Aluminum-substituted phosphotungstic acid/sulfonated poly ether ether ketone nanocomposite membrane with reduced leaching and improved proton conductivity

Abstract

Aluminum-substituted tungstophosphoric acid (AlTPA)/sulfonated poly ether ether ketone (SPEEK) (sulfonation degree approximately 77%) nanocomposite membranes have been prepared for fuel cell application. AlTPA nanoparticles are synthesized by the reaction of TPA and aluminum nitrate in aqueous medium. X-ray diffraction, energy dispersive X-ray, Fourier transform infrared and Raman spectroscopies, and field-emission scanning electron microscopy (FESEM) are used to characterize the AlTPA particles and SPEEK. Study reveals that 2.31 numbers of protons of TPA have been replaced by Al3+ in AlTPA with retention of Keggin’s structure. Nanocomposite membranes with varying AlTPA and TPA content are prepared and evaluated by measuring water uptake, ion exchange capacity, equilibrium water content, water desorption rate, proton conductivity, leaching tendency, and thermal properties. SPEEK/AlTPA nanocomposite membrane exhibits proton conductivity as high as 1.09 mS cm−1 at 10 wt% filler loading. Leaching of filler is reduced by approximately 92% in SPEEK/AlTPA nanocomposite membrane compared to SPEEK/TPA membrane. SPEEK/AlTPA membrane shows approximately 15% higher equilibrium water content and approximately 57% reduction in water desorption rate as compared to SPEEK/TPA membrane. Membranes are thermally stable up to 215°C, which is well above the operating temperature of fuel cells. Composite films are also examined by FESEM to gain further insights into the microstructure.

Poly (ether ether ketone) composites reinforced by graphene oxide and silicon dioxide nanoparticles

“…Commonly used reinforcing materials are as follows: the nanoparticles such as silicon dioxide (SiO 2 ), ZrO 2 , Si 3 N 4 , AlN, and Al 2 O 3 ; fibers such as carbon fiber, steel fiber, and PTFE fiber; whiskers such as potassium carbonate whiskers and zinc oxide whiskers; and so on. 13 –30…”

Thermal, mechanical, and tribological properties of short carbon fibers/PEEK composites

“…[19][20][21] Modification of PEEK with silica, aluminum nitride, graphite, and hydroxyapatite can significantly improve the rigidity and dimensional stability of PEEK at the same time, which can improve the impact resistance and friction resistance of PEEK. [22][23][24][25][26][27][28][29] The blending material of PEEK/PEK has a specific melting point and specific glass transition temperature and excellent formability. 30 The blending system of PEEK/PES keeps the good mechanical properties of PEEK and improves the crystallization properties and flammability of PEEK, and its glass transition temperature is up to 200 C. 31 The blending material of PEEK/PTFE keeps high strength and greater hardness and also has outstanding tribological properties.…”

Direct conversion of furfuryl alcohol to butyl levulinate using tin exchanged tungstophosphoric acid catalysts

“…The Bronsted acidity of TPA is due to the proton conductivity in Keggin structure and exchanging the protons with metal ions results in the presence of both Bronsted as well as Lewis acidity as elucidated previously in literature. [45,46] Exchanging the protons of TPA in its secondary structure improves the proton mobility and thus increases the acidity of prepared catalyst. [46] With exchange of Sn in the secondary structure of TPA will have the same effect and hence results in increase in the acidity of catalyst as explained earlier.…”

“…[45,46] Exchanging the protons of TPA in its secondary structure improves the proton mobility and thus increases the acidity of prepared catalyst. [46] With exchange of Sn in the secondary structure of TPA will have the same effect and hence results in increase in the acidity of catalyst as explained earlier.…”