IUPAC-NIST solubility data series 70. Solubility of gases in glassy polymers

Solubility of gases in polymers is an important property of polymeric mater ials relevant to many practical applications. Sorption of small molecules i n polymers is a fundamental concern in such areas as food packaging, bevera ge storage, and polymer processing. However, by far the main interest in th e solubility of gases in polymers, and especially in glassy polymers; is re lated to development of novel advanced materials for gas separation membran es. This is because the concentration gradient of a dissolved gas is the dr iving force of membrane processes. Development of these novel separation me thods resulted in a rapid accumulation, in the recent literature, of thermo dynamic data related to the solubility of gases in polymers at different te mperatures and pressures. Polymers can be regarded as special cases of medi a intermediate between liquids and solids. As a consequence, modeling of ga s sorption in polymers is very difficult and presents a permanent challenge to theoreticians and experimenters. The collection and critical evaluation of solubility data for various gas-polymer systems is relevant to both pra ctical aspects of polymer applications and to fundamental studies of polyme r behavior. This volume of the UIPAC-NIST Solubility Data Series summarizes the compilations and critical evaluations of the data on solubility of gas es in glassy polymers, It: is implied in this edition that "gases" are the components that are either permanent gases (supercitical fluids) or have sa turated vapor pressure more than 1 atm at ambient conditions (298 K). The p olymeric components of compilations and critical evaluations are primarily high molecular mass, amorphous, linear (noncross-linked) compounds that hav e the glass transition temperatures above ambient temperature. The data for each gas-polymer system have been evaluated, if the results of at least th ree independent and reliable studies have been reported. Where the data of sufficient accuracy and reliability are available, values are recommended, and in some cases smoothing equations are given to represent variations of solubility with changes in gas pressure and temperature, Referenced works a re presented in the standard IUPAC-NIST Solubility Data Series format. Depe nding on the gas-polymer system, reported data are given in tabular form or in the form of sorption isotherms. The data included in the volume compris e solubilities of 30 different gases in more than 80 primarily amorphous ho mo and copolymers. Where available, the compilation or critical evaluation sheets include enthalpies of sorption and parameters for sorption isotherms , Throughout the volume, SI conventions have been employed as the customary units in addition to the units used in original publications. (C) 1999 Ame rican Institute of Physics and American Chemical Society. [S0047-2689(99)00 305-0].