QUATERNIZED STYRENIC BLOCK COPOLYMERS AND METHODS OF PREPARATION THEREOF

1 . A quaternized styrenic block copolymer comprising: a block copolymer selected from a triblock copolymer, a tetrablock copolymer, a pentablock copolymer, and mixtures thereof,

wherein:

the triblock copolymer has a general configuration selected from: A-B-A′, B-A-B, B-A′-B, (A-B)nX, (A′-B)nX, (B-A)nX, (B-A′)nX, and mixtures thereof, wherein each block B is a copolymer block of a vinyl aromatic monomer and a conjugated diene monomer,

the tetrablock copolymer has a general configuration selected from: A-A-B-A, A′-A′-B-A′, A′-A-B-A, A′-A-B-A′, A-A′-B-A′, and mixtures thereof, wherein each block B is a polymer block of a conjugated diene monomer or a copolymer block of a vinyl aromatic monomer and a conjugated diene monomer, and

the pentablock copolymer has a general configuration selected from: A-B-A-B-A, A′-B-A′-B-A′, A′-B-A-B-A, A′-B-A-B-A′, A-B-A′-B-A, B-A-B-A-B, B-A′-B-A′-B, B-A′-B-A-B, (A-B-A′)nX, (A′-B-A)nX, (B-A-B)nX, (B-A′-B)nX, and mixtures thereof, wherein each block B is a polymer block of a conjugated diene monomer or a copolymer block of a vinyl aromatic monomer and a conjugated diene monomer; and

wherein,

n is an integer from 2 to 30,

X is a residue of a coupling agent, and

each block A and A′ is independently a polymer block of a vinyl aromatic monomer, wherein at least one polymerized vinyl aromatic unit in at least one block A and A′ has a general formula (I):

wherein,

R 1 and R 2 independently is a C 1 to C 5 alkyl group,

Z is any of a linear alkyl chain of C 1-12 , a cyclic alkyl chain of C 3-12 , or a branched alkyl chain of C 4-12 ,

QA + is a quaternary ammonium group, and

HL is a counter ion selected from OH − , HCO 3 − , CO 3 2− , F − , Cl − , Br − , and I − .

2 . The quaternized styrenic block copolymer of claim 1 , wherein the quaternized styrenic block copolymer is cross-linked with a cross-linking agent to obtain a cross-linked quaternized styrenic block copolymer.

3 . A film comprising the cross-linked quaternized styrenic block copolymer of claim 2 , wherein the film has a thickness of 0.1 to 500 μm.

4 . The film of claim 3 , wherein the film after aging in 1M KOH solution at 80° C. for 1000 hours, has a reduction in OH − ion conductivity of <50% than OH − ion conductivity of the film before aging, both measured in mS/cm at 80° C.

5 . The film of claim 3 , wherein the film after aging in 1M KOH solution at 80° C. for 10000 hours, has a reduction in OH − ion conductivity of <60% than OH − ion conductivity of the film before aging, both measured in mS/cm at 80° C.

6 . The film of claim 3 , wherein the film after aging in 10 mM K 2 CO 3 solution at 65° C. for 2000 hours, has a reduction in OH ion conductivity of <10% than OH-ion conductivity of the film before aging, both measured in mS/cm at 80° C.

7 . The film of claim 3 , wherein the film after aging in 4M KOH solution at 65° C. for 2000 hours, has a reduction in OH-ion conductivity of <45% than OH − ion conductivity of the film before aging, both measured in mS/cm at 80° C.

8 . The film of claim 3 , wherein the film has a perm-selectivity of >70%, measured using a static membrane potential measurement cell at 25° C.

9 . The film of claim 3 , wherein the film has a resistance (R m+s ) of <2 Ω*cm 2 , measured using LCR resistance meter at 10 kHz.

10 . The film of claim 3 , wherein the film has an ion exchange capacity (IEC) of 1.2 to 3.0 meq/g.

11 . The film of claim 3 , wherein the film has a water uptake of 1 to 10 wt. %, based on total initial weight of the film, in DI water at 80° C. for 24 hours.

12 . The film of claim 3 , wherein the film, in dry condition, has at least one of:

a Young's Modulus of 50 to 2500 MPa;

an elongation at break of 1 to 100%;

a tensile strength of 15 to 40 MPa; and

a toughness of 1 to 8 MJ/m 3 , all are measured according to ASTM D412.

13 . The film of claim 3 , wherein the film after aging in 1M KOH solution at 80° C. for 500 hours, has at least one of:

a Young's modulus of 400 to 700 MPa;

an elongation at break of 1 to 20%;

a tensile strength of 5 to 20 MPa; and

a toughness of 1 to 5 MJ/m 3 ; all are measured according to ASTM D412.

14 . The quaternized styrenic block copolymer of claim 1 , wherein when the block B is a copolymer block of a vinyl aromatic monomer and a conjugated diene monomer, wherein the block B has a weight ratio of the polymerized vinyl aromatic monomer to the polymerized conjugated diene monomer of >1.

15 . The quaternized styrenic block copolymer of claim 1 , wherein the quaternized styrenic block copolymer is obtained by halogenation and quaternization of a styrenic block copolymer precursor, and wherein quaternization is performed by using at least one quaternizing agent selected from the group consisting of dimethyl amine, trimethyl amine, 1-methyl piperidine, 1-methylimidazole, 1,2-dimethylimidazole, 2,4-dimethylimidazole, N-methylmorpholine, 3-hydroxypropyldimethylamine, n-butyldimethylamine, di(3-hydroxypropyl)methylamine, 2,3-dihydroxypropyldimethylamine, 3-hydroxypropyldiethylamine, 2-hydroxypropyldimethylamine, 4-hydroxybutyldimethylamine, 2-hydroxyethyldimethylamine, n-propyldimethylamine, 2-hydroxyethoxyethyldimethylamine, di(2-hydroxyethyl)methylamine, benzyldimethylamine and 4-hydroxybenzyldimethylamine, 3-ethylpyridine, 4-propylpyridine, 4-tertbutylpyridine, 4-cyanopyridine, 4-isopropylpyridine, 4-methoxypyridine, 3,4-lutidine, 3-methoxypyridine, 4-pyridinemethanol, N,N,N,N-tetramethyl hexyl diamine, and mixtures thereof.

16 . The quaternized styrenic block copolymer of claim 2 , wherein the cross-linking agent is a polyamine represented by a general formula II:

(R 5 ) 2 N—(CH 2 ) t —N(R 5 ) 2   (II)

wherein t=1 to 7; and R 5 is independently a H atom, a C 1-5 alkyl group, or a C 1-5 hydroxyalkyl group.

17 . The quaternized styrenic block copolymer of claim 1 , wherein at least one block A and A′ independently comprises a polystyrene block containing at least one quaternary ammonium group.

18 . The quaternized styrenic block copolymer of claim 1 , wherein:

the vinyl aromatic monomer is selected from the group consisting of styrene, para-substituted styrene, ortho-substituted styrene, meta-substituted styrene, alpha-methylstyrene, 1,1-diphenylethylene, 1,2-diphenylethylene, and mixtures thereof; and

the conjugated diene monomer is selected from the group consisting of isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 3-butyl-1,3-octadiene, farnesene, myrcene, piperylene, cyclohexadiene, and mixtures thereof.

19 . The quaternized styrenic block copolymer of claim 1 , wherein each block A and A′ independently has a molecular weight (M p ) of 3 to 100 kg/mol;

wherein the block B has a molecular weight (M p ) of 2 to 150 kg/mol, when the block B is a polymer block of a conjugated diene monomer; and

wherein the block B has a molecular weight (M p ) of 30 to 150 kg/mol, when the block B is a copolymer block of a conjugated diene monomer and a vinyl aromatic monomer.

20 . An anion exchange membrane (AEM) comprising the cross-linked quaternized styrenic block copolymer of claim 2 .