Gas transport in fluorothiophenyl modified PVC membranes

This work reports the modification of poly(vinyl chloride) by partially replacing the chlorine atoms of the chains with moieties derived from fluorinated nucleophilic compounds: 4-fluorothiophenol, 3,4-difluorothiophenol and pentafluorothiophenol. Membranes were cast from tetrahydrofuran solutions of the modified poly(vinyl chloride)s and the permeability and diffusion coefficients of hydrogen, nitrogen, oxygen, carbon dioxide and methane through the membranes were measured using permeation techniques. The influence of both the degree of modification and the number of fluorine atoms containing in functionalizing groups on the performance of the membranes was thoroughly investigated. A permselectivity study is also presented in order to evaluate the potential applicability of the membranes for gases separation.

Research highlights▶ Permeability increases in fluorothiophenylmodified PVC. ▶ Permselectivity does not significantly change. ▶ The degree of substitution affects the permeability.