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A calculation method for prediction of water permeability through polymers is suggested. An appropriate equation for calculating the activation free energy of permeability is proposed. The method is based on a set of atomic constants associated with the polymer-water interaction energy. The chemical structure of polymers as well as the degree of crystallininty, temperature, and free volume are taken into account. The method is also applicable for polymeric nanocomposites.

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Here we use model nanocomposites based on polystyrene and polyphenylene dendrimers to show both theoretically and experimentally that inclusion of rigid nanoparticles of 2.3–5 nm size into the polymer leads to a negligible glass transition temperature (Tg) increase.

The influence of the degree of crystallinity of polymers on the glass transition temperature Tg of their amorphous domains is quantitatively analyzed. The analysis is made based on the Mandelkerns ideas [ concerning the restrictive effect of crystallization on the mobility of macromolecules within the amorphous domains. At low degrees of crystallinity, Tg of amorphous domains slowly increases, and then increases much faster at high degrees of crystallinity.