Radiation initiated graft copolymerization of N-vinylpyrrolidone and acrylamide onto low density polyethylene films by individual and binary system

A study has been made for the preparation of membranes by the direct radiation grafting of N-vinyl pyrrolidone (NVP), acrylamide (AAm) and its comonomer onto low density polyethylene (LDPE) films. The factors affecting the grafting process such as solvent, inhibitor, radiation dose, dose rate, monomer and comonomer concentrations on the grafting yield were studied. Dioxane was chosen as a diluent and the addition of any inhibitor failed in this grafting system. The optimum comonomer composition at which the highest grafting yield was obtained, was found to be (20/80 wt% of AAm/NVP) comonomer.The dependence of the grafting rate upon NVP, AAm and its comonomer concentration for comonomer composition (50/50 and 20/80 AAm/NVP) was found to be 1.7, 1.44, 1.9 and 1.7 order, respectively. Some selective properties of the graft copolymers such as, swelling behaviour, electrical and mechanical properties were investigated. On the other hand, the thermal stability of these membranes was measured by using differential scanning calorimetry (DSC). An improvement of these properties was observed which makes possible the use of these membranes in some practical applications such as the removal of some heavy metals from waste water. (C) 1998 Elsevier Science Ltd. All rights reserved.