FUNCTIONALIZATION OF POLYETHYLENE FILM BY RADIOCHEMICAL GRAFTING FOR USE AS MEMBRANES IN SEAWATER DESALINATION

Functionalization of polyethylene (PE) film with vinyl monomers contai ning polar groups can impart certain important additional properties t o polyethylene membranes. With this idea in mind, attempts have been m ade to incorporate functional groups such as nitrile and ester groups onto polyethylene film by grafting methacrylonitrile (MAN) and a binar y mixture of MAN and methylacrylate (MA) by radiochemical method. Opti mum conditions for affording maximum percentage of grafting (Pg) have been evaluated. The grafted membranes have been characterized by IR sp ectroscopy and by thermogravimetric analysis. Thermal stability of the grafted PE films was found to decrease to some extent upon grafting. Percent area change and percent swelling of the grafted films in polar and nonpolar solvents have been determined. The dimension of the graf ted films enhanced with increasing level of grafting indicating that g rafting is not only confined to surface of the film but also proceeds into the interior of the film. Desalination of a model brine solution has been qualitatively studied using PE-g-poly(MAN) and PE-g-poly(MAN- co-MA) membranes. The grafted films were capable of effecting desalina tion of model brine solutions with enhanced permeability as compared t o ungrafted PE film.