A polymer composition comprising a star-branched copolymer having a plurality of arms is disclosed. Each polymer arm has a molecular weight Mp of from 1 kg/mol to 50 kg/mol and comprises polymerized units (i) derived from a first vinyl aromatic monomer comprising a radical-reactive group, wherein from greater than 10 mol % to 100 mol % of the units (i) are unhydrogenated; and optionally, polymerized units (ii) comprising hydrogenated and unhydrogenated forms of polymerized units derived from a high Tg monomer, and hydrogenated form of polymerized units (i) or hydrogenated form of polymerized styrene units; and optionally, polymerized units (iii) comprising (a) hydrogenated form of polymerized units derived from one or more acyclic conjugated dienes, and (b) polymerized units derived from one or more of a second vinyl aromatic monomer; wherein less than 10 wt. % of units (a) are unhydrogenated.

Disclosed is a copolymer including a first part including an aromatic vinyl-based monomer and a conjugated diene-based monomer; and a second part including an aromatic vinyl-based monomer and a conjugated diene-based monomer, wherein the content of the aromatic vinyl-based monomer is 35 to 45% by weight based on a total weight of the copolymer, and the copolymer satisfies Equation 1 below:
V.sub.1>V.sub.2  <Equation 1> wherein V.sub.1 is a vinyl content in the first part, and V.sub.2 is a vinyl content in the second part.

A styrenic block copolymer having one or more polymer blocks A and one or more polymer blocks B is disclosed, where “A” is a poly(vinylaromatic) block having a molecular weight of greater than 5 kg/mol. The “B” block has a molecular weight of more than 15 kg/mol, and comprises polymerized 1,3-diene units and vinylaromatic units, wherein the polymerized vinylaromatic units represent 5-40 wt. % of the overall weight of the block “B”. The polymerized 1,3-diene units comprise more than 80 wt. % of polymerized isoprene units in which 45-80 mol % are 1,4-isoprene addition units. The blocks “A” and “B” represent from >5 to <40 wt. %, and >33 to <95 wt. %, respectively, relative to the overall weight of the block copolymer. The polymers have physical properties that make them valuable, e.g., as vibration damping materials.

A porous membrane includes a triblock copolymer of the formula ABC. B is a hydrogenated vinyl aromatic block present in a range from 30 to 90 weight percent, based on the total weight of the copolymer and has a T.sub.g of ≥110° C. C is a rubbery block present in a range from 10 to 70 weight percent, based on the total weight of the copolymer and has a T.sub.g≤25° C. A is substantially incompatible with both the B and C blocks and is derived from ring-opening polymerization. B+C is present in a range from 70 to 95 weight percent, based on the total weight of the copolymer.

A binder composition for a non-aqueous secondary battery contains water-soluble macromolecules, water, and a particulate polymer formed of a polymer that includes a block region formed of an aromatic vinyl monomer unit. Surface acid content A of the particulate polymer is 0.05 mmol/g or more, acid content B in an aqueous phase of the binder composition per 1 g of the particulate polymer is not less than 0.03 mmol/g and not more than 0.80 mmol/g, and a ratio (A/B) of the surface acid content A of the particulate polymer and the acid content B in the aqueous phase of the binder composition is not less than 0.5 and not more than 5.0.

A block copolymer composition with a good balance of physical properties suitable for various types of packaging such as food product containers, beverage containers, industrial containers and blister packs, having excellent transparency, gloss, strength, rigidity and formability, having excellent anti-blocking properties and anti-sticking properties, and excelling in the aforementioned properties even when used in mixture with vinyl aromatic hydrocarbon-type polymers is offered. A block copolymer composition of a vinyl aromatic hydrocarbon and a conjugated diene, wherein a block copolymer component (I) having a molecular weight peak in the range of molecular weight 150,000 to 300,000 and comprising tapered blocks has a conjugated diene content of 10 to 20 mass %; a block copolymer component (II) having a molecular weight peak in the range of molecular weight 50,000 to 140,000 and comprising tapered blocks has a conjugated diene content of 30 to 50 mass %; and a ratio (I)/(II) between molecular weight peak areas occupied by block copolymer component (I) and block copolymer component (II) in the block copolymer composition is 20/80 to 80/20.

A styrenic block copolymer is disclosed, having a formula, A-B-A, A-B-B-A, (A-B-A).sub.nX, (A-B).sub.nX or mixtures thereof, wherein n is from 2 to 30, and X is residue of a coupling agent. Each A block is independently a polystyrene having 10-63 wt. % 1,1-diphenylethylene, a GPC peak molecular weight from about 5-40 kg/mol, and forms 10-40 wt. % of the copolymer. Each B block is independently a poly(1,3-diene-co-styrene) comprising: (i) >90 wt. % of polymerized isoprene units relative to the weight of the polymerized 1,3-diene, where S is <40, and (S+V) is 18-75; (ii) >90 wt. % of polymerized butadiene units relative to the weight of the polymerized 1,3-diene, where S is <40, and (1.2*S+V) is 60-120; or combinations thereof “S” represents the polystyrene content, and “V” represents the 1,3-diene content having pendant 1,2- and/or 3,4-vinyl groups in the B block.

The present invention provides a molded bale of a rubber-like block copolymer, satisfying the following requirements 1 to 6: Requirement 1: a content of a vinyl aromatic monomer unit is 9% by mass or more and 50% by mass or less; Requirement 2: a proportion of a vinyl aromatic monomer block is 3% by mass or more and less than 30% by mass; Requirement 3: an iodine value is 3 to 250; Requirement 4: a proportion of an ethylene structure is 3% by mass or more; Requirement 5: a weight average molecular weight is in a range of 80,000 to 1,000,000; and Requirement 6: at least one block at a molecular end is a specific block I or block II.

A viscosity index improver containing a copolymer (A) whose essential constituent monomer is a monomer (a) having a number average molecular weight of 800 to 4,000 represented by the following formula (1), the copolymer (A) having a solubility parameter in the range of 9.00 to 9.40: ##STR00001##
wherein R.sup.1 is a hydrogen atom or a methyl group; —X.sup.1— is a group represented by —O—, —O(AO).sub.m—, or —NH—, AO is a C2-C4 alkyleneoxy group, m is an integer of 1 to 10, each AO may be the same or different when m is 2 or more, and the (AO).sub.m moieties may be randomly bonded or block-bonded; R.sup.2 is a residue after removal of one hydrogen atom from a hydrocarbon polymer whose essential constituent monomer is butadiene in which the butadiene is present in a proportion of 50% by weight or more based on the weight of R.sup.2, or after removal of one hydrogen atom from a polymer formed by partial hydrogenation of the hydrocarbon polymer; and p represents a number of 0 or 1.

A porous membrane includes a triblock copolymer of the formula ABC. B is a hydrogenated vinyl aromatic block present in a range from 30 to 90 weight percent, based on the total weight of the copolymer and has a T.sub.g of 110 C. C is a rubbery block present in a range from 10 to 70 weight percent, based on the total weight of the copolymer and has a T.sub.g25 C. A is substantially incompatible with both the B and C blocks and is derived from ring-opening polymerization. B+C is present in a range from 70 to 95 weight percent, based on the total weight of the copolymer.