Crosslinked poly (ether ether ketone) hydroxide exchange membranes with improved conductivity

• Published in: Journal of membrane science Vol. 459; pp. 86 - 95
• Main Authors: Wang, Junjun, He, Gaohong, Wu, Xuemei, Yan, Xiaoming, Zhang, Yanpu, Wang, Yongdong, Du, Lin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2014; Elsevier
• Subjects: 1,4-diazabicyclo [2,2,2] octane; Applied sciences; Chemistry; Colloidal state and disperse state; Crosslinking; Ethers; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; General and physical chemistry; Hydroxide conductivity; Hydroxide exchange membrane; Hydroxides; Ion concentration; Ionic mobility; Ketones; Membranes; Polyetheretherketones; Polymer industry, paints, wood; Technology of polymers; Crosslinking; Ion concentration; Hydroxide conductivity; Hydroxide exchange membrane; 1,4-diazabicyclo [2,2,2] octane; Polymeric membrane; Conductivity
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2014.01.068

Crosslinked poly (ether ether ketone) (PEEK) hydroxide exchange membranes are prepared using bi-functional cyclic ammonium, 1,4-diazabicyclo [2,2,2] octane (DABCO), as simultaneous quaternization and crosslinking reagent. Hydroxide conductivity and ion mobility are evaluated as a function of ion concentration, which integrates the counteracting effects of the hydroxide ion amount and crosslinking degree. With the increase of ion concentration, effective mobility of hydroxide ion increases to a high level and then levels off or slightly goes down, suggesting a balance existed between ion concentration and mobility in the crosslinked membranes. As a result, hydroxide conductivity increases rapidly to a high stable level, indicating the applicable range of ion concentration (up to 1.0molL−1) for improving hydroxide conductivity. The crosslinked membranes exhibit high hydroxide conductivity of 33.4mScm−1 at 25°C and low swelling ratio of 48.2% at 60°C. Thermal stability (Tonset: 176°C) of the crosslinked membranes is better as compared with the non-crosslinked (Tonset: 165°C) and trimethylamine quaternized PEEK membranes. •PEEK based HEMs are prepared using DABCO simultaneous quaternization-crosslinking.•Ion concentration–conductivity correlation is proposed to improve conductivity.•CL-QDPEEKOH-149%-50% membrane exhibits high conductivity of 33.4mScm−1 at 25°C.•The crosslinked PEEK HEMs are thermally stable up to 176°C in N2.