Co-polymerization of an isoolefin with a halogenated co-monomer
View Patent ↗A co-polymer of isobutene and 4-bromo-3-methyl-1-butene formed by direct co-polymerization in a single-step process. A continuous process for forming the co-polymer preferably comprises periodic or semi-continuous addition of catalyst to a mixed monomer solution. Semi-continuous reverse addition of the mixed monomer solution to a pre-provided catalyst solution may also be employed. The co-polymer exhibits allylic bromide functionality and is advantageously curable by either ZnO curing systems or sulfur-based curing systems.
1. A polymer comprising:
a) repeating units derived from at least one isoolefin monomer; and,
b) repeating units derived from a halogenated co-monomer of the formula:
wherein,
R 1 is a C 1 -C 20 alkyl group, a C 2 -C 20 linear or branched olefinic group, or a substituted aromatic hydrocarbon,
R 2 is hydrogen or a C 1 -C 20 alkyl group,
X is bromine or chlorine.
2. The polymer of claim 1 , wherein R 1 is C 1 to C 4 alkyl and wherein R 2 is hydrogen.
3. The polymer of claim 1 , wherein the halogenated co-monomer is 4-bromo-3-methyl-1-butene.
4. The polymer of claim 1 , wherein X is bromine and wherein the polymer comprises at least 0.15 mol % of brominated units.
5. The polymer of claim 1 , wherein X is bromine and wherein the polymer comprises from 2 to 5 mol % of brominated units.
6. The polymer of claim 1 , having a molecular weight (M n ) of from 150 to 500 kg/mol.
7. A cured article made from a polymer according to claim 1 .
8. The cured article of claim 7 , wherein the article is made from the polymer using a zinc oxide curing system.
9. A method of preparing a polymer comprising:
a) providing a mixture of an isoolefin monomer and a halogenated co-monomer of the formula:
wherein,
R 1 is a C 1 -C 20 alkyl group, a C 2 to C 20 linear or branched olefinic group, or a substituted aromatic hydrocarbon,
R 2 is hydrogen or a C 1 -C 20 alkyl group,
X is bromine or chlorine,
dissolved in a polymerization diluent;
b) adding a cationogen initiator in a semi-continuous manner to the mixture; and,
c) reacting the monomers to form the polymer.
10. The method of claim 9 , wherein the catalyst solvent and/or the polymerization diluent is methyl chloride, chloroform or hexane.
11. The method of claim 9 , wherein the semi-continuous addition of the cationogen initiator is in a drop-wise manner.
12. The method of claim 9 , wherein the molar ratio of the isoolefin monomer to the halogenated co-monomer is from 10 to 100.
13. The method of claim 9 , wherein the polymer is made by 1,2 insertion of the halogenated co-monomer in the isoolefin.
14. The method of claim 9 , wherein the conversion is at least 20%.
15. A method of preparing a polymer comprising:
a) providing a solution of a cationogen initiator in a catalyst solvent;
b) adding a mixture of an isoolefin monomer and a halogenated co-monomer of the formula:
wherein,
R 1 is a C 1 -C 20 alkyl group, a C 2 to C 20 linear or branched olefinic group, or a substituted aromatic hydrocarbon,
R 2 is hydrogen or a C 1 -C 20 alkyl group,
X is bromine or chlorine,
dissolved in a polymerization diluent in a semi-continuous manner to the solution; and,
c) reacting the monomers to form the polymer.
16. The method of claim 15 , wherein the catalyst solvent and/or the polymerization diluent is methyl chloride, chloroform or hexane.
17. The method of claim 15 , wherein the semi-continuous addition of the monomer mixture to the cationogen initiator is in a drop-wise manner.
18. The method of claim 15 , wherein the molar ratio of the isoolefin monomer to the halogenated co-monomer is from 10 to 100.
19. The method of claim 15 , wherein the polymer is made by 1,2 insertion of the halogenated co-monomer in the isoolefin.
20. The method of claim 15 , wherein conversion is at least 50%.