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A B S T R A C TThis article presents the results concerning the preparation of asymmetric polyamide-6 (PA-6) membrane using the wet phase inversion technique. The membrane was prepared from a casting dope containing 20 wt.% of PA-6 in formic acid at 18˚C. The membrane was then characterized by scanning electron microscopy and further tested for the separation of methanol/methyl acetate solutions by pervaporation. The effects of feed methanol concentration, operating temperature and the feed liquid flow rate on the membrane performance were investigated. The permeation flux increased with increasing feed methanol concentration, feed temperature, and feed flow rate. Some typical data of separation factor were: at the operating temperature of 40˚C, feed 80% methanol/20% methyl acetate and the feed liquid flow rate of 16.5, 20.6 mL/s, the separation factor was 50 and 83 respectively.

Nanocomposite vulcanizates comprising the poorly compatible acrylonitrile butadiene rubber/styrene butadiene rubber blend are homogenized with 20 parts per hundred montmorillonite forms showing various levels of amphiphathicity: slightly hydrophobic (Mont‐25/50) and highly hydrophobic (Mont75/100) as compared to the highly hydrophilic pristine form (Mont‐0). The purpose of the amphiphathicity is to afford simultaneous binding sites for the poorly compatible components. Thus maximum compatibility is reached with either Mont‐75 or Mont‐50 which improves the mechanical properties. Scanning electron microscopy corroborates cocontinuous morphology. Water vapor permeation through sheets/membranes fabricated from these compositions follows best performance with Mont‐25 followed by Mont‐50 while Mont‐75 and Mont‐100 based membranes acquire an organized continuous drop. This highlights the role of organophilicity in dominating the morphology and performance in pervaporation application. Dehydration of butanol is effective using such membranes with superiority for Mont‐25 based membrane. A plausible model for the transport mechanism was proposed and supported by activation energy calculations for the permeation of the individual components and the sorption affinity measurements as well. All these parameters together suggest the arrest of the n‐butanol within the macrmolecular chains of the membranes, favored by its chemical affinity. This allows therefore a passageway for the water to cross to the other side of the membrane through plasticization of the chains and creation of free volumes which is known as solution diffusion mechanism. POLYM. ENG. SCI., 54:1560–1570, 2014. © 2013 Society of Plastics Engineers

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