MEASUREMENT OF CO//2 DIFFUSION IN POLYMER FILMS.

A simple and sensitive method for measuring CO//2 permeability in polymer films has been developed. The method is based on the use of **1**4CO//2. At time zero **1**4CO//2 is injected on the 'high' pressure side of the cell. Permeation is monitored with a Geiger counter which senses **1**4CO//2 on the 'low' pressure side of the cell. The counts/time on the low pressure side is proportional to the total concentration of CO//2 which has diffused through the film. With the known source concentration the volume-time curve is constructed and the permeability and time lag are calculated. The system sensitivity as it is presently configured is on the order of 10** minus **1**5 cm**3 (STP) -cm/cm**2 -sec-cm Hg. Results are presented for a measurement in a 0. 025 cm polycarbonate film.