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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

Although the administration of TM might slightly delay the progression of MCT-induced PH, the physiological significance for treatment is limited, since the survival rate was not improved.