Chemical separations based on absorption phenomena into syndiotactic polyst
yrene samples including a nanoporous crystalline phase are described. These
separation phenomena are due to the presence into the crystalline phase of
cavities whose size and shape have been studied through sorption experimen
ts relative to linear hydrocarbons and through calculation procedures relat
ive to the available crystalline structures of different polymorphic and cl
athrate forms of syndiotactic polystyrene.