Functionalized polymer, rubber composition and pneumatic tire
The present invention is directed to a functionalized elastomer comprising the reaction product of a living anionic elastomeric polymer and a polymerization terminator of formula I wherein R 1 , R 2 , R 3 , R 4 , and R 5 are as defined. The invention is further directed to a rubber composition including the functionalized elastomer, and a pneumatic tire including the rubber composition.
1. A functionalized elastomer comprising the reaction product of a living anionic elastomeric polymer and a polymerization terminator of formula I
wherein:
R 1 , R 2 and R 3 are independently C1 to C8 alkyl or C1 to C8 alkoxy with the proviso that at least two of R 1 , R 2 and R 3 are C1 to C8 alkoxy;
R 4 is C1 to C8 alkanediyl, C6 to C8 arylene, C7 to C8 alkylarylene, or C7 to C8 arylalkanediyl; Si is silicon; S is sulfur;
X is —O—R 6 or
wherein O is oxygen; N is nitrogen; and
i) R 5 is —(CH 2 ) 2 —C(═O)— wherein the (CH 2 ) 2 group is adjacent to the sulfur and R 6 and R 7 are independently hydrogen or C1 to C8 alkyl, C6 to C8 aryl, or C7 to C8 arylalkyl; or
ii) R 5 and R 6 taken together with the heteroatom nitrogen or heteroatom oxygen to which both R 5 and R 6 are attached form a 5 membered ring wherein R 5 is —CH—C(═O)— wherein the carbonyl group is adjacent to the heteroatom and R 6 is —CH 2 —C(═O)— wherein the carbonyl group is adjacent to the heteroatom and R 7 is hydrogen or C1 to C8 alkyl, C6 to C8 aryl, or C7 to C8 arylalkyl.
2. The functionalized elastomer of claim 1 , wherein R 1 , R 2 and R 3 are each C1 to C8 alkoxy.
3. The functionalized elastomer of claim 1 , wherein the living anionic elastomer is derived from at least one diene monomer and optionally at least one vinyl aromatic monomer.
4. The functionalized elastomer of claim 1 , wherein the living anionic elastomer is derived from at least one of isoprene and butadiene, and optionally from styrene.
5. The functionalized elastomer of claim 1 , wherein the living anionic elastomer is derived from butadiene and styrene.
6. The functionalized elastomer of claim 1 , wherein the polymerization terminator of formula I is propaneamide, N,N-dimethyl-3-[[3-(triethoxysilyl)propyl]thio]-.
7. The functionalized elastomer of claim 1 , wherein the polymerization terminator of formula I is 2,5-pyrrolidinedione, 1-methyl-3-[[3-(triethoxysilyl)propyl]thio]-.
8. The functionalized elastomer of claim 1 , wherein the polymerization terminator of formula I has the structure
9. The functionalized elastomer of claim 1 , wherein the polymerization terminator of formula I has the structure
10. A rubber composition comprising the functionalized elastomer of claim 1 , and further comprising silica.
11. A pneumatic tire comprising the rubber composition of claim 10 .