Biodegradable Plastic – A Solution to the Recycling Challenge
Americans spent nearly $11 billion last year on bottled water, making it the nation’s second-favorite beverage, after soft drinks.
That’s a lot of water – and a lot of waste, environmental advocates say. It takes 1.5 million barrels of oil, enough to fuel 100,000 cars for a year, to make the plastic bottles that meet Americans’ demand for bottled water, according to the Earth Policy Institute.
The kind of plastic most commonly used for water bottles – polyethylene terephthalate, or PET – is recyclable. But consumers recycle just one of every five bottles they drink, with the rest ending up in landfills, says Pat Franklin, executive director of the Container Recycling Institute.
A common myth is that plastics that go into a curbside recycling bin get recycled. The fact is that many plastics are non-recyclable. The recyclable types must be separated out, and the rest go to waste. Many people assume that plastic collected at the curb is converted into new packaging, but plastic recycling only provides a temporary diversion from landfills. Most recovered plastic packaging is made into secondary products (textiles, parking lot bumpers, or plastic lumber) that are not recyclable.
Only two manmade structures on Earth are large enough to be seen from space: the Great Wall of China and the Fresh Kills landfill in New York.
The startup company Novomer, based in Ithaca, NY, is moving ahead with an efficient method to make affordable, biodegradable plastic made from carbon dioxide. The technology centers on a catalyst that converts carbon dioxide into a polymer that could be used to make everyday items such as packaging, milk jugs, cups, and forks. The plastic, which was originally created by Cornell chemist Geoffrey Coates, is also safe and strong enough to be used in medical implants and devices. “The plastic should be relatively inexpensive since carbon dioxide is a cheap feedstock,” says Coates.
Novomer uses raw materials – carbon dioxide and epoxides – but its product is distinguished by a metallic catalyst developed by Coates. The zinc-based catalyst works at room temperature and low pressure, and it’s faster. “Our reaction takes a matter of minutes,” Coates says. “So we can use a lot less of the catalyst.”
A process converts carbon dioxide into different forms of biodegradable polymers.
The polymer has different properties – it can be hard, soft, transparent, or opaque – based on the type of epoxide used. It is also biodegradable, since the carbon-oxygen bonds in Novomer’s polymer are relatively easy for bacteria to break down. Coates says that Novomer has not tested the degradability of the polymer, but aliphatic polycarbonates in general have been shown to degrade in six months in composts under ideal conditions.
In terms of biodegradability, the Novomer plastic will have to compete with several other plant-based plastics now on the market, including ones made by Biota, based in Telluride, CO; Metabolix, in Cambridge, MA, and NatureWorks, in Minnetonka, MN.
But Coates says that Novomer’s use of carbon dioxide and carbon monoxide as inexpensive feedstocks, instead of the corn-based feedstocks used by other biodegradable plastics, means that the company’s plastic won’t compete with food production.
With new forms of biodegradable plastics being developed and consumer awareness growing, the amount of plastics going to landfills could eventually decrease.
Source: Janet Rausa Fuller, Chicago Sun-Times