DETERMINATION OF THE SOLUBILITY AND DIFFUSIVITY OF GASES IN POLYMERS BY USING A HIGH-PRESSURE MAGNET-SUSPENSION-BALANCE

摘要

Diffusivity and solubility of gases in polymers can be determined by employing a high-pressure magnet-suspension-balance. Since the measured weight is the difference between gravity and buoyancy, the weight displayed has to be corrected. Buoyancy is a function of gas density and the sample's volume. Whereas the gas density is contingent upon temperature and pressure, the determination of the sample's volume is more complex. The volume does not only vary in dependence on temperature and pressure but also due to the absorption of gas. A method to determine the solubility considering the swelling of polymers is shown for a polyester/CO_2-system.