Blends of a Polymer of Intrinsic Microporosity and Partially Sulfonated Polyphenylenesulfone for Gas Separation

• Published in: ChemSusChem 2016-08, Vol.9 (15), p.1953-1962
• Main Authors: Yong, Wai Fen, Lee, Zhi Kang, Chung, Tai-Shung, Weber, Martin, Staudt, Claudia, Maletzko, Christian
• Format: Article
• Language: English
• Subjects: Blends; Carbon dioxide; co-solvent; Gas separation; Gases - chemistry; Gases - isolation & purification; Membranes; Membranes, Artificial; Microporosity; Models, Molecular; Molecular Conformation; Molecular interactions; Natural gas; Permeability; plasticization; Polymer blends; polymers; Polymers - chemistry; Porosity; Separation; Solvents - chemistry; Sulfonic Acids - chemistry
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201600354

Polyphenylenesulfone (PPSU) and sulfonated polyphenylenesulfone (sPPSU) are widely used for liquid separations in the medical and food industries. However, their potential applications for gas separation have not been studied extensively owing to their low intrinsic gas permeability. We report here for the first time that blending with sPPSU can significantly improve the gas separation performance of highly permeable polymers of intrinsic microporosity (PIMs), specifically PIM‐1, because of the strong molecular interactions of the sulfonic acid groups of sPPSU with CO2 and O2. In addition, a novel co‐solvent system has been discovered to overcome the immiscibility of these polymers. The presence of a higher degree of sulfonation in sPPSU results in better gas separation performance of the blend membranes close to or above the Robeson upper bound lines for O2/N2, CO2/N2 and CO2/CH4 separations. Interestingly, the blend membranes have comparable gas selectivity to sPPSU even though their sPPSU content is only 5–20 wt %. Moreover, they also display improved anti‐plasticization properties up to 30 atm (3 MPa) using a binary CO2/CH4 feed gas. The newly developed PIM‐1/sPPSU membranes are potential candidates for air separation, natural gas separation, and CO2 capture. Two is better than one: A novel co‐solvent system is developed to promote the miscibility between polymers of intrinsic microporosity (PIM‐1) and sulfonated polyphenylenesulfone (sPPSU). sPPSU significantly enhances the gas separation performance of PIM‐1 in their blend membranes owing to strong molecular interactions between the sulfonated acid groups of sPPSU and CO2 or O2. These blend membranes are potential candidates for gas separation applications.