Functionalized elastomer containing a sulfur group
The present invention is directed to a copolymer of a monomer selected from the group consisting of 1,3-butadiene and isoprene, and a monomer of formula I wherein R 1 is a covalent bond, phenylene, a linear or branched alkane diyl group containing 1 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; and R 2 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms; and X is a sulfur atom or a structure of formula II or III, wherein when X is of formula III, the S atom of formula III is adjacent to the phenyl ring of formula I and the N atom of formula III is adjacent to R1
1. A copolymer of a first monomer selected from the group consisting of 1,3-butadiene and isoprene, and a second monomer of formula I
wherein R 1 is a covalent bond, phenylene, a linear or branched alkane diyl group containing 1 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; and R 2 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms; and X is a sulfur atom or a structure of formula II or III, wherein when X is of formula III, the S atom of formula III is adjacent to the phenyl ring of formula I and the N atom of formula III is adjacent to R1
2. The copolymer of claim 1 , comprising from 0.1 to 40 percent by weight of units derived from the second monomer of formula I based on the weight of the copolymer.
3. The copolymer of claim 1 , comprising from 0.5 to 20 percent by weight of units derived from the second monomer of formula I based on the weight of the copolymer.
4. The copolymer of claim 1 , comprising from 1 to 5 percent by weight of units derived from the second monomer of formula I based on the weight of the copolymer.
5. The copolymer of claim 1 , wherein the monomer of formula I is selected from the group consisting of the following structures:
6. A rubber composition comprising the copolymer of claim 1 .
7. A pneumatic tire comprising the rubber composition of claim 6 .
8. A method of making a copolymer, comprising the step of polymerizing a monomer selected from the group consisting of 1,3-butadiene and isoprene and a monomer of formula I in the presence of an (allyl)(arene)Ni(II) polymerization catalyst
wherein R 1 is a covalent bond, phenylene, a linear or branched alkane diyl group containing 1 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; and R 2 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms; and X is a sulfur atom or a structure of formula II or III, wherein when X is of formula III, the S atom of formula III is adjacent to the phenyl ring of formula I and the N atom of formula III is adjacent to R1
9. The method of claim 8 , wherein the monomer of formula I is selected from the group consisting of the following structures:
10. The method of claim 8 wherein the polymerization catalyst is of formula IV
where BAr F 4 − is tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.