Radiation-induced graft copolymerization of some vinyl monomers onto waste rubber powder

Rubber powder was subjected to graft copolymerization with different vinyl monomers such as acrylamide (AAm), acrylic acid (AAc), and acrylonitrile (AN). Graft copolymerization of these monomers onto rubber powder was carried out using gamma radiation. The effects of different parameters such as monomer concentration, radiation dose, inhibitor concentration, and type of reaction solvent on the graft yield were studied. It was found that the maximum graft yield obtained is 90%, 24%, and 42% for AAc, AAm, and AN, respectively. The grafted rubber powder obtained was tested as ion exchanger for copper and lead, and its capacity for ion recovery was found to be dependent on the type of monomer and graft yield. For instance, polyacrylamide and sodium salt of polyacrylic acid grafted onto rubber powder are more efficient as ion exchangers for both copper and lead ions than polyacrylonitrile. Amidoxime derivative of polyacrylonitrile is more efficient as ion exchanger than the parent polyacrylonitrile.