Dramatic Swelling of Copolymer Membrane Induced by Polyol-Based Antifoam Agent

Abstract

Polymer membranes represent a low cost, low energy solution to separating biologically derived chemicals from fermentation. However, the performance of these membranes is commonly limited by fouling caused by biological components, but additives are also included in typical fermentation broths that can interact with the polymer membrane. Here, we examine how a common polyol antifoam agent (Antifoam 204) dramatically swells and plasticizes a high performing biobutanol membrane copolymer of hydroxyhexafluoroisopropyl and n-butyl substituted norbornene. When equilibrated against 1 wt % (aq) butanol, the solvent in the copolymer increases from 40 vol % at 1 ppm of antifoam and >80 vol % at 100 ppm of antifoam. The effect of the antifoam on the properties of the copolymer as determined by QCM-D is much more significant than that of the butanol concentration. Even with 4 wt % butanol (greater than typically viable for biobutanol), the copolymer swells <25 vol % without the ant...