Preparation and characterization of novel basic polysulfone polymers

Kerres, Jochen; Ullrich, A.; Hein, M.

doi:10.1002/pola.1267

Cited by 55 publications

(52 citation statements)

References 18 publications

(21 reference statements)

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“…A likely reason for the lower than expected DS is steric hindrance of the electrophilic around the sulfone linkage because the electrophilic carbon center is not easily accessible. 46 Another reason could be side reactions.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…In our work on polysulfone modification by lithiation, [7][8][9][10][11]46 we and others have demonstrated that this synthetic method is an effective approach to postfunctionalized PSf with a wide variety of functional groups. Reaction of various electrophilic aryl and alkyl carbonyl compounds with PSf-Li yields the corresponding carbinol substituents, 9−11 including those containing arylamines.…”

Section: ■ Introductionmentioning

confidence: 99%

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Phenyltrimethylammonium Functionalized Polysulfone Anion Exchange Membranes

et al. 2012

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Anion exchange membrane (AEM) materials were prepared from commercial polysulfone (PSf) by functionalization with tertiary amines via lithiation chemistry. By optimizing the reaction conditions, a degree of substitution (DS) of 0.81 could be achieved without evident polymer decomposition or cross-linking. The PSf containing pendent bis(phenyldimethylamine) substituents were then quaternized with CH3I and ion exchange reaction to provide bis(phenyltrimethylammonium) (PTMA) polymer with hydroxide-conductive properties. Flexible and tough membranes with various ion exchange capacities (IEC)s could be prepared by casting the polymers from DMAc solutions. The ionomeric membranes showed considerably lower water uptake (less than 20%), and thus dimensional swelling in water, compared with many reported AEMs. The hydroxide conductivities of the membranes were above 10 mS/cm at room temperature. The unusually low water uptake and good hydroxide conductivity may be attributed to the “side-chain-type” structures of pendent functional groups, which facilitate ion transport. Although the PTMA substituents on the AEM were found to have insufficient long-term stability for alkaline fuel cell application, the investigation gives some insight and directions for polymeric designs by postfunctionalization.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Phenyltrimethylammonium Functionalized Polysulfone Anion Exchange Membranes

et al. 2012

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“…Basic polymers are typically PBI, but other polymers such as poly(4-vinylpyridine) (P 4 VP) [143], aminated PSF [144,145] and PEEK [146] and pyridine containing polymers [91,92] have also been used. The acidic polymers are typically sulphonated polysulphone (SPSF) [147,148], sulphonated polyetheretherketone (SPEEK) [149], sulphonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO [150]), sulphonated poly(arylene thioether)s [151], and sulphonated poly[bis(phenoxy)phosphazene] (SPOP [152]).…”

Section: Ionic Cross-linkingmentioning

confidence: 99%

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

Jensen

Savinell

et al. 2009

Progress in Polymer Science

1,235

852

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. To achieve high temperature operation of proton exchange membrane fuel cells (PEMFC), preferably under ambient pressure, acid-base polymer membranes represent an effective approach. The phosphoric acid-doped polybenzimidazole membrane seems so far the most successful system in the field. It has in recent years motivated extensive research activities with great progress. This treatise is devoted to updating the development, covering polymer synthesis, membrane casting, physicochemical characterizations and fuel cell technologies. To optimize the membrane properties, high molecular weight polymers with synthetically modified or N-substituted structures have been synthesized. Techniques for membrane casting from organic solutions and directly from acid solutions have been developed. Ionic and covalent cross-linking as well as inorganic-organic composites has been explored. Membrane characterizations have been made including spectroscopy, water uptake and acid doping, thermal and oxidative stability, conductivity, electro-osmotic water drag, methanol crossover, solubility and permeability of gases, and oxygen reduction kinetics. Related fuel cell technologies such as electrode and MEA fabrication have been developed and high temperature PEMFC has been successfully demonstrated at temperatures of up to 200• C under ambient pressure. No gas humidification is mandatory, which enables the elimination of the complicated humidification system, compared with Nafion cells. Other operating features of the PBI cell include easy control of air flow rate, cell temperature and cooling. The PBI cell operating at above 150• C can tolerate up to 1% CO and 10 ppm SO 2 in the fuel stream, allowing for simplification of the fuel processing system and possible integration of the fuel cell stack with fuel processing units. Long-term durability with a degradation rate of 5 V h −1 has been achieved under continuous operation with hydrogen and air at 150-160• C. With load or thermal cycling, a performance loss of 300 V per cycle or 40 V h −1 per operating hour was observed. Further improvement should be done by, e.g. optimizing the thermal and chemical stability of the polymer, acid-base interaction and acid management, activity and stability of catalyst and more importantly the catalyst support, as well as the integral interface between electrode and membrane.

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“…proton channels 22 and pumps 23 ), carbon nanotubes, 24 and PEMs. [25][26][27][28][29][30][31][32] Clearly, an understanding of both the common (i.e. in the formation of a continuous network of dynamical hydrogen bonds and the excess protonic charge following the center of symmetry of the hydrogen bond coordination) and distinct features in the molecular details of proton movement in these systems will prove helpful in the development of highly conductive PEMs.…”

Section: Introductionmentioning

confidence: 99%

Molecular Modeling of the Short-Side-Chain Perfluorosulfonic Acid Membrane

2005

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Presented here is a first principles based molecular modeling investigation of the possible role of the side chain in effecting proton transfer in the short-side-chain perfluorosulfonic acid fuel cell membrane under minimal hydration conditions. Extensive searches for the global minimum energy structures of fragments of the polymer having two pendant side chains of distinct separation (with chemical formula: CF 3 CF(O(CF 2 ) 2 -SO 3 H)(CF 2 ) n CF(O(CF 2 ) 2 SO 3 H)CF 3 , where n ) 5, 7, and 9) with and without explicit water molecules have shown that the side chain separation influences both the extent and nature of the hydrogen bonding between the terminal sulfonic acid groups and the number of water molecules required to transfer the proton to the water molecules of the first hydration shell. Specifically, we have found that fully optimized structures at the B3LYP/6-311G** level revealed that the number of water molecules needed to connect the sulfonic acid groups scaled as a function of the number of fluoromethylene groups in the backbone, with one, two, and three water molecules required to connect the sulfonic acid groups in fragments with n ) 5, 7, and 9, respectively. With the addition of explicit water molecules to each of the polymeric fragments, we found that the minimum number of water molecules required to effect proton transfer also increases as the number of separating tetrafluoroethylene units in the backbone is increased. Furthermore, calculation of water binding energies on CP-corrected potential energy surfaces showed that the water molecules bound more strongly after proton dissociation had occurred from the terminal sulfonic acid groups independent of the degree of separation of the side chains. Our calculations provide a baseline for molecular results that can be used to assess the impact of changes of polymer chemistry on proton conduction, including the side chain length and acidic functional group.

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Preparation and characterization of novel basic polysulfone polymers

Cited by 55 publications

References 18 publications

Phenyltrimethylammonium Functionalized Polysulfone Anion Exchange Membranes

Phenyltrimethylammonium Functionalized Polysulfone Anion Exchange Membranes

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

Molecular Modeling of the Short-Side-Chain Perfluorosulfonic Acid Membrane

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