Radiation Modification of Adhesion Properties of Waste Plastics

Changes in the adhesive characteristics of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, and polycarbonate films and powders as a result of irradiation with 3-MeV electrons in air have been studied. Radiolytic oxidation forms polar groups on the surface of the plastics and thus increases the surface hydrophilicity. At a dose of 100 kGy, the contact angle decreases by 6° for polyvinyl chloride and by 20° for polyethylene. The radiation-induced improvement in adhesion is mainly due to an increase in the polar component of surface energy. For polypropylene, the adhesion increases by a factor of 2.5. The use of irradiated polypropylene powder in epoxy compositions improves their stress–strain characteristics.