Abstract
Isothermal glass transitions of polymer/gas systems, which are observed in sorption and dilation behavior, are reviewed. An inflection point of gas-sorption isotherm was correlated to the glass transition by an extension of dual-mode sorption model to polymer/gas systems in which the polymers are plasticized by sorbed gas molecules. On the basis of the extended sorption model, dilation behavior of glassy polymers due to gas sorption was theoretically and experimentally discussed in relation to the isothermal glass transition. The isothermal glass transition can be explained by assuming two modes of sorbed molecules in glassy polymers according to the dual-mode sorption model. The two modes possess different abilities of plasticizing.
