Synthesis of poly[1-phenyl-2-(fluoren-2-yl)acetylene]s bearing trimethylsilyl groups at the fluorene 9-position to give highly gas-permeable polymer membranes

Abstract

Four types of 1-phenyl-2-(fluoren-2-yl)acetylene bearing SiMe3 groups at the 9-position of fluorene (1a–1d) were synthesized and polymerized in the presence of TaCl5/n-Bu4Sn to yield the corresponding polymers (2a–2d). Membranes fabricated from 2a–2c exhibited fairly high gas permeabilities (PO2: 1600–7000 barrer), while membrane 2d was too brittle for testing. As the number of SiMe3 groups in the monomer unit increased, the gas permeability of the polymer membrane increased. Desilylated membranes 3a–3c were obtained by the desilylation of membranes 2a–2c, respectively. Desilylated polymers 3a–3c possessed identical chemical structures but different gas permeabilities (PO2: 2500–5800 barrer). Highly gas-permeable polymers 2c and 3c exhibited good stabilities against physical aging in terms of their gas permeabilities.