The permeabilities of CH4, CO2, CH3OH, H2O, O-2, and CO through films of Kapton(R) polyimide were measured af temperatures of 50, 100, 150, 200, and 250 degrees C and pressures below 1 atm. Apparent activation energies for the permeation of the pure components ranged from 31.6 kJ mol(-1) for CH4 to nearly 0 for H2O under the conditions studied. The ideal permselectivity for methanol relative to methane decreased from over 100 to under 10 as the temperature was increased from 50 to 250 degrees C.