Repair of aromatic hydrocarbon-based membranes tested under accelerated fuel cell conditions

A Nature‐Inspired Antioxidant Strategy based on Porphyrin for Aromatic Hydrocarbon Containing Fuel Cell Membranes**

“…Accordingly, we first co‐grafted the monomers α‐methylstyrene (AMS), 2‐methyleneglutaronitrile (MGN) and 4‐vinylbenzyl chloride (VBC) onto electron‐beam irradiated ethylene tetrafluoroethylene (ETFE) sheets (Scheme 2). [36] Where the chloromethyl group of VBC was later used as an anchor point to covalently attach the porphyrin repair agent (Scheme 3). In principle, the protonation of a non‐metalated free base porphyrin could decrease its efficacy to act as a repair agent.…”

“…Therefore, we attempted to measure the relative Cu‐content in the membrane by using two complementary methods, X‐ray fluorescence spectroscopy (XRF) and laser ablation inductively coupled plasma time‐of‐flight mass spectrometry (LA‐ICP‐MS). XRF is generally used to measure metal content in PEMs, [39] while we recently used LA‐ICP‐MS in a study to determine Ce‐content in PEMs [36] . Since no certified polymer reference materials exist, strong matrix effects were expected for the quantification.…”

“…XRF is generally used to measure metal content in PEMs, [39] while we recently used LA-ICP-MS in a study to determine Ce-content in PEMs. [36] Since no certified polymer reference materials exist, strong matrix effects were expected for the quantification. Therefore, both methods represent semi-quantitative approaches, and the concentrations can only be compared relatively and not as absolutes.…”

“…The literature procedure was followed to obtain the monomer analogous model compound, potassium 4-(tert-butyl)-2-methoxyphenylsulfonate (BMPS) that was used in the pulse radiolysis and continuous γ-radiolysis experiments. [36] First, its free acid was synthesized and then was neutralized with 0.05 M KOH to yield the desired potassium salt. Purity of the compound was evaluated using an Agilent 1200 series HPLC system (Agilent, USA) and was found to be > 99 %.…”

“…The VBC amount was measured for AMS/MGN/VBC grafted membranes in our previous work with elemental analysis to be (AMS/MGN/ VBC = 2.7 : 2.9 : 1). [36] A membrane sheet (~800 mg) typically contained around 0.065 mmol of the VBC co-monomer. In a 60 mL glass reactor porphyrin 2 (72 mg, 0.114 mmol, 1.75 eq.)…”