Synthesis and Properties of Substituted Polyacetylenes Having Cyclohexyl Groups

Abstract

Disubstituted acetylenes containing cyclohexyl groups (RC≡CC6H4–p-cyclo-C6H11, R=Ph, p-Me3SiPh, p-tert-BuMe2SiOPh, Me, Cl, 1a–e, respectively) were polymerized with Ta- or Mo-based catalyst, and 1a, 1c, and 1e provided high molecular weight polymers. Free-standing membranes of poly(1a) and poly(1c) were fabricated from toluene solution. Hydroxy-containing membrane poly(2c) was prepared by desilylation of siloxy-containing poly(1c) using trifluroacetic acid. According to thermogravimetric analysis (TGA), the produced polymers exhibited high thermal stability, and the onset temperatures of weight loss in air were ∼340 °C. The oxygen permeability coefficients of these membranes were in the range of 17–230 barrers. The point of poly(2c) in the PCO2 vs. PCO2/PCH4 plot were located above Robeson’s upper bound.