Block copolymers and uses thereof

A polymer composition comprising a star-branched block copolymer having one or more configurations selected from the group consisting of (D-E-)nX, (E-D-)nX, (D-E-D-)nX, (D-F-E-)nX, (D-E-F-)nX, (E-F-D-)nX, and (E-D-F-)nX;

• wherein “n” is an integer from 3 to 50, and X is a coupling agent residue;
• wherein the star-branched block copolymer has a plurality of polymer arms, each polymer arm having a peak molecular weight of from 1 kg/mol to 50 kg/mol, and
• wherein each polymer arm comprises one or more polymer blocks “D” comprising >50 wt. % of polymerized units (i) derived from a first vinyl aromatic monomer, wherein from greater than 10 mol % to 100 mol % of polymerized units (i) are unhydrogenated;
• one or more polymer blocks “E” comprising >50 wt. % of polymerized unit (ii) which comprises
• (a) hydrogenated and unhydrogenated forms of polymerized units derived from a high Tg monomer, and
• (b) hydrogenated form of polymerized units (i) or hydrogenated form of polymerized styrene units;
• and
• optionally one or more polymer blocks “F” comprising >50 wt. % of polymerized unit (iii) which comprises:
• (a) polymerized units derived from one or more acyclic conjugated dienes, wherein less than 10 wt. % of the polymerized units are unhydrogenated;
• and
• (b) polymerized units derived from one or more of a second vinyl aromatic monomer;
• and
• wherein the high Tg monomer is selected from the group consisting of tert-butyl styrene, 1,3 cyclohexadiene, 1,3-cycloheptadiene, benzofulvene, 1,1-diphenylethylene, vinyl biphenyl, adamantyl styrene, vinylanthracene, divinylbenzene, bis(vinylphenyl)ethane, and combinations thereof, and the polymerized units derived from 1,3-cyclohexadiene comprise 1,2-and 1,4-addition units in a relative mole ratio of from 90:10 to 10:90;
• wherein the copolymer contains more than 10 wt. % of polymerized units (i), the polymerized units (i) and (ii) together constitute more than 80 wt. % of the overall weight of the copolymer;
• wherein the copolymer has a peak molecular weight of from 15 kg/mol to 500 kg/mol, and a glass transition temperature of from more than 100° C. to 250° C.;
• wherein the one or more polymer blocks “D” comprise polymerized para-methylstyrene units.