Supported silk fibroin/poly(vinyl alcohol) membrane blends: Structure, properties, and ethanol dehydration by pervaporation

Supported hydrophilic silk fibroin/poly(vinyl alcohol) (PVA) films were produced and applied in ethanol dehydration by pervaporation. Silicone treated filter paper acted as a porous layer and dimethylurea was used as crosslinking agent. The morphological and physical characterization indicated that PVA was necessary to obtain an adequate morphology, while the mechanical properties were mainly influenced by the support. In pervaporation tests conducted at 666.6 Pa and 20 degrees C, for a feed content of 14.3 mol%, a permeate water concentration of 74.6 mol% was achieved, corresponding to a separation factor of 23.7, showing a preference for the permeation of water in the blend. The feed composition was found to have a major influence in the pervaporation, swelling, and sorption experiments. The pervaporation experiments showed that the selectivity of the fibroin/PVA blends was higher than that of the pure PVA membranes, suggesting that the selectivity for water was due to the presence of fibroin, the PVA acting mainly as a plasticizer. POLYM. ENG. SCI., 58:1879-1887, 2018. (c) 2017 Society of Plastics Engineers