Radiation-induced grafting of sulfonates on polyethylene

Indirect methods for introducing sulfonate groups into polyethylene, using the preirradiation technique, were studied. One of the methods involved graft polymerization of 2,3-epoxypropyl acrylate into polyethylene followed by sulfonation of the epoxy ring with bisulfite. The hydroxy sulfonate thus obtained was unstable in an acid or base environment and hydrolyzed at the esteric bond. The second method involved hydrophylization of the polyethylene by forming a pregraft of polyacrylic acid or polyvinyl alcohol, followed by preirradiation grafting with sodium styrene sulfonate or, less successfully, with sodium vinyl sulfonate. The sulfonates thus obtained were resistant to acids and bases. The acid capacity, water absorption, and water permeability of the grafted films were determined.