Abstract: A branched block copolymer is described, which can be defined by the formula (B.sub.1 -T-A-B.sub.2).sub.n X, where B.sub.1, and B.sub.2 are polydiene blocks, A is an aromatic polyvinyl block, T is a random copolymer segment made up of dienic monomeric and aromatic vinyl units, X is a coupling radical having a valence equal to n, and n is a whole number ranging from 3 to 20. This kind of block copolymer is used in formulations of adhesives having an excellent balance of adhesive, cohesive, rheological characteristics, as well as resistance to heat oxidation, and in compositions together with thermoplastic polymers capable of giving products with improved shock resistance and transparency.

Abstract: A branched block copolymer is described, which can be defined by the formula (B.sub.1 --T--A--B.sub.2).sub.n X, where B.sub.1 and B.sub.2 are polydiene blocks, A is an aromatic polyvinyl block, T is a random copolymer segment made up of dienic monomeric and aromatic vinyl units, X is a coupling radical having a valence equal to n, and n is a whole number ranging from 3 to 20.This kind of block copolymer is used in formulations of adhesives having an excellent balance of adhesive, cohesive, rheological characteristics, as well as resistance to heat oxidation, and in compositions together with thermoplastic polymers capable of giving products with improved shock resistance and transparency.

Abstract: New polymeric compositions comprising:(a) a linear copolymer constituted by four alternating blocks, which can be represented by the formula (I) or (II)B.sub.1 -T-A.sub.1 -B.sub.2 -A.sub.2 (I)orB.sub.1 -A.sub.1 -B.sub.2 -T-A.sub.2 (II)wherein:B.sub.1 and B.sub.2 are polydienic blocks, preferably polybutadienic blocks;A.sub.1 and A.sub.2 are polyvinylaromatic blocks and preferably polystyrenic blocks;T is a portion of random copolymer formed by dienic and vinylaromatic monomer units;(b) a linear copolymer constituted by two blocks, which can be represented by the formulae (III) or (IV)B.sub.3 -T-A.sub.3 (III)orB.sub.3 -A.sub.3 (IV)wherein:B.sub.3 is a polydienic block;A.sub.3 is a polyvinylaromatic block; andT has the above seen meaning.The polymeric composition, which can be blended with polystyrene, can be obtained both by blending the individual components, and by means of novel and original synthesis processes which make it possible both (A) and (B) components to be obtained simultaneously.

Abstract: New polymeric compositions comprising:(a) a linear copolymer constituted by four alternating blocks, which can be represented by the formula (I) or (II)B.sub.1 --T--A.sub.1 --B.sub.2 --A.sub.2 (I)orB.sub.1 --A.sub.1 --B.sub.2 --T--A.sub.2 (II)wherein:B.sub.1 and B.sub.2 are polydienic blocks, preferably polybutadienic blocks;A.sub.1 and A.sub.2 are polyvinylaromatic blocks and preferably polystyrenic blocks;T is a portion of random copolymer formed by dienic and vinylaromatic monomer units;(b) a linear copolymer constituted by two blocks, which can be represented by the formulae (III) or (IV)B.sub.3 --T--A.sub.3 (III)orB.sub.3 --A.sub.3 (IV)wherein:B.sub.3 is a polydienic block;A.sub.3 is a polyvinylaromatic block; andT has the above seen meaning.The polymeric composition, which can be blended with polystyrene, can be obtained both by blending the individual components, and by means of novel and original synthesis processes which make it possible both (A) and (B) components to be obtained simultaneously.

Abstract: Radial and branched block copolymers show a structure: ##STR1## wherein: Z is a radical deriving from a tetrafunctional coupling agent;A is a polystyrene block;B is a polybutadiene blockm, n, p, q are either 1 or zero, with the condition that their sum is comprised within the range of from 1 to 4.Compositions of block copolymers comprise the hereinabove disclosed radial and branched block copolymers, blended with a two-block copolymer B-A, and an "A" homopolymer.The process for the preparation of said radial and branched block copolymers and of the related compositions is disclosed, and furthermore their use is disclosed in bituminous compositions, in order to improve the general characteristics of the bitumens.

Abstract: Linear copolymers with four alternating blocks, represented by the following formula:B.sub.1 -T-A.sub.1 -B.sub.2 -A.sub.2where: A.sub.1 and A.sub.2 are polyvinylaromatic blocks, B.sub.1 and B.sub.2 are blocks consisting of ethylene-butene-1 or ethylene-propylene copolymers, and T is a statistical terpolymer segment formed from ethylene-propylene-vinylarene or ethylene-butene-1-vinylarene monomer units.The copolymers are characterized by a weight-average molecular weight of between 20,000 and 300,000 and a total content of vinylaromatic units of between 10 and 60% by weight. The ratio of the weight-average molecular weight of block A.sub.1 to that of block A.sub.2 is a number between 0.25 and 2.0, and the ratio of the weight-average molecular weight of block B.sub.1 to that of block B.sub.2 is a number between 0.05 and 0.5.

Abstract: A linear copolymer constituted by four alternating blocks:B1-A1-B2-A2wherein:B1 and B2 are polydienic blocks, and preferably polybutadiene blocks, andA1 and A2 are polyvinylaromatic, and preferably polystyrene blocks;which polymer has a weight average molecular weight of from 30,000 to 250,000, and a global content of monomer dienic units of from 40 to 80% by weight, wherein the weight average molecular weight of B1 block is comprised within the range of from 0.1 to 0.5 times the weight average molecular weight of B2 block, and the weight average molecular weight of A1 block is comprised within the range of from 0.25 to 2.0 times the weight average molecular weight of A2 block, and which contains between B1 and A1 blocks a copolymeric moiety formed by randomly linked monomer dienic and vinylaromatic units; is endowed with a desired balance of mechanical characteristics, rheologic characterisatics and characteristics of thermooxidative resistance.The process to prepare such a block copolymer is disclosed.