Characterization of 6FDA‐based hyperbranched and linear polyimide–silica hybrid membranes by gas permeation and ¹²⁹Xe NMR measurements

Abstract

Physical and gas transport properties of novel hyperbranched polyimidesilica hybrid membranes were investigated and compared with those of linear-type polyimide-silica hybrid membranes with similar chemical structures. Hyperbranched polyamic acid, as a precursor, was prepared by polycondensation of a triamine, 1,3,5-tris(4aminophenoxy)benzene (TAPOB), and a dianhydride, 4,4 0 -(hexafluoroisopropylidene)diphthalic anhydride (6FDA). 6FDA-TAPOB hyperbranched polyimide-silica hybrids were prepared using the polyamic acid, water, and tetramethoxysilane (TMOS) by sol-gel reaction. 5% weight-loss temperature of the 6FDA-TAPOB hyperbranched polyimide-silica hybrids determined by TG-DTA measurement considerably increased with increasing silica content, indicating effective crosslinking at polymer-silica interface. CO 2 , O 2 , N 2 , and CH 4 permeability coefficients of the 6FDA-based polyimide-silica hybrids increased with increasing silica content. In addition, CO 2 /CH 4 selectivity of the 6FDA-TAPOBsilica hybrids remarkably increased with increasing silica content. From 129 Xe NMR analysis, characteristic distribution and interconnectivity of cavities created around polymer-silica interface were suggested in the 6FDA-TAPOB-silica hybrids. It was indicated that size-selective separation ability is effectively brought by the incorporation of silica for the 6FDA-TAPOB hyperbranched polyimide-silica hybrid membranes. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: [291][292][293][294][295][296][297][298] 2006

Hyperbranched Fluoropolymers and their Hybridization into Complex Amphiphilic Crosslinked Copolymer Networks

“…Furthermore, the incorporation of fluorocarbon increases the hydrophobicity and reduces the surface energy, relative to hydrogenated analogs. HBFPs have been studied as materials for optical waveguide applications, [17] as additives in the cationic photopolymerization of epoxy resins, [19] as corrosion inhibiting coatings, [21] and as membranes for gas separation, [22][23][24] among other applications.…”

Structure-gas Transport Property Relationship of Hyperbranched Polyimide-silica Hybrid Membranes

“…[9][10][11]. In previous researches, we found that the gas permeability and CO 2 /CH 4 selectivity of these membranes prepared via sol-gel reaction using tetramethoxysilane (TMOS) increased with increasing silica content, suggesting the characteristic distribution and interconnectivity of free volume holes created by the incorporation of silica [12][13][14][15][16][17][18].…”

Synthesis and Properties of Hyperbranched Polyimides Combined with Silica

“…Of special interest are polyimidesilica hybrid materials prepared via a sol-gel process for their overall stability and a low coefficient of thermal expansion and water sorption. [3,4] In this work, the preparation, structure and some properties of the series of HBPIsilica hybrid materials, whose polyimide moieties are based on the commercially available 4,4 0 ,4 00 -triaminotriphenylmethane and 4,4 0 -oxydiphthalic anhydride, are studied.…”