Rensselaer Polytechnic Institute

Orion Polymer Corp.

Ding Tian

Chulsung Bae

Xiaofeng Wang

Chang Y Ryu

Gregory Kline

Santosh Adhikari

Yu Seung Kim

Bharat Shrimant

Eun Joo Park

Ion exchange membranes materials according to the present disclosure exhibit improved conductivity at low and intermediate relative humidity without sacrificing mechanical strength. Polymers are provided that include a backbone with one or more aryl groups, a halocarbyl group, and a halocarbyl side chain attached to the backbone, wherein the halocarbyl side chain includes a halide separated from the backbone by a hydrocarbyl chain, a hydrocarbyl ring, or combinations thereof. The halide is substituted with a tertiary amine and halide anions are then exchanged with hydroxide anions. The polymers are then contacted with phosphoric acid, which is deprotonated by the hydroxide ions, forming anions which enhance interactions with adjacent quaternary ammonium groups and induce excess phosphoric acid molecules to cluster around those quaternary ammonium groups. The membranes exhibit negligible dopant leaching even at high relative humidity.

Phosphate anion-quaternary ammonium ion pair coordinated polymer membranes

Disclosed herein in various embodiments are aryl-ether free polyaromatic polymers based on random copolymer architecture with two, three, or more aromatic ring components and methods of preparing those polymers. The polymers of the present disclosure can be used as ion exchange membranes, e.g., as anion exchange membranes, and ionomer binders in alkaline electrochemical devices.

Quaternized polyaromatics for use in electrochemical devices

An anion exchange membrane is provided by converting carbon-carbon double bonds in the backbone of polystyrene-block-polybutadiene-block-polystyrene (SBS) into epoxide groups. Unmodified SBS is first partially hydrogenated to remove about 65% to about 90% of carbon-carbon double bonds. The remaining double bonds are then converted to epoxide groups to form an epoxidized SBS. UV-initiated ring opening reactions between the epoxidized SBS and haloalkyloxiranes are then employed to simultaneously functionalize and crosslink the epoxidized SBS. The halide groups in the crosslinked polymer network can be replaced via nucleophilic substitution to offer anion conductivity, e.g., via reaction with trimethylamine. Further ion exchange reactions can then be performed to make the membrane hydroxide conductive. The crosslinked membranes described herein exhibit a mechanical strength improvement of 200% compared to unmodified SBS, while maintaining high hydroxide conductivity. This synthetic platform is advantageous to provide mechanically robust anion exchange membranes for fuel cell applications.

Methods of making anion exchange membrane via simultaneous post-functionalization and crosslinking of epoxidized SBS

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Ding Tian