Freeze-purged-desorption method for quantitative evaluation of Co_2-solubility in polymeric films

摘要

A new experimental method, named as freeze-Purged-desorption (FPD) method, to evaluate quantitatively the amount of gases sorbed in polymeric films, has been developed by using carbon dioxide gas and five different films (low density polyethylene: LDPE, polypropylene: PP, polystyrene: PS, polyacrylonitrile copolymer: PAN, polycarbonate: PC). The FPD method consisted of three operational periods of time based on the stepwise change in the system temperatures, the freeze periods of sorbed CO_2at-196 deg.C the purging period of atmospheric CO_2 at-78 deg.C and the desorption period of the freezed CO_2 in the film at -9 deg.C. The evaluated values for LDPE, PP, PS, PAN and PC were 0.310, 0.65, 3.90, 0.098 and 6.90 (cm~3(STP)/CM~3ATM), RESPECTIVELY, WHICH WERE ABOUT 20-40/100 higher than the reference values. The validity of the method was reconfirmed by a good reproducibility of the desorption curves of sorbed gases referring to a blank curve obtained from the non-porous glass beads.