Amorphous films of syndiotactic polystyrene were crystallized in dichlorome
thane, to obtain samples in the clathrate delta form; successively the samp
les were either annealed at temperatures below the glass transition tempera
ture (T-g) or extracted with acetone. The samples obtained show, in the X-r
ay analysis, crystalline structures tending toward the "emptied" delta form
, free of solvent molecules, as already described for sPS. The study of the
transport properties, diffusion and sorption of dichloromethane vapor, sho
ws that the annealed samples are characterized by a slightly lower diffusio
n coefficient, but much higher sorption at low activity of the vapour. This
high sorption is explained by the penetration of solvent molecules both in
to the amorphous and the "emptied" crystalline phase, producing again the c
lathrate form at low vapour activity. The high sorption capability makes th
ese samples promising as sorption media to remove traces of polluting chlor
inated solvents both in the liquid and in the vapour phase.