Gas Separation Properties of Polymers Containing Fluorene Moieties

Abstract

Polymers containing fluorene moieties are interesting because of their potential applications as photoelectronic materials and as gas separation membranes. In this work, the gas transport properties of two novel poly(arylene ether)s, one containing diphenylfluorene (FBP) and 2,6-bis(trifluoromethylphenylene)pyridine (6FPPr) groups and the other containing FBP and 2,5-bis(3-trifluoromethylphenylene)thiophene (6FPT) groups in the main chain, were investigated. The influence of temperature on permeability, diffusivity, and selectivity is reported at temperatures from 30 to 65 °C. Activation energies of permeation and diffusion for He, H 2, CO 2, O 2, N 2, and CH 4 were obtained for the diphenylfluorene-containing polymers. It was found that the two FBP-containing poly(arylene ether)s studied here show higher gas permeabilities than most of the reported FBP-containing polymer membranes. A comparison revealed that the replacement of the thiophenylidene group with the pyridinylidene has an obvious influence on the gas transport properties of these polymers. The polymer membrane with the pyridinylidene group has gas separation properties superior to that with the thiophenylidene group.