Details

Autor(en) / Beteiligte

• Bance-Soualhi, Rachida
• Choolaei, Mehdi
• Franklin, Siân A.
• Willson, Terry R.
• Lee, Judy
• Whelligan, Daniel K.
• Crean, C.
• Varcoe, John R.

Titel

Radiation-grafted anion-exchange membranes for reverse electrodialysis: a comparison of N , N , N ′, N ′-tetramethylhexane-1,6-diamine crosslinking (amination stage) and divinylbenzene crosslinking (grafting stage)

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2021-10, Vol.9 (38), p.22025-22038

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Radiation-grafted anion-exchange membranes (RG-AEM) are being developed to evaluate a range of chemistries that have relevance to a variety of electrochemical applications including reverse electrodialysis (RED) salinity gradient power. RG-AEMs are typically fabricated using an electron-beam activated (peroxidated) polymer substrate film. These activated films are first grafted with a monomer, such as vinylbenzyl chloride (VBC) and then reacted with a variety of tertiary amines to yield the desired RG-AEMs. The amination process forms covalently bound quaternary ammonium (QA) head-groups that allow the RG-AEMs to conduct anions such as Cl − . RG-AEMs are of interest as they exhibit high conductivities (100 mS cm −1 at elevated temperatures when containing Cl − anions). However, the current generation of RG-AEMs have two main Achilles' heels: (1) they exhibit low permselectivities; and (2) they exhibit a high degree of swelling in water. Introducing covalent crosslinking into ion-exchange membranes is a well-known strategy to overcome these issues but it often comes with a price – a significantly lowered conductivity (raised in situ resistance). Therefore, the level of crosslinking must be carefully optimised. RG-AEMs can be primarily crosslinked using two methods: (1) introduction of a divinyl monomer into the monomer mixture used during grafting; or (2) introduction of a diamine agent into the amination process. This study looks into both methods where either divinylbenzene (DVB) is added into the grafting mixture or N , N , N ′, N ′-tetramethylhexane-1,6-diamine (TMHDA) is added into the amination mixture. We show that on the balance of two application-relevant properties (resistances in aqueous NaCl (0.5 mol dm −3 ) solution and permselectivity), the diamine crosslinking method is the most effective for RG-AEMs being used in RED cells.