Abstract: Our invention is directed to a process for producing processable thermoplastic elastomer blends of nitrile rubber with a crystalline polyamide mixture of at least two polyamides at a temperature below the melting temperature of the highest melting polyamide, but above the melting point of the lowest melting polyamide. The amount of nitrile rubber ranges from about 20 to about 80 percent by weight with the polyamides ranging from about 80 to about 20 percent by weight. Although processed at a temperature below the melting point of the highest melting polyamide, usually present in a substantial amount, the compounds surprisingly were readily mixed with the blends being smooth with no loose or fibrous material therein.

Abstract: A method for increasing the primary hydroxyl end groups in polyethers includes the steps of charging a reaction vessel with tetrahydrofuran and propylene oxide, adding BF.sub.3 or a BF.sub.3 -containing catalyst and then polymerizing the first pair of monomers to form a copolymer. After the first copolymerization is at least 60 percent complete, the method further includes the steps of adding ethylene oxide to the copolymer and unreacted monomers in the reaction vessel, and polymerizing the contents therein to form a terpolymer predominantly terminated by primary hydroxyl groups. The reaction is thereafter terminated and the terpolymer is separated from the remaining contents of the reaction vessel, washed and dried. The resulting terpolymer has from about 20 to about 80 weight percent of tetrahydrofuran, from about 10 to about 60 weight percent of propylene oxide, from about five to about 40 weight percent of ethylene oxide and at least 60 mole percent of terminal primary hydroxyl groups.

Abstract: Polyurethanes having a fine particle size are prepared according to a suspension process wherein silicone surfactants are utilized and the polymerization is carried out under agitation in a nonaqueous and a nonsolvent system according to either a two step, or preferably a one step process. The produced suspension-type polyurethanes are generally powders or very small granules and, therefore, can be utilized directly for rotational or spin molding processes wherein they are cured through the use of specific curing agents. Additionally, generally any suspension polyurethanes having a plasticity value of at least 2,000 square mm. at 150.degree. C, can be cured in a rotational or spin molding operation utilizing specific curing agents and curing at a temperature below the decomposition temperature of the polyurethane, for example, below 250.degree. C.

Abstract: The composition disclosed herein involves an oil-extended composition comprising 10-200 parts of oil, preferably 25-125 parts, per 100 parts of a hydrogenated diblock copolymer comprising one block of polybutadiene and one block of a random copolymer of a vinyl arene, such as styrene, and butadiene. This hydrogenated diblock copolymer has improved properties as compared to corresponding hydrogenated random copolymers of the vinyl arene and butadiene, particularly with respect to high temperature properties, oil acceptance and stability against aging.

Abstract: A polyurethane-urea elastomer is prepared by reacting a copolymer of propylene oxide and tetrahydrofuran having hydroxyl end groups with an organic polyisocyanate and the isocyanate-terminated polymer is then reacted with an aromatic diamine in either bulk or solution process.

Abstract: The products disclosed herein involve hydrogenated butadiene-isoprene block copolymers having at least five alternating blocks of the two respective monomers. Such hydrogenated block copolymers have an improved permanent set or lower residual strain as compared to similar hydrogenated block copolymers having only three such alternating blocks. Moreover, a milled product made from such material has a much improved smoothness of surface. These new products are particularly useful in making rubber hose, shoe soles, etc. and are also useful for blending with polyolefins, such as polyethylene, to improve the impact resistance of polyolefin resins without sacrifice of rigidity.

Abstract: Inclusion of 200 - 3000 parts per million of a 1,2-diene in bulk polymerization or copolymerization of 1,3-butadiene with lithium-based catalysts enables the reaction to be carried out in large-size equipment without loss of temperature control.

Abstract: The process disclosed herein involves the preparation of butadiene-styrene copolymers of improved green strength and low running temperature when used in tire compositions, which comprises the steps of polymerizing a mixture of butadiene and styrene in a hydrocarbon solvent having a lithium alkyl initiator therein while the monomer mixture is fed into the polymerization system at a rate slow enough to effect random copolymerization in the resulting polymer backbone, effecting a high degree of branching by conducting the polymerization at a temperature of 90.degree.-175.degree. C. (190.degree.-347.degree. F.) and effecting the final 10-50 percent of the polymerization with a monomer portion containing a higher proportion of styrene than is incorporated into the polymer-backbone, thereby effecting the formation of block polystyrene at the terminals of a plurality of branches. This copolymer of improved green strength and low running temperature is very useful in tire compositions.

Abstract: The process disclosed herein involves the continuous preparation of a multiblock copolymer of two monomers or more such as butadiene and styrene, butadiene and isoprene, etc. This process comprises the alternate feeding of first one monomer stream and then another monomer stream differing in monomer composition from the first monomer stream, each stream of monomer being interrupted while the other stream of monomer is being fed continually into the polymerization system containing an anionic polymerization catalyst capable of polymerizing each of said monomers. A product stream is withdrawn from the polymerization system at the same rate as the total of the feed streams, thereby effecting a continual flow through the polymerization system.