Anion Exchange Membranes Obtained from Poly(arylene ether sulfone) Block Copolymers Comprising Hydrophilic and Hydrophobic Segments

Abstract

The anion exchange membrane may have different physical and chemical properties, electrochemical performance and mechanical stability depending upon the monomer structure, hydrophilicity and hydrophobic repeating unit, surface form and degree of substitution of functional groups. In current work, poly(arylene ether sulfone) (PAES) block copolymer was created and used as the main chain. After controlling the amount of NBS, the degree of bromination (DB) was changed in Br-PAES. Following that, quaternized PAES (Q-PAES) was synthesized through quaternization. Q-PAES showed a tendency of enhancing water content, expansion rate, ion exchange capacity (IEC) as the degree of substitution of functional groups increased. However, it was confirmed that tensile strength and dimensional properties of membrane reduced while swelling degree was increased. In addition, phase separation of membrane was identified by atomic force microscope (AFM) image, while ionic conductivity is greatly affected by phase separation. The Q-PAES membrane demonstrated a reasonable power output of around 64 mW/cm2 while employed as electrolyte in fuel cell operation.

Enhanced Hydroxide Conductivity and Dimensional Stability with Blended Membranes Containing Hyperbranched PAES/Linear PPO as Anion Exchange Membranes

“…To introduce the hyperbranched structure in the polymer main chain, the hyperbranched hydrophobic HB-PAES-Cl components were synthesized by copolymerization at a molar ratio of THPE/BPS (1.0:2.2) in the presence of K 2 CO 3 as a basic catalyst in an anhydrous system. To optimize the conditions to form the hyperbranched structure of HB-PAES, the polymerization of HB-PAES was conducted under high temperature for a short reaction time to avoid the formation of an undesirable complex network of linear chains, as referred to in a previous report [ 43 ].…”

“…The brominated hyperbranched poly(arylene ether sulfone) (Br-HB-PAES) was synthesized via the Friedel-Crafts alkylation ( Scheme 1 d) [ 41 , 42 , 43 ]. The bromination reaction of Br-HB-PAES was performed with HB-PAES (3.00 g, 0.14 mmol), TCE (30.0 mL), and NBS (4.49 g, 6.30 mmol) as the bromination reagent, with BPO (0.61 g, 0.63 mmol) as the initiator in a two-neck round bottom flask equipped with a reflux condenser under nitrogen flow.…”

Electron-Donating C-NH2 Link Backbone for Highly Alkaline and Mechanical Stable Anion Exchange Membranes

“…By introducing flexible spacers between the cationic groups and polymer backbones, a large variety of side-chain-type AEMs improve ion conductivity and alkaline stability due to the better hydrophilic–hydrophobic microphase separation structure. , As polymer backbones also have great influences on the morphology and properties of AEMs, , numerous studies have focused on novel polymer architectures. Polymer chains with twisted structure , demonstrate additional free volume and rigid microporous structure for hydroxide ion conduction.…”

Diffusion Dialysis for Acid Recovery from Acidic Waste Solutions: Anion Exchange Membranes and Technology Integration

“…AEMs as one kind of ion exchange membranes containing positively charge groups allow the migration of anions and repel cations. In fact, AEMs have already attracted much attention in various areas, such as desalination [ 27 ], alkaline fuel cells [ 28 , 29 , 30 ], wastewater treatment [ 31 , 32 ] and so on. At present, some commercial AEMs, including Selemion DSV (Asahi Glass, Tokyo, Japan), Neosepata AFX/N (Tokuyama Co., Tokyo, Japan) and DF120 (Shandong Tianwei Membrane Technology Co., Weifang, China) series are available for recovering acids.…”