Abstract: Elastomeric copolymers of butadiene and piperylene containing at least 50 mole percent butadiene and having a random distribution of monomer units enchained in a stereo-regulated manner are characterized by, (1) vinyl unsaturation pendant to the main polymer chain which is equal to or less than 10 percent of the total unsaturation present in the polymer; (2) enchainment of at least 95 percent of the piperylene as the 1,2-trans and 1,4-trans-stereoisomers; and (3) selective enchainment of between 50 and 95 percent of the butadiene as the 1,4-trans-stereoisomer. The copolymers, which are prepared from a mixture of the monomers with the aid of an iodine-containing hydrocarbon-soluble catalyst system comprising TiX.sub.n --xMI.sub.n --yI.sub.2 --zAlR.sub.3 --QLB, can be compounded with other elastomers and with process oils, resins, plasticizers and reinforcing agents such as carbon black, silica, talc and the like.

Abstract: Non-homogeneous, unvulcanized, paintable elastomeric thermoplastics suitable for use as injection molded automotive decorative and structural parts have been developed. These elastomeric thermoplastic compositions are comprised of a highly crystalline polyolefin, such as polypropylene, a noncrystalline or semicrystalline elastomer and a plasticizer such as a hydrocarbon oil.

Abstract: Blends of 5 to 95 wt. % conjugated diene-containing butyl rubber with 95 to 25 wt. % halobutyl or butyl rubber are capable of higher carbon black loading and have faster cure times, unusually high tensile strength and improved green strength. The blends may be cured with dienophilic compounds or sulfur-based cure packages.

Abstract: Blends of 5 to 95 wt. % conjugated diene-containing butyl rubber with 95 to 5 wt. % halobutyl or butyl rubber are capable of higher carbon black loading and have faster cure times, unusually high tensile strength and improved green strength. The blends may be cured with dienophilic compounds or sulfur-based cure packages.

Abstract: Elastomeric copolymers of butadiene and piperylene containing at least 50 mole percent butadiene and having a random distribution of monomer units enchained in a stereo-regulated manner are characterized by, (1) vinyl unsaturation pendant to the main polymer chain which is equal to or less than 10 percent of the total unsaturation present in the polymer; (2) enchainment of at least 95 percent of the piperylene as the 1,2-trans and 1,4-trans-stereoisomers; and (3) selective enchainment of between 50 and 95 percent of the butadiene as the 1,4-trans-stereoisomer. The copolymers, which are prepared from a mixture of the monomers with the aid of an iodine-containing hydrocarbon-soluble catalyst system comprising TiX.sub.n -xMI.sub.n -yI.sub.2 -zAlR.sub.3 -QLB, can be compounded with other elastomers and with process oils, resins, plasticizers and reinforcing agents such as carbon black, silica, talc and the like.

Abstract: Blends of 5 to 95 wt. % conjugated diene-containing butyl rubber with 95 to 5 wt. % halobutyl or butyl rubber are capable of higher carbon black loading and have faster cure times, unusually high tensile strength and improved green strength. The blends may be cured with dienophilic compounds or sulfur-based cure packages.