Simulations of gas transport in membranes based on polynorbornenes functionalized with substituted imide side groups

摘要

This paper studies the diffusive and sorption steps of several gases across membranes cast from poly(N-phenyl-exo,endo-norbornene-5,6-\uddicarboximide) chloroform solutions. Chains packing effects on gas transport was investigated by conducting a parallel study on the permeation\udcharacteristics of membranes cast from hydrogenated poly(N-phenyl-exo,endo-norbornene-5,6-dicarboximide) chloroform solutions. The permeability\udcoefficients of several gases in the two membranes were measured finding that hydrogenation of the norbornene moieties decreases gas\udpermeability. The transition states approach was used to determine the trajectories of the gases in the two types of membranes from which the\uddiffusion coefficients were obtained. Monte Carlo techniques based on theWidom method were used to simulate gas sorption process as a function\udof pressure. The values of the solubility coefficients thus obtained undergo a relatively sharp drop at low pressures approaching to a constant\udvalue as pressure increases. With the exception of carbon dioxide, pretty good agreement between the experimental and simulated values of the\udpermeability coefficient is found for the gases studied