April 2, 2007 -- Plastics That Dissolve In Seawater
You’ve seen plastic containers washed up on the beach or bobbing around docks. Not a pretty sight. But what if there was a way to recycle without sorting, shipping or shredding? What if plastic simply recycled itself? Scientists at the University of Southern Mississippi may have found a way. They’ve invented a line of plastics that dissolve in seawater. The new plastics are made of polyurethane that’s been modified with polylactic-co-glycolic acid, a polymer used in surgical sutures. The compound can be modified to produce flexible, soft or hard plastic. It tends to sink, not float, and in less than a month it degrades by hydrolysis into natural, nontoxic compounds. The US Navy has been funding the research, and for a good reason. All the plastic waste generated on a ship—even a floating-city aircraft carrier—has to be stored onboard until it reaches port. There are still a few kinks to work out with the new discovery. The plastics haven’t been tested in fresh water. And international maritime law doesn’t currently allow the disposal of plastics at sea. But a plastic that vanishes might make that restriction disappear.