Water Vapor and Oxygen Permeabilities of Polyetherurethanes

Abstract

Effects of soft segment content, hydrophilicity of polyether macroglycol soft segment and presence of polydimethylsiloxane co-soft segment on oxygen and water vapor permeabilities of polyetherurethanes were investigated. Polyetherurethanes were synthesized using a bulk synthesis procedure and solution cast as thin films. Oxygen and water vapor transport measurements were performed at 38 °C, 100% relative humidity (RH) and 4 mm Hg oxygen gradient, and 40 °C and 80% RH test gradient, respectively. The soft segment content and structure had profound influences on oxygen and water vapor permeabilities of the polyetherurethanes. Water vapor and oxygen permeabilities of polyetherurethanes increased with increasing soft segment content. Polytetramethylene oxide based polyetherurethanes (PTMO-PEU) had high oxygen permeabilities and polyethylene oxide based polyetherurethanes (PEO-PEU) had high water vapor permeabilities. Addition of silicone co-soft segment increased water vapor permeability and slightly reduced oxygen permeability of PTMO-PEU. Its effect on PEO-PEU was the reverse of that of the PTMO-PEU systems.