Novel grafted nafion membranes for proton‐exchange membrane fuel cell applications

Abstract

Novel poly(glycidyl methacrylate)-grafted Nafion-phosphoric acid membranes for direct-oxidation methanol fuel cells were prepared with a potassium persulfate chemical initiation system for the first time. The introduced epoxy groups were converted to amine groups through a reaction with ethylenediamine, which consequently doped with phosphoric acid (APO 3 H) groups. The latter significantly contributed to enhancing the ionexchange capacity, mechanical properties, and thermal stability. Factors affecting the modification steps were studied. Changes in the chemical and morphological structure were verified through Fourier transform infrared spectroscopy, TGA, and scanning electron microscopy characterization. Various grafting percentages (GP%'s) up to 32.31% were obtained. As a result, the thickness of the grafted membranes increased. Furthermore, the methanol permeability of the modified membranes was reduced with increasing grafted polymer content compared with that of the Nafion membrane. An 83.64% reduction in the methanol permeability was obtained with a polymer grafted content of 18.27%. Finally, the efficiency factor for all of the modified Nafion membranes was enhanced compared with that of Nafion. A fourfold improvement was obtained with membranes with a GP% of 18.27% as a maximum value. Such promising results nominate the used technique as a one for the improvement of Nafion membrane efficiency.

Polymer Electrolyte Membranes Prepared by Graft Copolymerization of 2-Acrylamido-2-Methylpropane Sulfonic Acid and Acrylic Acid on PVDF and ETFE Activated by Electron Beam Treatment

“…Therefore, the operating temperature of the LT-PEM is normally not higher than 100 °C [30,31,32,33]. The Nafion ® membrane is the most commonly used LT-PEM in fuel cells [34,35,36,37,38]. Previously, we reported a different type of polymer electrolyte membranes, which was prepared by activation of ETFE base material with electron beam (EB) treatment, subsequent graft radical copolymerization of methacrylate monomers on ETFE followed by sulfonation to introduce protogenic groups [39,40].…”

Synthesis, optimization, and characterization of poly (Styrene‐co‐Acrylonitrile) copolymer prepared via precipitation polymerization

“…Further increase in the polymerization time had no effect due to the free radicals adsorption on the precipitated polymer particles. Thus, high termination step rate was over the rate of polymerization step . The reaction progress during time caused the initiator and comonomers consumption, decreasing the reaction rate till reaching a constant value at which more time has a negligible effect on the conversion yield.…”

“…[22] While copolymerization between AN with DVB yielded about 80%. [26] The reaction progress during time caused the initiator and comonomers consumption, decreasing the reaction rate till reaching a constant value at which more time has a negligible effect on the conversion yield. [20] So, the conversion yield increased in the sequence: PAN < poly (AN-co-MMA) < poly (St-co-AN) < poly (AN-co-DVB).…”

Bio-Ethanol Production From Environmental Waste Followed by Polymeric Separation of Formed Ethanol/Water Mixture

“…The surface of both CS and SA membranes appear to have a smooth and homogeneous surface and haven't any cracks [19,23]. Ion-exchange capacity indicates the density of ionizable hydrophilic groups in the membrane matrix, which are responsible for the IC of the membranes, and this is an indirect approximation of the proton conductivity [20,[24][25][26][27].IEC results of CS and SA membranes were reported to be 1.54 and 1.04(meq/g), respectively. This result showed that the membranes have good IEC and suitable for using in the separation application technique.…”