Synthesis and Properties of Membranes of Poly(diphenylacetylenes) Having Fluorines and Hydroxyl Groups

Abstract

Diphenylacetylenes possessing fluorine atom(s) and a siloxy group (1c−i) were polymerized with TaCl5−n-Bu4Sn. Monomers 1c−f having a siloxy group at the para position of a phenyl ring produced high molecular weight polymers (2c−f) in good yields. These polymers afforded tough free-standing membranes by casting their toluene solution. Desilylation of the polymer membranes was carried out with trifluoroacetic acid to give membranes of poly(diphenylacetylenes) having fluorine atoms and hydroxyl groups (3c−f). Polymers 2c−f were soluble in various organic solvents such as toluene, CHCl3, and THF, while polymers 3c−f were insoluble in these solvents. All the polymers 2c−f and 3c−f exhibited high thermal stability. The gas permeability of most membranes in the present study (2d−f and 3c−f) were higher than those of the corresponding polymers without fluorine atoms (2a and 3a), indicating that incorporation of fluorine atoms into the polymers enhances gas permeability. The PCO2/PN2 permselectivity ratios of poly...