Abstract: The process for the controlled radical (co)polymerization of (meth)acrylic and/or vinyl monomers is characterized in that the bulk, solution, emulsion or suspension polymerization or copolymerization is carried out, at a temperature at which can fall to 0.degree. C., of at least one of the said monomers in the presence of an initiating system comprising a radical-generating compound and at least one catalyst composed of a metal complex containing a ligand of the type?4-R.sup.3 -2,6-(CH.sub.2 NR.sup.1 R.sup.2).sub.2 C.sub.6 H.sub.2 !--(I)in which: R.sup.1 and R.sup.2, which are identical or different, represent a branched or unbranched C.sub.1 -C.sub.4 alkyl group or a phenyl group or alternatively R.sup.1 and R.sup.2 form, with the nitrogen atom to which they are connected, a cyclic amine or alternatively the two R.sup.2 groups, taken together, form a polymethylene bridge and R.sup.3 represents a hydrogen atom, an alkyl or benzyl group or an electron-donating or electron-withdrawing functional group.

Abstract: A multifunctional anionic polymerization initiator which is in the form of a star-shaped polymer, and which is soluble in a nonpolar medium and is substantially free of residual double bonds. The initiator is denoted by the general formula (PA).sub.a N.sup.n- nLi.sup.+. PA is a polymer block of a vinylaromatic or diene monomer A. The variable "a" is the number of branches in the block PA. N is a crosslinked core comprising no or practically no residual double bonds and has the formula (PMc)(RLi).sub.p. Mc is a monomer containing at least two polymerizable double bonds per molecule. PMc is a crosslinked core of at least one polymerized monomer Mc, containing 3 to 30% of residual double bonds in relation to the initial double bonds originating from the monomer Mc. R is an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl. The variable "p" is the number of residual double bonds in PMc which are neutralized by RLi. The variable "n" is the number of anionic sites present in the crosslinked core N.

Abstract: A functionalized elastomer is provided which is of the type containing a substrate elastomer, having a weight-average molecular mass (Mw).sub.0 of between 10,000 and 600,000 daltons and a polydispersity index of less than 5, onto which are grafted, in an amount representing 0.1 to 10% by weight of the substrate, sequences carrying carboxyl or ester functional groups, wherein its weight-average molecular Mw is such that the ratio ##EQU1## is less than 20% and the sequences grafted onto the substrate correspond to the formula ##STR1## in which R.sub.1 denotes an (x+z+1)-valent C.sub.1 to C.sub.12 hydrocarbon radical, X represents H or a monovalent C.sub.1 to C.sub.12 hydrocarbon radical R, z is equal to zero or 1 and x is an integer having a value ranging from 1 to 3 with x+z .ltoreq.3. Bitumen/EF compositions useful for making surfacings may be produced by incorporating the EF into a bituminous component.

Abstract: A multifunctional anionic polymerization initiator which is in the form of a star-shaped polymer, and which is soluble in a nonpolar medium and is substantially free of residual double bonds. The initiator is denoted by the general formula (PA).sub.a N.sup.n- nLi.sup.+. PA is a polymer block of a vinylaromatic or diene monomer A. The variable "a" is the number of branches in the block PA. N is a crosslinked core comprising no or practically no residual double bonds and has the formula (PMc)(RLi).sub.p. Mc is a monomer containing at least two polymerizable double bonds per molecule. PMc is a crosslinked core of at least one polymerized monomer Mc, containing 3 to 30% of residual double bonds in relation to the initial double bonds originating from the monomer Mc. R is an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl. The variable "p" is the number of residual double bonds in PMc which are neutralized by RLi. The variable "n" is the number of anionic sites present in the crosslinked core N.

Abstract: The invention relates to a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3)-B.sub.2 ].sub.m -X-[B.sub.2 (B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents a polyfunctional radical resulting from a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of resulting from vinylaromatic monomer, characterized in that the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer. The invention also relates to the process for obtaining this copolymer.

Abstract: A multifunctional anionic polymerization initiator which is in the form of a star-shaped polymer soluble in an apolar medium and substantially free of residual double bonds. The initiator is denoted by the general formula (PA).sub.a N.sup.n- nLi.sup.+. PA is a polymer block of a vinylaromatic or diene monomer A. The variable "a" is the number of branches in the block PA. N is a crosslinked core comprising no or practically no residual double bonds and has the formula (PMc)(RLi).sub.p. Mc is a monomer containing at least two polymerizable double bonds per molecule. PMc is a crosslinked core of at least one polymerized monomer Mc, containing 3 to 30% of residual double bonds in relation to the initial double bonds originating from the monomer Mc. R is an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl. The variable "p" is the number of residual double bonds in PMc which are neutralized by RLi. The variable "n" is the number of anionic sites present in the crosslinked core N.

Abstract: A process is provided for the preparation of a bitumen-polymer composition which comprises(a) producing at a temperature of between 100.degree. C. and 230.degree. C., a mixture of(i) a bitumen;(ii) a linear block copolymer of styrene and a conjugated diene, the block copolymer being used in a quantity of from 0.5% to 25% by weight of bitumen and having a weight-average molecular weight of between 170,00 and 250,000 and a structure of A-B with A denoting a polymer block consisting of a polystyrene block which may be extended on the B side by a random copolymer of styrene and of the conjugated. diene and B denoting a polymer block consisting of conjugated diene units, and(iii) a coupling agent containing at least one sulphur-donor compound and used in an amount to provide a quantity of sulphur representing, by weight, 0.1% to 10% of the weight of the liner block copolymer of styrene and conjugated diene; and(b) keeping the mixture thus produced at a temperature of between 100.degree. C. and 230.degree. C.

Abstract: The invention relates to a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3)-B.sub.2 ].sub.m -X-[B.sub.2 (B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents a polyfunctional radical resulting from a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of resulting from vinylaromatic monomer, characterized in that the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer. The invention also relates to the process for obtaining this copolymer.

Abstract: A process for manufacturing block copolymers comprising anionically polymerizing a vinyl aromatic hydrocarbon mononer in solution in an aromatic hydrocarbon solvent capable of giving a homogeneous medium until attaining a homogeneous medium with a viscosity greater than 300 Pa.s at 20.degree. C. for a concentration of polymer in the aromatic hydrocarbon solvent between 60 and 90% by weight and then, after introduction of a conjugated diene, carrying out a copolymerization until a homogeneous medium is attained have a viscosity greater than 300 Pa.s at 90.degree. C. for a concentration of copolymer in the aromatic hydrocarbon solvent between 70 and 90% by weight, without the viscosity exceeding 3,000 Pa.s in either of the two polymerization steps.