GOALI: Gas Transport and Barrier Properties Aromatic Polyamides

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ABSTRACT CTS-9803225 Benny Freeman/N.C. State U. Proprietary amorphous polyamides used commercially in gas separation applications; liquid crystalline (LC) aromatic polyamides area among the most impermeable barrier polymers available. However, wholly aromatic polyamides in general and LC ones in particular are typically difficult to dissolve and have melting points near or above their decomposition temperatures; melt and solution processing of these materials can be, therefore, quite difficult. Moreover, the synthesis of new higher performance aromatic polyamides can be impeded by their lack of solubility. The proposed experimental research program is a continuation of an earlier two year program to explore the synthesis and gas sorption, transport, and permeation properties of a new class of highly soluble wholly aromatic polyamides, having either rigid rod, possibly mesogenic, backbones or semi-rodlike backbones and structural elements which could be precursors for further reactions such as crosslinking or the attachment of pendent rigid or flexible groups. These fundamental studies are directed toward developing an expanded and more subtle repertoire of structural modification useful for the rational tailoring of super-membranes and super-barriers. Central to the thesis under consideration is the notion that the proposed primary chemical structure variations could markedly influence polymer suprastructure (i.e. polymer chain packing), polymer-pentrant interactions, and, in turn, strongly effect gas sorption, transport, and permeation properties. An Experimental program is proposed involving controlled synthesis of highly soluble wholly aromatic polyamides having substituents which could be used to crosslink the polymers or attach rigid or flexible side chains. The chemical structure, physical properties, and gas transport properties of these polymers would be characterized to determine explicitly the influence of side and main chain molecular architecture and side chain stiffne ss, plus the potential for crosslinking, on the overall sorption, transport, and permeation behavior. ***