Transport of water and methanol vapors in alkyl substituted poly(norbornene)

This report examines the ability of aliphatic-substituted polynorbornenes to separate methanol vapor from water-wet air streams. Single component transport properties of water and methanol were measured for each candidate polymer at 30 °C. The diffusion coefficient, sorption coefficient, and permeability were determined by measuring the rate of mass gain or loss of a sample due to sorption or desorption. The ratio of the permeabilities of the pure components yielded the ideal selectivity. The materials studied in this were methyl-, nbutyl-, nhexyl-, and ndecyl-polynorbornene. These polymers were glassy, with Tgs of 150–380 °C, and have relatively high fractional free volumes (16–19%). The results of the study showed polynorbornenes were methanol selectivity with ideal selectivities of 1.2–9. This permeation selectivity is due primarily to the solubility selectivity of the materials.