| Abstract: | Hydrophilic carboxyl-containing fluoromembranes were obtained by preirradiation grafting of acrylic acid onto ethylene-tetrafluoroethylene film. The dependence of the grafting reaction on temperature, monomer concentration, nature and concentration of inhibitor, crosslinking agent, solvent, and on the preirradiation dose was investigated. The grafting rates increase with temperature, whereas the saturation degree of grafting (SDG) decreases. Addition of inhibitor minimizes homopolymerization and at the same time hinders the grafting reaction. The SDG increases markedly with monomer concentration until it reaches a maximum and thereafter decreases. The grafting rates increase with preirradiation dose. Addition of crosslinking agent initially decreases the SDG, and thereafter increases. The highest grafting rates are obtained using water as solvent followed by methanol and ethanol. The results are discussed on the basis of various parameters: interaction between monomer diffusibility and the viscosity of the monomer bath, the mutual reactivity of monomer, and the crosslinking agent. An agreement is observed between the values of the electrical resistance and the saturation degree of grafting. © 1996 John Wiley & Sons, Inc. |
