The links include a good article on the subject and covers the industry well.
I do not know now degradable this form of plastic actually is. You can be sure that the promoters will suggest far more than can be delivered. I suspect that it is not unless it is designed in.
This is a cause that all the globe can get behind and implement by the simple process of phasing out the old over ten years. The ocean problem informs us that it must be done.
One way we can conserve oil and solve a big pollution problem is by switching to bioplastics. We now use from 5% to 10% of our oil to make plastics. Plastics are a huge environmental problem. Many of the products made from plastics are disposables. Much of it is packaging. It ends up in our landfills and polluting the land and sea. Plastics are generally not biodegradable.
The amount of plastic pollution in the oceans is astounding. There is a sea of plastics as large as the United States in the Pacific Ocean. The winds and currents in the north pacific circulate clockwise, gathering bits of plastic into the center. The plastic breaks down into tiny bits small enough to be inadvertently ingested by creatures at the bottom of the food chain.
Here's what DR. Marcus Ericson of the Algalita Marine Research Foundation has to say about this phenomena.
"Most plastic floats near the sea surface where some is mistaken for food by birds and fishes. Plastics are carried by currents and can circulate continually in the open sea. Broken, degraded plastic pieces outweigh surface zooplankton in the central North Pacific by a factor of 6-1. That means six pounds of plastic for every single pound of zooplankton." "Storms flush plastics down stream and ultimately into the ocean. Plastic debris looks bad, but it behaves worse. Far worse! Plastic pollution negatively effects trillions upon trillions of ocean inhabitants and ultimately humans."
"Plastic pieces can attract and hold hydrophobic elements like PCB and DDT up to one million times background levels. As a result, floating plastic is like a poison pill. As a result, new research regarding endocrine disrupters in floating plastic debris is being planned by the Algalita Marine Research Foundation.. "Synthetic Sea" is a documentary based on scientific findings backed by published scientific papers."
By far the best and most promising technology is from a company called Metabolix. They are building their first factory in Iowa in a joint venture with Archer Daniels Midland, one of the large purveyors of corn products. The joint venture is called Mirel. The plastic they make is called PHA. This plastic has better biodegradability than any other, and their manufacturing process is more efficient and has less steps than that used by other companies.
"But what's really clever about Mirel is the way it is "grown". Most modern bioplastics are manufactured by extracting starch from maize or other crops and fermenting it to produce an acid, which then undergoes a series of chemical treatments to create a plastic polymer. (lactic acid -hence polylactic acetate or PLA)The scientists at Metabolix have engineered microscopic bacteria to do all that work for them. They add sugar from the maize, as well as oxygen, and watch the microbes swell as tiny plastic particles form inside them. Using a secret process, the particles are then harvested to create the pellets that can be moulded into a range of products."
Metabolix is currently using corn as the feedstock, but is looking to non food crops for the future. What is really impressive about Mirel plastics is that they are not just biodegradable, they are actually compostable. Other bioplastics need to be heated to 150% or so before they are compostable. This is not the case with Mirel bioplastics.
"Mirel has the physical properties to be a useful alternative to most traditional plastics," says Barber.
From the Metabolix website:"Metabolix today produces a broad family of these natural plastics through the fermentation of plant sugars and oils using microbial biofactories. These materials range in properties from stiff thermoplastics suitable for molded goods, to highly elastic grades, to grades suitable for adhesives and coatings. In some cases, Metabolix natural plastics offer combinations of properties not available in synthetic materials. For example, the combination of excellent water resistance with biodegradability allows flushable personal hygiene products and wet wipes."
That's not all. What is truly amazing is that Metabolix has developed a process for growing plants, with the plastic already in the stems and leaves of the plant! They have done this using switchgrass on a small scale and are further developing this process with a grant from the federal government. My first reaction, when hearing about this, was that they must be genetically modifying the plants. We all know how controversial GM crops are. That is not what they are doing. They are genetically modifying the bacteria that breaks down the sugars and starch, producing the plastic.
"In the future, Metabolix natural plastics will be produced directly in plants, making them cost-competitive with even general purpose resins such as polyethylene, and environmentally friendly alternatives to over half of the plastics used today."
"Metabolix will produce PHA Natural Plastics directly in non-food crop plants to provide cost-competitive alternatives to such widely used plastics as polyethylene, polystyrene, polypropylene, and PET, and useful raw materials for a variety of currently important chemicals. These new plastics, however, will be agriculturally produced from annually renewable resources and can be incinerated or composted with no net increase in atmospheric carbon dioxide over their lifecycle, including harvesting, isolation, and incineration or composting."
Metabolix is also developing technology to produce feedstock for biofuels as a byproduct of their bioplastics processing.
http://www.metabolix.com/Plastics Engineering's June 2007 issue had a cover story about the bioplastics industry.
Here's a link.
Cereplast is another bioplastics company.
The article gives overviews of many more companies involved with bioplastics.