Sulfonated poly (arylene ether sulfone) proton exchange membranes for fuel cell applications

Abstract

Sulfonated poly (arylene ether sulfone) membranes were synthesized by direct copolymerization of 4,4-bis (4-hydroxyphenyl) valeric acid, 4,4′-difluorodiphenyl sulfone and synthesized sulfonated 6F-bisphenol-A/ bisphenol-A as novel proton exchange membranes for fuel cell applications. Prepared membranes were subsequently crosslinked with synthesized 6F-bisphenol-A based epoxy resin (EFN) by thermal curing reaction keeping in view the resilience and toughness of the membranes. The structural characterization was done by using Fourier transform infrared (FTIR), 1 H nuclear magnetic resonance (NMR) and 13 C NMR techniques. Proton conductivity of the membranes was determined by a four-point probe technique. Methanol permeability was determined by using a diffusion cell in which concentration of the liquids was determined by UV-spectroscopic technique. The enhancement in mechanical properties determined by a universal testing machine and also a better oxidative stability were observed for the crosslinked membranes. However, a decrease in their water and methanol absorption, ion exchange capacity, proton conductivity and methanol permeability was observed. This was due to the reduction in the numbers of ionic channels in case of crosslinked membranes which was confirmed by carrying out morphological analysis of the membranes using atomic force microscopy. In addition, X-ray diffraction measurement by XPERT-PRO diffractometer was also used for structural characterization. Crosslinked membranes showed better thermal stability as determined by thermogravimetric analysis and differential scanning calorimetry.

Layer‐by‐layer Proton Donor and Acceptor Membrane for an Efficient Proton Transfer System in a Polymer Electrolyte Membrane Fuel Cell

“…Aromatic‐based polymers are also good candidates due to their excellent chemical and thermal stability, good mechanical properties, good film forming potential and low cost , . The examples are the sulfonated derivatives of poly(p‐phenylene) , poly(arylene ether sulfone) , , poly(ether sulfone) , poly(ether ketone ketone) and poly(ether ether ketone) (PEEK) , . The sulfonation reaction is an electrophilic substitution, and as a result the electron density is enhanced by the role of sulfonated group .…”

Functionalized carbon nanotube and carbon nanodot modified multiblock poly(arylene ether ketone sulfone) copolymer as proton exchange composite membranes for fuel cell applications

“…The lower water absorption capacity of the polymer main chain is due to the longer block length of the hydrophobic area of the N 2 and N 3 multiblock membranes. The water uptake of the crosslinked copolymer membranes (N 1 , N 2 and N 3 ) was reduced due to the less accessible hydrophilic –COOH groups that participated in the EFN crosslinking reaction 50 . It can be seen from Fig.…”

Hydroquinone based sulfonated poly (arylene ether sulfone) copolymer as proton exchange membrane for fuel cell applications

“…The excess water from the membrane surface was wiped off with the help of filter paper. These membranes were further mounted onto the cell and an alternating current (I) ranging from 0.1-1.0 mA was applied to the cell, while the corresponding voltage (V) was obtained from the nanovoltmeter [30]. The resistance (V/I) was determined from the slope of the linear plot of V vs I, based on the Equations (5) and (6):…”