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Method of cleaning plastics using super and subcritical media

United States Patent

*** EXPIRED ***
5,756,657
May 26, 1998
View the Complete Patent at the US Patent & Trademark Office
A method for treating a plastic, such as polyethylene or polypropylene, to remove at least a portion of at least one contaminant includes combining the plastic with a supercritical medium, such as carbon dioxide or sulfur hexafluoride, whereby at least a portion of the contaminant dissolves in the supercritical medium. Alternatively, the plastic can be combined with a suitable liquid medium, such as carbon dioxide or liquid sulfur hexafluoride. At least a portion of the medium, containing the dissolved contaminant, is separated from the plastic, thereby removing at least a portion of the contaminant from the plastic.
Sawan; Samuel P. (Tyngsborough, MA), Spall; W. Dale (Los Alamos, NM), Talhi; Abdelhafid (Nashua, NH)
University of Massachusetts Lowell (Lowell, MA)
08/ 670,585
June 26, 1996
GOVERNMENT FUNDING This invention was sponsored by Grant No. 06-6604 provided by the Los Alamos National Laboratory, Department of Energy, and the Government has certain rights to the invention.