Poly(aryl piperidinium) polymers for use as hydroxide exchange membranes and ionomers

A polymer wherein the polymer is one of the following:

• (A) the polymer comprises a reaction product of a polymerization mixture comprising
• (i) a piperidone monomer having the formula:
• or
• a 3-oxo-6-azoniaspiro[5.5]undecane salt monomer having the formula:
• (ii) an aromatic monomer having the formula:
• and
• (iii) optionally, a trifluoroacetophenone monomer having the formula:
• wherein:
• R1 is alkyl, alkenyl, or alkynyl, and the alkyl, alkenyl or alkynyl are optionally substituted with fluoride;
• R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, and R16 are each independently hydrogen, alkyl, alkenyl, or alkynyl, and the alkyl, alkenyl or alkynyl are optionally substituted with fluoride;
• n is 0, 1, 2 or 3;
• and
• X− is an anion;
• or
• (B) the polymer is an anion exchange polymer comprising structural units of Formulae 1A or 2A, 3A, and optionally 4A, wherein the sum of the mole fractions of the structural unit of Formula 1A or 2A and Formulae 4A is equal to the mole fraction of Formulae 3A in the polymer, and the mole ratio of the structural unit of Formula 1A or 2A to the structural unit of Formula 3A is from 0.01 to 1, wherein the structural units of Formulae 1A, 2A, 3A and 4A have the structures:
• wherein:
• R10 are each independently alkyl, alkenyl, or alkynyl, and the alkyl, alkenyl or alkynyl are optionally substituted with fluoride;
• R20, R30, R40, R50, R60, R70, R80, R90, R100, R120, R130, R150, and R160 are each independently hydrogen, alkyl, alkenyl, or alkynyl, and the alkyl, alkenyl or alkynyl are optionally substituted with fluoride;
• n is 0, 1, 2 or 3;
• and
• X− is an anion;
• or
• (C) the polymer is an hydroxide exchange polymer comprising a poly(aryl piperidinium) backbone free of ether linkages, and having water uptake not more than 60% based on the dry weight of the polymer when immersed in pure water at 95° C., or having hydroxide conductivity in pure water at 95° C. of at least 100 mS/cm;
• or
• (D) the polymer is an hydroxide exchange polymer comprising a poly(aryl piperidinium) backbone wherein the polymer (D) has:
• and having:
• a peak power density of at least 350 mW/cm2 when the polymer is used as an hydroxide exchange membrane of an hydroxide exchange membrane fuel cell and is loaded at 20% as an hydroxide exchange ionomer in the cathodic and anodic catalyst layers of the fuel cell, the fuel cell having a 50% Pt/C catalyst and catalyst loading of 0.4 mg Pt/cm2, and test conditions being hydrogen and oxygen flow rates of 0.6 L/min, back pressure of 0.1 MPag, and anode and cathode humidifiers at 95° C. and 98° C., respectively;
• or
• a decrease in voltage over 5.5 hours of operation of not more than 20% and an increase in resistance over 5.5 hours of operation of not more than 20% when the polymer is used as an hydroxide exchange membrane of an hydroxide exchange membrane fuel cell and is loaded at 20% as an hydroxide exchange ionomer in the cathodic and anodic catalyst layers of the fuel cell, the fuel cell having a 50% Pt/C catalyst and catalyst loading of 0.4 mg Pt/cm2, and test conditions being constant current density of 400 mA/cm2, hydrogen and oxygen flow rates of 0.2 L/min, back pressure of 0.05 MPag, and anode and cathode humidifiers at 95° C. and 98° C., respectively.