Gas sorption in new fluorine containing polynorbornenes with imide side chain groups

摘要

The synthesis of (N-3,5-bis(trifluoromethyl)phenyl-exo-endo-norbornene-5,6-dicarboximide) as well as the ring opening methatesis polymerization (ROMP) of this monomer to yield poly(N-3,5-bis(trifluoromethyl)phenyl-exo-endo-norbornene-5,6-dicarboximide) are reported. The glass transition of the polymer is 162 degrees C. Solubility coefficients of different gases (nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, propane, and propylene) in membranes prepared by casting from poly(N-3,5-bis(trifluoromethyl)phenyl-exo-endo-norbornene-5,6-dicarboximide) solutions were measured at several temperatures and pressures. The interpretation of the sorption results by the dual-mode model gives the Henry and Langmuir contributions to the solubility. As usual in glassy membranes, sorption processes are exothermic and the activation energies associated with the Henry and Langmuir parameters are also negative. Gas sorption in the continuous amorphous phase was interpreted in terms of the Flory-Huggins theory obtaining reasonable values for the enthalpic parameter chi that accounts for the gas (in liquid form)-polymer interactions. The use of this approach to simulate gas sorption in polymers is discussed.