Nanostructured Poly(styrene-b-butadiene-b-styrene) (SBS) Membranes for the Separation of Nitrogen from Natural Gas

• Published in: Advanced functional materials Vol. 22; no. 8; pp. 1759 - 1767
• Main Authors: Buonomenna, Maria Giovanna, Golemme, Giovanni, Tone, Caterina Maria, De Santo, Maria Penelope, Ciuchi, Federica, Perrotta, Enrico
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 24.04.2012; WILEY‐VCH Verlag
• Subjects: block copolymers; gas separation; nanostructured membranes; poly(styrene-b-butadiene-b-styrene)
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201101904

The preparation and characterization of new, tailor‐made polymeric membranes using poly(styrene‐b‐butadiene‐b‐styrene) (SBS) triblock copolymers for gas separation are reported. Structural differences in the copolymer membranes, obtained by manipulation of the self‐assembly of the block copolymers in solution, are characterized using atomic force microscopy, transmission electron microscopy, and the transport properties of three gases (CO2, N2, and CH4). The CH4/N2 ideal selectivity of 7.2, the highest value ever reported for block copolymers, with CH4 permeability of 41 Barrer, is obtained with a membrane containing the higher amount of polybutadiene (79 wt%) and characterized by a hexagonal array of columnar polystyrene cylinders normal to the membrane surface. Membranes with such a high separation factor are able to ease the exploitation of natural gas with high N2 content. The CO2/N2 ideal selectivity of 50, coupled with a CO2 permeability of 289 Barrer, makes SBS a good candidate for the preparation of membranes for the post‐combustion capture of carbon dioxide. Tuning the morphology of poly(styrene‐b‐ butadiene‐b‐styrene) (SBS) co‐polymer membranes by means of the preparation procedure enhances the selective permeation of methane and CO2. New SBS membranes with outstanding gas separation properties are reported.