Synthesis and Gas Transport Properties of Hydroxyl-Functionalized Polyimides with Intrinsic Microporosity

• Published in: Macromolecules Vol. 45; no. 9; pp. 3841 - 3849
• Main Authors: Ma, Xiaohua, Swaidan, Raja, Belmabkhout, Youssef, Zhu, Yihan, Litwiller, Eric, Jouiad, Mustapha, Pinnau, Ingo, Han, Yu
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.05.2012
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polycondensation; Preparation, kinetics, thermodynamics, mechanism and catalysts; Polyimide; Transport properties; Gaseous diffusion; Indan derivatives; Porous membrane; Fluorine containing polymer; Experimental study; Porous material; Polyaddition; Functional polymer; Aminophenols; Thermal stability; Pyromellitimide polymer; Gas permeability; Microporosity; Preparation; Moisture regain; Selective permeability; Soluble compound; Indene derivative polymer; Surface area; Spiran polymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma300549m

A newly designed diamine monomer, 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′-diamino-6,6′-diol, was successfully used to synthesize two types of polyimides for membrane-based gas separation applications. The novel polymers integrate significant microporosity and polar hydroxyl groups, showing the combined features of polymers of intrinsic microporosity (PIMs) and functional polyimides (PIs). They possess high thermal stability, good solubility, and easy processability for membrane fabrication; the resulting membranes exhibit good permeability owing to the intrinsic microporosity introduced by the highly contorted PIM segments as well as high CO2/CH4 selectivity that arises from the hydroxyl groups. The membranes show CO2/CH4 selectivities of >20 when tested with a 1:1 CO2/CH4 mixture for feed pressures up to 50 bar. In addition, the incorporation of hydroxyl groups and microporosity in the polymers enhances their affinity to water, leading to remarkable water sorption capacities of up to 22 wt % at 35 °C and 95% relative humidity.