Rensselaer Polytechnic Institute

Orion Polymer Corp.

Chulsung Bae

Sangwoo Lee

Woo-Hyung Lee

Eun Joo Park

Sungmin Park

Carrie Lynn Trant

Angela Dee Mohanty

Ding Tian

Sangtaik Noh

Musashi J Briem

Jong Yeob Jeon

Michael Pagels

Junyoung Han

Xiaofeng Wang

Chang Y Ryu

Yu Seung Kim

Bharat Shrimant

Gregory Kline

Santosh Adhikari

An ion exchange membrane material is composed of a crosslinked polymer network including a first poly(styrene-b-ethylene-r-butylene-b-styrene) triblock copolymer (SEBS), and second SEBS, and a linker crosslinking the first SEBS and the second SEBS. At least one phenyl group from the first SEBS and the second SEBS is functionalized with an alkyl group, and the carbon at the benzylic position of these alkyl groups is saturated with at least two additional alkyl groups. The linker is a diamine bound to the alkyl functional groups. The ion exchange membrane material is made via a substantially simultaneous quaternization and crosslinking reaction between the diamine linker and SEBS functionalized with alkyl halide groups. Increasing concentration of crosslinker in produces membranes with reduced water uptake, leading to an expectation of enhanced stability under hydrated conditions and greater durability. Advantageously, this reduction in water uptake came with little change to ion exchange capacity.

Crosslinking of aromatic polymers for anion exchange membranes

Ion exchange membranes for use in electrochemical energy conversion and storage applications include copolymers having a backbone produced from an olefin, such as ethylene, and a cyclic olefin, such as norbornene. Haloalkyl side chains with terminal halide groups are connected to the polymer backbone via Friedel-Crafts alkylation. The halide groups are then replaced with ionic groups via substitution. The ion exchange membrane material can then be cast or impregnated into a reinforcing mesh to form cation exchange membrane or anion exchange membranes. Rigidity of the ion exchange membranes can be controlled by varying the ratio of olefin to cyclic olefin in the polymer backbone.

Preparation of ion exchange membranes from polyolefins and polycyclic olefins

The electrochemical energy conversion system include an anode, a cathode, and a proton exchange membrane disposed between the anode and the cathode. The proton exchange membrane includes a polymer having a hard block polymer, a soft block polymer, and one or more hydrophilic functional groups attached to the soft block polymer. The glass transition temperature of the hard block polymer is higher than a glass transition temperature of the soft block polymer, such that the hard block polymer is non-elastic and the soft block polymer is elastic at a desired operating temperature. The hydrophilic functional groups are attached to the soft block polymer via a thiol-ene reaction to modify double bonds in the soft block polymer. The swellable functional groups are selectively connected to the soft domains of the block copolymers, so that when the membrane swells (under hydration or gas adsorption), the stress is effectively absorbed by the soft domain and the impact on overall mechanical properties is minor, resulting in more durable membranes.

Elastic sulfonated styrene diene block copolymers

The electrochemical energy conversion system of the present disclosure includes an anode, a cathode, and an ion exchange membrane including a polymer having an aromatic polymer chain and an alkylated substrate including an alkyl chain, and at least one ionic group. The alkylated substrate is bound to at least one aromatic group in the polymer chain via Friedel-Crafts alkylation of the at least one aromatic group. The alkylation reaction utilizes a haloalkylated tertiary alcohol or a haloalkylated alkene as a precursor. In the presence of an acid catalyst, a carbocation is generated in the precursor which reacts with the aromatic rings of the polymer chain. The at least one ionic group is then replaced with a desired cationic or anionic group using a substitution reaction. The membranes exhibit advantageous stability achieved through a simplified and scalable reaction scheme.

Ionic functionalization of aromatic polymers for ion exchange membranes

The anion exchange membranes exhibit enhanced chemical stability and ion conductivity when compared with traditional styrene-based alkaline anion exchange membranes. A copolymer backbone is polymerized from a reaction medium that includes a diphenylalkylene and an alkadiene. The copolymer includes a plurality of pendant phenyl groups. The diphenyl groups on the polymer backbone are functionalized with one or more haloalkylated precursor substrates. The terminal halide from the precursor substrate can then be substituted with a desired ionic group. The diphenylethylene-based alkaline anion exchange membranes lack the α-hydrogens sharing tertiary carbons with phenyl groups from polystyrene or styrene-based precursor polymers, resulting in higher chemical stability. The ionic groups are also apart from each other by about 3 to 6 carbons in the polymer backbone, enhancing ion conductivity. These membrane are advantageous for use in fuel cells, electrolyzers employing hydrogen, ion separations, etc.

Alkaline anion exchange membranes derived from diphenylethylene and co-monomer feedstock

Embodiments of the invention relate to a novel class of polymers with superior mechanical properties and chemical stability, as compared to known polymers. These polymers are particularly well suited for use in anion exchange membranes (AEMs), including those employed in fuel cells. Novel methods for the manufacture of these polymers are also described.

Polymers and methods for their manufacture

An anion exchange membrane is composed of a copolymer of 1,1-diphenylethylene and one or more styrene monomers, such as 4-tert-butylstyrene. The copolymer includes a backbone substituted with a plurality of ionic groups coupled to phenyl groups on the backbone via hydrocarbyl tethers between about 1 and about 7 carbons in length. High-temperature conditions enabled by these copolymers enhance conductivity performance, making them particularly suitable for use in anion exchange membranes in fuel cells, electrolyzers employing hydrogen, ion separations, etc. The properties of the membranes can be tuned via the degree of functionalization of the phenyl groups and selection of the functional groups, such as quaternary ammonium groups. Several processes can be used to incorporate the desired ionic functional groups into the polymers, such as chloromethylation, radical bromination, Friedel-Crafts acylation and alkylation, sulfonation followed by amination, or combinations thereof.

Thermally stable hydrocarbon-based anion exchange membrane and ionomers

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.

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Cohoes, NY, United States of America

Chulsung Bae