A modified diene elastomer having a good flow resistance, and imparting to a rubber composition containing the same a good compromise of hysteresis and abrasion properties and a satisfactory processing with a view to a tire application is provided. This modified elastomer comprises: a) at least 70% by weight of a linear diene elastomer predominantly functionalized in the middle of the chain by an alkoxysilane group, optionally partly or completely hydrolyzed to silanol, the alkoxysilane group optionally bearing another function capable of interacting with a reinforcing filler, the silicon atom of the alkoxysilane group lying in the main chain of the diene elastomer; b) more than 0 and up to 30% by weight of a star-branched diene elastomer, the Mooney viscosity of said modified diene elastomer varying from 50 to 80 and the glass transition temperature (Tg) thereof varying from 100 C. to 80 C.

The present invention provides a 4-methyl-1-pentene/-olefin copolymer being excellent in lightness, stress absorption, stress relaxation, vibration damping properties, scratch resistance, abrasion resistance, toughness, mechanical properties and flexibility, having no stickiness during molding operation and being excellent in the balance among these properties; a composition comprising the polymer; and uses thereof. The 4-methyl-1-pentene/-olefin copolymer (A) of the present invention satisfies specific requirements, and comprises 5 to 95 mol % of a structural unit (i) derived from 4-methyl-1-pentene, 5 to 95 mol % of a structural unit (ii) derived from at least one kind of -olefin selected from -olefins having 2 to 20 carbon atoms excluding 4-methyl-1-pentene and 0 to 10 mol % of a structural unit (iii) derived from a non-conjugated polyene, provided that the total of the structural units (i), (ii), and (iii) is 100 mol %.

The present invention provides a 4-methyl-1-pentene/-olefin copolymer being excellent in lightness, stress absorption, stress relaxation, vibration damping properties, scratch resistance, abrasion resistance, toughness, mechanical properties and flexibility, having no stickiness during molding operation and being excellent in the balance among these properties; a composition comprising the polymer; and uses thereof. The 4-methyl-1-pentene/-olefin copolymer (A) of the present invention satisfies specific requirements, and comprises 5 to 95 mol % of a structural unit (i) derived from 4-methyl-1-pentene, 5 to 95 mol % of a structural unit (ii) derived from at least one kind of -olefin selected from -olefins having 2 to 20 carbon atoms excluding 4-methyl-1-pentene and 0 to 10 mol % of a structural unit (iii) derived from a non-conjugated polyene, provided that the total of the structural units (i), (ii), and (iii) is 100 mol %.

A heterophasic propylene copolymer (HECO) comprising a polypropylene matrix having a melt flow rate MFR.sub.2 (230 C.) in the range of 40 to 120 g/10 min and a comonomer content in the range of 30 to 75 mol-% for the preparation of molded articles with low CLTE.

A heterophasic propylene copolymer (HECO) comprising a polypropylene matrix having a melt flow rate MFR.sub.2 (230 C.) in the range of 40 to 120 g/10 min and a comonomer content in the range of 30 to 75 mol-% for the preparation of molded articles with low CLTE.

A thermoplastic elastomer composition contains components (A) to (D), wherein the content of the component (A), (B), (C) and (D) is, respectively, 26% by weight or more and 59% by weight or less, 2% by weight or more and 9% by weight or less, 16% by weight or more and 61% by weight or less and 11% by weight or more and 56% by weight or less, when the total amount of the components (A) to (D) is 100% by weight, and the ratio of the content of the component (C) to the content of the component (D) is over 1 and 5 or less.

A process for the synthesis of an ethylene/butadiene copolymer is provided. The process is continuous and comprises:

a. feeding at least one stirred polymerization reactor with a mixture of ethylene, butadiene, hydrocarbon-based solvent and catalytic system allowing the formation of cyclic trans-1,2-cyclohexane units in the polymer chain with a mole ratio of ethylene to the sum of the ethylene and butadiene monomers ranging from 0.5 to 0.99; the concentration of ethylene and butadiene monomers in the polymerization reaction medium being at least 10% by weight relative to the total weight; the operating pressure of the reactor is greater than or equal to the saturated vapour pressure of the polymerization reaction medium;

b. recovering the ethylene/butadiene copolymer, this copolymer comprising, statistically distributed, ethylene units, butadiene units and trans-1,2-cyclohexane units, the molar fraction of ethylene units in the copolymer being greater than or equal to 50%.

A process for the synthesis of an ethylene/butadiene copolymer is provided. The process is continuous and comprises:

a. feeding at least one stirred polymerization reactor with a mixture of ethylene, butadiene, hydrocarbon-based solvent and catalytic system allowing the formation of cyclic trans-1,2-cyclohexane units in the polymer chain with a mole ratio of ethylene to the sum of the ethylene and butadiene monomers ranging from 0.5 to 0.99; the concentration of ethylene and butadiene monomers in the polymerization reaction medium being at least 10% by weight relative to the total weight; the operating pressure of the reactor is greater than or equal to the saturated vapour pressure of the polymerization reaction medium;

b. recovering the ethylene/butadiene copolymer, this copolymer comprising, statistically distributed, ethylene units, butadiene units and trans-1,2-cyclohexane units, the molar fraction of ethylene units in the copolymer being greater than or equal to 50%.

An elastomer is provided, which is a product of reacting C.sub.4-12 lactam, poly(C.sub.2-4 alkylene glycol), C.sub.4-12 diacid, and multi-ester aliphatic monomer. The C.sub.4-12 lactam and the poly(C.sub.2-4 alkylene glycol) have a weight ratio of 20:80 to 80:20. The total weight of the C.sub.4-12 lactam and the poly(C.sub.2-4 alkylene glycol) and the weight of the C.sub.4-12 diacid have a ratio of 100:0.5 to 100:10. The total weight of the C.sub.4-12 lactam and the poly(C.sub.2-4 alkylene glycol) and the weight of the multi-ester aliphatic monomer have a ratio of 100:0.01 to 100:5.

Fluoroelastomer compositions comprising fluoroelastomers having copolymerized units of a nitrile-containing cure site monomer are cured with certain hydrazone or oxime curatives.