Recently, the fluorine-containing polyimide (PI) materials having high thermal resistance, gas transport, and optical properties have been investigated for development of application.  Especially, there is focused on composite by copolymerization and additive for improving those properties.  Among many additives, polyhedral oligomeric silsesquioxane (POSS) has attracted much attention recently due to their nanometer size, the ease of which these particles can be incorporated into polymeric materials and the unique capability to reinforce polymers.  POSS may be referred to as a silica nanoparticle consisting of a silica cage, as well as other organic functional groups attached to the corners of the cage.  In addition, the composite was synthesized by ABA-type triblock copolymerization.  This method can control the respective component mole ratios in ABA-type triblock copolymer and prevent POSS from cohere with increasing POSS component in the composite.  Therefore, in this study, ABA-type triblock copolymer derived from fluorine-containing polyimide (4,4'-(hexafluoroisopropylidene) diphthalic anhydride-2,3,5,6-tetramethyl-1,4-phenylenediamine (6FDA-TeMPD) macroinitiator with methacryl phenyl POSS (MPPOSS) as organic-inorganic hybrid material was synthesized via atom-transfer radical polymerization.  The respective mole ratios of PI and MPPOSS in ABA-type triblock copolymer (Block(PI/MPPOSS)) were 94/6, 85/15, and 31/69 by determined thermogravimetric analysis.  The Block(PI/MPPOSS) membranes were prepared by casting method with chloroform solution.  The 6FDA-TeMPD membrane, Block(94/6) membrane, and Block(85/15) membrane were self-standing, while Block(31/69) membrane and poly(MPPOSS) membrane had crack and strain.  On the scanning electron microscopy cross-section images, ellipsoidal phase separated structures were observed in Block(PI/MPPOSS) membranes.  The gas permeability coefficients in the Block(94/6) membrane and Block(85/15) membrane decreased compared with 6FDA-TeMPD.  However, the gas permeability coefficient in Block(85/15) was almost the same as Block(94/6).  The gas permselectivity coefficients in Block(94/6) membrane and Block(85/15) membrane increased with only a little amount of POSS.

Synthesis and gas transport properties of ABA-type triblock copolymers derived from fluorine-containing polyimide with POSS by atom transfer radical polymerization

248th National Meeting (2014)

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