Permeability of Polymer Membranes Based on Polyimides Towards Helium

-The approach to the prediction of permeability of polymer membranes based on polyimides and polyamidoimides towards helium is described. According to the approach, the activation energy of helium penetration is expressed by a relationship involving the van der Waals volume of the repeat unit and a set of atomic parameters characterizing the contribution of each of the atoms and intermolecular interaction types into the value of activation energy. The contributions of the imide cycles, type of the connection (meta-, para-, or ortho-), and of the CF3, CH3, CO, Cl, F, and SO2 polar groups have been accounted for. Repeated solution of the redundant set of equations obtained on the basis of the proposed relationship has afforded the parameters giving the correspondence of the calculated values and the experimental data on the membranes permeability with correlation coefficient 0.965. Hence, the possibility to search for the structures of polyimides and polyamidoimides with the target permeability without laborious and expensive experiments has been demonstrated.

Automated summary

The approach to predict the permeability of polymer membranes based on polyimides and polyamidoimides towards helium is described. The activation energy of helium penetration is represented by a relationship involving the van der Waals volume of the repeat unit and a set of atomic parameters characterizing the contribution of each atom and intermolecular interaction types. Factors such as the imide cycles, connection type, and polar groups have been taken into account. The obtained parameters show a strong correlation coefficient of 0.965 with the experimental data, demonstrating the possibility to search for polyimide and polyamidoimide structures with the desired permeability without the need for laborious and expensive experiments.