ayse merve aslan

ABSTRACT Novel proton conducting nanocomposite membranes included binary and ternary mixtures of acid modified nanotitania particles particles with polymers such as poly (vinyl alcohol) (PVA),pol (vinyl phosphonic acid), sulfonated polysulfone (SPSU) and poly (1-vinyl 1,2,4-triazole) (PVTri) . The interaction of functional nanoparticles with the host matrix were searched by FT-IR spectroscopy. The homogeneous distribution of functional nanoparticles in the membranes was confirmed by SEM micrographs. The spectroscopic measurements and water/methanol uptake studies suggested a complexation between polymers and sulphonic acid that inhibited the leaching out of acidic units. The TGA results verified that the presence of modified nanoparticles in the composite membranes the thermel stability of the membranes enhanced up to above 200 °C.

ABSTRACT Proton conducting nano-composite membranes have been prepared via ternary mixtures comprising sulfated nanotitania (TS), sulfonated polysulfone (SPSU) and nitrilotri(methyl triphosphonic acid) (NMPA). The surface morphology and homogeneity of the composite membranes were searched by scanning electron microscopy (SEM). The existence of ionic interaction between sulfonic acid units in SPSU/TS and phosphonic acid units in NMPA was illustrated in the FT-IR results. The spectroscopic measurements and water uptake studies confirmed the complexation between SPSU/TS and NMPA that inhibited the exclusion of NMPA up on swelling in excess water. The TGA results verified that the membranes are thermally stable up to 270 °C. According to DSC results, the Tg of the materials shifts to lower temperatures with increasing nitrilotri(methyl triphosphonic acid) (NMPA) content. From the methanol permeability experiments it was found that the permeability of the composite membranes is lower than that of commercial Nafion 112. The maximum proton conductivity of SPSU–TS–NMPA is 0.002 S cm− 1 at 150 °C. From the conductivity and spectroscopic results as well as literature data the possible proton conductivity mechanism of the membrane has been modeled.

The development of anhydrous proton conducting membrane is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100–200° C). In the present work, poly (1-vinyl-1, 2, 4-triazole), PVTri was produced by free radical ...

ABSTRACT The synthesis and physicochemical properties of the nanocomposite polymer electrolyte membranes were investigated throughout this work. The materials were prepared via two different approaches where in the first, a binary system was produced by mixing of poly(1-vinyl 1,2,4-triazole) (P(VTri))/sulfated nanotitania (TS) and poly(vinylphosphonic acid) (P(VPA))/sulfated nanotitania (TS) composites. In the second, ternary nano-composite membranes including P(VTri)/TS/P(VPA) were produced at several compositions to get P(VTri)–TS–P(VPA)x where x designates the molar ratio of the polymer repeating units and sulfated nanotitania ratio. The complex structure of the polymers as well as the interaction of functional nano-particles with the matrix were investigated by FT-IR spectroscopy. TGA results verified that the presence of sulfated nanotitania and P(VTri) in the complex polymer electrolytes suppressed the formation of phosphonic acid anhydrides and thermal stability increased up to approximately 300 °C. The DSC results indicate that the Tg of the materials shifts to lower temperatures as P(VPA) content increases. SEM results showed the homogeneity of the nanocomposite membrane systems. Proton conductivity of the membranes was also measured at the anhydrous state. The conductivity of P(VTri)–TSP(VPA)4 is found to be 0.003 (S cm− 1) at 150 °C. The sulfated nanotitania particles in the composite membranes improved the thermal and mechanical properties and enhanced the proton conductivity.

ABSTRACT The synthesis and thermal as well as proton conducting properties of complex polymer electrolytes based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) PAMPS and poly(1-vinyl-1,2,4-triazole) PVTri were investigated. The materials were produced by complexation of PAMPS with PVTri at various compositions to get PVTriP(AMPS) x where x is the molar ratio of the polymer repeating units and varied from 0.25 to 4. The structure of the materials was confirmed by FT-IR spectroscopy. The TGA results verified that the polymer electrolytes are thermally stable up to approximately 200°C. The DSC and SEM results demonstrated the homogeneity of the materials. The electrochemical stability of the materials was studied by cyclic voltammeter (CV). Proton conductivity, activation energy, and water/methanol uptake of these membranes were also measured. After humidification (RH=50%), PVTriP(AMPS)2 and PVTriP(AMPS)4 showed proton conductivities of 0.30 and 0.06S/cm at 100°C, respectively. KeywordsPolymers–Chemical synthesis–Differential scanning calorimetry–Thermogravimetric analysis–Fourier transform infrared spectroscopy–Dielectric properties

We have investigated adenine and guanine functional PGMAAdenine and PGMAGuanine as proton-conducting bioinspired membranes. Poly(glycidyl methacrylate) (PGMA) was prepared by free-radical polymerization and then modified with adenine and guanine molecules via ring opening of the epoxide ring. The complexed structure of the polymers was confirmed by FT-IR spectroscopy and (13)C CP-MAS NMR and elemental analysis studies. The blends of adenine and guanine functional polymers with phosphoric acid (H(3)PO(4)) and poly(vinyl phosphonic acid) (PVPA) were prepared in several stoichiometric ratios. The thermal and proton-conducting properties of these membranes were investigated in the anhydrous state. Phosphoric acid-doped polymers had lower T(g) values and higher proton conductivities than PVPA blends of adenine and guanine functional PGMA. (PGMAAdenine)-(H(3)PO(4))(2) had a maximum water-free proton conductivity of approximately 4 mS/cm at 150 degrees C.

ABSTRACT Throughout this work, the synthesis and characterization of novel proton conducting nanocomposite membranes including binary and ternary mixtures of sulfated nano-titania (TS), poly(vinyl alcohol) (PVA), and nitrilotri(methyl phosphonic acid) (NMPA) are discussed. The materials were produced by means of two different approaches where in the first, PVA and TS (10–15 nm) were admixed to form a binary system. The second method was the ternary nanocomposite membranes including PVA/TS/NMPA that were prepared at several compositions to get PVA–TS–(NMPA)x . The interaction of functional nano particles and NMPA in the host matrix was explored by FT-IR spectroscopy. The homogeneous distribution of bifunctional nanoparticles in the membrane was confirmed by SEM micrographs. The spectroscopic measurements and water/methanol uptake studies suggested a complexation between PVA and NMPA, which inhibited the leaching of the latter. The thermogravimetry analysis results verified that the presence of TS in the composite membranes suppressed the formation of phosphonic acid anhydrides up to 150 °C. The maximum proton conductivity has been measured for PVA–TS–(NMPA)3 as 0.003 S cm−1 at 150 °C.

ABSTRACT A class of polymer electrolyte membranes was produced by the combination of poly(1-vinyl-1,2,4 triazole) (PVTri) and poly(styrene sulfonic acid) (PSSA) at several stoichiometric ratios with respect to the molar ratio of polymer repeating units. PVTri was synthesized by free-radical polymerization of the monomer, 1-vinyl-1,2,4-triazole, and PSSA was produced from polystyrene by direct sulfonation. The proton-exchange reaction, which resulted in complexation between polymers, was illustrated by Fourier transform infrared spectroscopy. Thermogravimetric analysis showed that the membranes are thermally stable up to approximately . The existence of single glass-transition temperatures of the polymer electrolytes was shown by differential scanning calorimetry. The scanning electron microscopy results also demonstrated the homogeneity of the materials. The electrochemical stability of the materials was studied by cyclic voltammetry. Proton conductivities of the anhydrous samples were measured using impedance spectroscopy. Under an anhydrous state, maximum proton conductivities of and membranes were measured as 0.015 at and at , respectively.

... of novel polymer electrolyte membranes (PEMs) with a good mechanical property and high proton conductivity, but with little or no dependence on humidity at higher temperatures (T > 100 °C), remains an important challenge for the commercialization of PEM fuel cells [1 ...