Separation of polyvinyl chloride from plastic mixture by froth flotation after surface modification with ozone

Selective modification by ozonation for the surface of polyvinyl chloride ( PVC) was evaluated to separate PVC from the other plastics, polyethylene terephthalate ( PET), polycarbonate ( PC) and polymethyl methacrylate ( PMMA), with almost the same density as PVC by the froth flotation process. Ozonation could selectively decrease the contact angles of flexible PVC from 87.5 degrees to 68.4 degrees and rigid PVC from 90.3 degrees to 66.9 degrees, whereas little decreases in the contact angle were observed for other plastics. This would be due to the replacement of the chloride group on the surface of PVC, into hydrophilic functional groups; carbonyl, carboxyl and ester group. The PVC was successfully separated from the other plastics by the froth flotation process after the selective surface modification by ozonation.