New Biodegradable Plastics Could Be Tossed into the Sea

28 05 2013

A biodegradable plastic that dissolves into nontoxic components in seawater could  make it environmentally safe to ditch “disposable” forks, spoons,  wraps and other such waste overboard from ships to free up valuable space.

“There  are many groups working on biodegradable plastics,  but we’re one of a few working on plastics that degrade in seawater,” said  researcher Robson Storey, a polymer scientist at University of Southern  Mississippi. “We’re moving toward making plastics more sustainable,  especially those that are used at sea.”

Cruise  liners, naval warships and other vessels generate huge volumes of plastic trash,  such as stretch wrap for large cargo items, food containers and eating  utensils. This junk often remains onboard for long spans of time until ships  make port. Simply dumping such junk overboard is hazardous because conventional  plastics can take years to break down and may result in toxic byproducts.

When  exposed to seawater, the new plastics can dissolve in as few as 20 days. They  are made of polyurethane modified to incorporate a biodegradable compound known  as PLGA, which is used in medical sutures.

By  varying the chemical makeup of the plastic, the scientists have developed  materials that range from soft and rubbery to hard and rigid, making them  potentially useful for a variety of applications. After they dissolve,  “our goal is for them to break down into carbon dioxide and water,”  Storey told LiveScience. Other natural organic chemical byproducts, such  as lactic acid, which is found in milk, also might be generated.

The  new plastics are denser than saltwater, making them inclined to sink rather  than float. This could help prevent them from washing up on shores and polluting coastlines, Storey said.

The  plastic is undergoing degradation testing at military and university labs, and  initial results are promising, Storey said. It has not been tested in  freshwater yet.

Future  research also has to optimize the plastics for changes in temperature,  humidity, seawater composition and other environmental conditions. The future  manufacturers of these plastics also would have to overcome legal hurdles, as  international maritime law currently forbids disposal of plastics at sea.

The  team presented their findings Tuesday at the American Chemical Society annual  meeting.





One response

20 06 2013
veterinary syringes

Excellent read! Thank you for the insightful post. Nice share!

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