Abstract: A heterogeneous rubbery polymer is provided that includes a polymer chain derived from a vinyl aromatic monomer and a conjugated diolefin monomer, wherein from greater than 20 weight percent to about 40 weight percent of units in the rubbery polymer are derived from the vinyl aromatic monomer and from about 60 weight percent to about 80 weight percent of units in the rubbery polymer are derived from the conjugated diolefin monomer. The polymer chain is further characterized by having greater than zero and less than about 30 weight percent of the vinyl aromatic units in sequences containing 1 vinyl aromatic unit, from about 5 weight percent to about 20 weight percent of the vinyl aromatic units in sequences containing 5 to 8 vinyl aromatic units, and greater than zero and less than about 5 weight percent of the vinyl aromatic units in sequences containing 9 or more vinyl aromatic units.

Abstract: The present invention is directed to a catalyst system for synthesizing rubbery polymers, such as styrene-butadiene rubber, that can be utilized in tire tread rubbers. The catalyst system, in one embodiment, includes an organolithium compound and a potassium alkyl borohydride or potassium alkyl aluminum hydride defined by: (R)3A?(H)K+, wherein A is boron or aluminum, H is hydrogen, K is potassium, and R, which is the same or different, is either H, a C1-C10 alkyl, a C3-C10 cycloalkyl, phenyl, or phenyl substituted C1-C10 alkyl, or a C3-C10 cycloalkyl, with the proviso that at least one R is a C1-C10 alkyl, and further wherein any two R's may optionally be part of a carbocyclic ring. The rubbery polymers can have low to medium vinyl microstructure content, i.e., from about 10% to about 40%, and are useful in tire tread rubber compounds which can exhibit improved wear and tear characteristics.

Abstract: Rubbery polymers can be formed having the general formula: R1R2N—(CH2)n—X—CH2—CHR3R4 wherein R1 and R2 are independently selected from a group consisting of alkyls, cycloalkyls, alkenyls, cycloalkenyls, aryls, phenyls, heterocycles, acyls, and silanes, or R1 in combination with R2 forms a heterocyclic ring; n is an integer from 1 to 20; X is selected from a group consisting of sulfur, a phosphorus moiety, and a silicon moiety; R3 and R4 are one of hydrogen, alkyls, alkenyls, and at least one of which includes reactive unsaturation such as an alkenyl group. Moreover, this invention discloses a process of making functionalized rubbery polymers from the functionalized monomers.

Abstract: This invention relates to the preparation of silica-containing rubber compositions which contain precipitated silica reinforcement and use of an oligomeric organomercaptosilane coupling agent containing a plurality of mercapto and silane moieties, and a minimal content, if any, of ethoxy groups and is thus substantially free of ethoxy groups. The interaction of the plurality of mercapto moieties, or groups, of such oligomeric organomercaptosilane with the diene-based elastomer can promote a significant viscosity build up of the uncured rubber composition in a preliminary non-productive mixing stage and therefore present significant rubber processing difficulties during the mixing of the rubber composition. A challenge is therefore presented for reducing such viscosity buildup for such uncured silica-containing rubber composition.