Synthesis and Characterization of Polymer-Metal Nanostructured Membranes
Technical Report,01 Oct 2011,30 Sep 2015
University of Puerto Rico at Mayaguez Mayaguez Puerto Rico
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Sulfonated polystyrene-isobutylene-styrene SIBS and sulfonated polyether-ether-ketone SPEEK were studied after incorporating metallic counter-ions creating unique polymer-metal nanostructured membranes. A comprehensive materials characterization study was performed to understand their resulting nanostructure and their effect in the transport properties for direct methanol fuel cell DMFC applications and chemical and biological protective clothing CBPC applications. The unique interconnections created by the metallic counter-ions in the ionic domains produced enhanced selectivities for the transport of protons over methanol for DMFC applications and the transport of water over DMMP for CBPC applications. Sulfonated fluoropolymers were also investigated. First the polymer-metal nanostructure of Nafion with several counter-ions was studied upon supercritical fluid CO2 processing. Then, novel fluorinated block copolymers were synthesized using atom transfer radical polymerization ATRP and their resulting nanostructure was analyzed. The polymers synthesized included the following blocks sulfonated polystyrene SPS, poly2,3,4,5,6-pentafluorostyrene P5FS, poly4-fluorostyrene P4FS, and poly2,2,3,4,4,4-hexafluorobutylmethacrylate HEMA. The effect of using different esterified initiators resulted in changes in the thermal properties, electronic configuration and eventually in improved transport properties for DMFC applications. The effect of varying the chemical blocks and their compositions also changed the resulting nanostructure, producing shorter interconnected ionic domains and higher water content, which resulted in the most improved transport properties for DMFC applications. Phase equilibria remain a critical issue for fluorinated polymers, as it can influence free-volume and water content, two important parameters that influence transport properties for the applications pursued.
- Miscellaneous Materials
- Properties of Metals and Alloys
- Polymer Chemistry