New High Permeable Addition Poly(tricyclononenes) with Si(CH<sub>3</sub>)<sub>3</sub> Side Groups. Synthesis, Gas Permeation Parameters, and Free Volume
(increase in permeability in the series C1−C4 alkanes and negative activationenergies of permeation) indicate that these polymers reveal so-called solubility controlled permeation, which is typical for some extra-high permeability polymers. Positron annihilation lifetime spectroscopy indicated that both polymers are characterized by very large sizes of free volume elements.