文摘
Separating azeotrope-forming solvent–water mixtures by conventional distillation poses technical, economic, and environmental challenges. Pervaporation and vapor permeation membrane technologies using water-permselective membranes provide an efficient alternative for water removal from solvents. We present here new water-selective materials, based on 1,2-polybutadiene, that address two problems reported for traditional hydrophilic membrane materials under high water activities: swelling and hydrolysis. Exposure to UV radiation and/or heat converted portions of the vinyl groups in the polybutadiene to cross-links and hydrophilic functional groups, including alcohols, ketones, and carboxylic acids. In testing with a series of alcohols, such materials displayed high water permeabilities and stable performance over several months even at the extremes of 100% water, low water (2%), and an ethanol/water vapor at 115 °C and 2.5 bar.
