Synthesis and gas permeation properties of poly(diarylacetylene)s having substituted and twisted biphenyl moieties

Abstract

Diarylacetylene monomers containing substituted biphenyl (1a–f) and anthryl (1g) groups were synthesized and then polymerized with TaCl5-n-Bu4Sn catalyst to produce the corresponding poly(diarylacetylene)s (2a–g). Polymers 2a–f were soluble in common organic solvents such as cyclohexane, toluene, and chloroform. According to thermogravimetric analysis, the onset temperatures of weight loss of the polymers were over 400 °C in air, indicating considerably high thermal stability. Free-standing membranes 2a and 2c–e were prepared by the solution casting method. Desilylation of Si-containing membrane 2c was carried out with trifluoroacetic acid to afford 3c. All the polymer membranes, especially those having twisted biphenyl groups, exhibited high gas permeability; for example, their oxygen permeability (PO2) values ranged from 130 to 1400 barrers. Membrane 2d having two chlorine atoms in the biphenyl group showed the highest gas permeability (PO2 = 1400 barrers) among the present polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 861–868, 2010