This Small Business Technology Transfer (STTR) Phase I project focuses on vapor-selective membranes that are stabilized through the addition of nanoscale fillers. Vapor-selective membranes, which preferentially permeate the larger molecules in a gas mixture, are used in industrial separation applications such as organic monomer recovery in polyolefin production and natural gas dew point adjustment. Polydimethylsiloxane (PDMS), a membrane material with modest selectivity, is typically used in separations of this type. Polymers with superior selectivity properties have been identified, but these materials suffer performance degradation over time due to physical aging. Recently, we have discovered that the addition of certain nanoscale fillers stabilizes these highly-selective polymers. In the proposed project, such fillers will be added to high-performance, vapor-selective polymers to yield novel, stable nanocomposite membranes. <br/><br/>Successful development of the proposed membranes would allow the recovery of hydrogen from refinery streams that cannot be cost-effectively separated with conventional technologies, including currently available membranes. Flaring of these off-gas streams results in an estimated annual loss of $300 million to U.S. refineries.