offered to give Wool 2 billion pounds of chicken feathers a year to continue the project. Another thumbs-up: the U.S. Department of Agriculture has awarded him $500,000 for his work, which also includes making bio-based polymers and composites from soybean oil and natural fibers. Cara Plastics, of which Wool is president and CEO, is working on making high-performance parts and structures like hurricane-resistant roofs.
We may be a few years out from slumbering on plant-starch foam mattresses. But the days of toting home chicken-feather circuit boards in sugarcane plastic bags may not be far off. That’s, of course, assuming the manufacturing costs are in line with those for traditional plastic.
Reference: www.tjols.com
