Acrylic acid and N-isopropylacrylamide were grafted from their binary mixtures in water onto polytetrafluoroethylene films gamma-preirradiated in air. Effects of preirradiation dose as well as temperature of grafting on efficiency of this process were investigated, the optimal values of dose and temperature were 20 kGy and 50 degreesC, respectively. The calculated monomers reactivity ratios by their graft copolymerization (r(1) and r(2)) were 0.35 and 0.01, respectively. The grafted copolymers exhibited a temperature-responsive character in the range of 17-30degreesC.