Sulfonated block copolymers method for making same, and various uses for such block copolymers
View Patent ↗A sulfonated block copolymer which is solid and non-dispersible in water having at least two polymer end blocks A and at least one polymer interior block B wherein each A block is a polymer containing essentially no sulfonic acid or sulfonate functional groups and each B block is a polymer block containing 10 to 100 mol percent sulfonic acid or sulfonate functional groups based on the number of monomer units of the B block, and wherein said A and B blocks do not contain any significant levels of olefinic unsaturation. Also claimed are processes for making such block copolymers, and the various end uses and applications for such block copolymers.
1. A block copolymer comprising at least two polymer end blocks A, at least one polymer interior block B wherein:
a. each A block is a polymer block containing essentially no sulfonic acid or sulfonate functional groups and each B block is a polymer block containing 10 to 100 mol percent sulfonic acid or sulfonate functional groups based on the number of monomer units of the B block, said A and B blocks containing no significant levels of olefinic unsaturation; and
b. each A block independently having a number average molecular weight between 1,000 and 60,000 and each B block independently having a number average molecular weight between 10,000 and 300,000;
c. each A block being one or more segments of one or more polymerized para-substituted styrene monomers;
d. each B block comprising segments of one or more vinyl aromatic monomers selected from polymerized (i) unsubstituted styrene monomers, (ii) ortho-substituted styrene monomers, (iii) meta-substituted styrene monomers, (iv) alpha-methylstyrene, (v) 1,1-diphenylethylene, (vi) 1,2-diphenylethylene and (vii) mixtures thereof;
e. said B blocks are sulfonated to the extent of 10 to 100 mol percent, based on the units of vinyl aromatic monomer in said B blocks; and
f. the mol percent of vinyl aromatic monomers which are unsubstituted styrene monomers, ortho-substituted styrene monomers, meta-substituted styrene monomers, alpha-methylstyrene, 1,1-diphenylethylene and 1,2-diphenylethylene in each B block being between 10 mol percent and 100 mol percent; and
g. said sulfonated block copolymer is non-dispersible and solid in water, and has a tensile strength greater than 100 psi in the presence of water according to ASTM D412 after immersion in water for 24 hours.
2. The block copolymer according to claim 1 , wherein said A block is a polymer block of para-t-butylstyrene and said B block is a polymer block of unsubstituted styrene.
3. The block copolymer according to claim 1 , wherein said A block is a polymer block of para-methyl styrene and said B block is a polymer block of unsubstituted styrene.
4. The block copolymer according to claim 1 , wherein the interior block B is a hydrogenated copolymer of one or more unsubstituted styrene monomers, and monomers of conjugated dienes having a vinyl content of 20 to 80 mol percent prior to hydrogenation.
5. The block copolymer according to claim 1 , wherein said B block is a random copolymer, a tapered copolymer or a controlled distribution copolymer.
6. The block copolymer according to claim 1 , wherein said D block prior to hydrogenation is polymer block of 1,3-butadiene, and wherein 20 to 80 mol percent of the condensed butadiene units in block D have 1,2-configuration prior to hydrogenation.
7. The block copolymer according to claim 1 , further comprising at least one polymer block D having a glass transition temperature of less than 20° C. and a number average molecular weight of between 1,000 and 50,000.
8. The block copolymer according to claim 1 , having the general configuration A-D-B-D-A, A-B-D-B-A, (A-D-B)nX, (A-B-D)nX, A-B-A, A-B-A-B-A, (A-B-A)nX, or (A-B)nX, or mixtures thereof, where n is an integer from 2 to about 30, and X is coupling agent residue.
9. The block copolymer according to claim 8 , wherein said D block being selected from the group consisting of (i) a polymerized or copolymerized conjugated diene selected from isoprene, 1,3-butadiene having a vinyl content prior to hydrogenation of between 20 and 80 mol percent, (ii) a polymerized acrylate monomer, (iii) a silicon polymer, (iv) polymerized isobutylene and (v) mixtures thereof, wherein any segments containing polymerized 1,3-butadiene or isoprene are subsequently hydrogenated.
10. The block copolymer according to claim 1 , wherein the monomers comprising the B block are selected from the group consisting of sodium p-styrenesulfonate, lithium p-styrenesulfonate, potassium p-styrenesulfonate, ammonium p-styrenesulfonate, amine p-styrenesulfonate, ethyl p-styrenesulfonate, sodium methallylsulfonate, sodium allylsulfonate, sodium vinylsulfonate and mixtures thereof.
11. The block copolymer according to claim 1 , having a water permeability greater than 0.1 times 10 −6 grams per Pascal.meter.hour, according to ASTM E96-00 “desiccant” method, a wet tensile strength greater than 500 psi according to ASTM D412, and a swellability of less than 100% weight after immersion in water for 24 hours.
12. The block copolymer according to claim 1 , having a water permeability greater than 1.0 times 10 −6 grams per Pascal.meter.hour, according to ASTM E96-00 “desiccant” method and a wet tensile strength greater than 1000 psi according to ASTM D412 after immersion in water for 24 hours.
13. The block copolymer according to claim 1 , having a ratio of wet tensile strength to dry tensile strength greater than 0.3.
14. An article formed at least in part from a composition comprising the block copolymer of claim 1 , said article being selected from the group consisting of fuel cells, fabrics, coated fabrics, membranes, filtration membranes, desalination membranes, air conditioning membranes, heat recovery membranes, coatings for membranes, personal hygiene articles, adhesives, hydrogels, antifouling coatings, water absorption articles, electrode assemblies, and marine coatings.