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.

Polar modifier systems based on a blend of DTHFP, ETE, TMEDA, DMTHFMA and/or functionally similar compounds with BDMAEE and SMT are used to make block copolymers having high levels of pendant vinyl double bond repeat units, which is through highly selective 1,2-bond butadiene addition, low vinylcyclopentane formation, unimodal narrow molecular weight distribution, and a low level of randomized co-monomer repeat units. The block copolymers have very high levels of 1,2-vinyl content and high 3,4-vinyl bond addition of the conjugated diene monomer and low vinylcyclopentane content. The polar modifier systems provide a fast polymerization rate, with a unimodal narrow molecular weight distribution. The polar modifier systems allow operation at a higher temperature than in prior art systems, which reduces cooling requirements.

The present invention provides a modified diene copolymer composition having a modified A-B-C or C-B-A copolymer comprising at least one conjugated diene monomer and at least one unsubstituted vinyl aromatic monomer and at least one substituted vinyl aromatic monomer, wherein each block or segment in the modified A-B-C or C-B-A copolymer is either a homopolymer or a copolymer comprising at least one conjugated diene monomer and/or at least one unsubstituted vinyl aromatic monomer and/or at least one substituted vinyl aromatic monomer, wherein any of the copolymers have a distribution configuration that is tapered, counter tapered, random or controlled, and wherein any of the homopolymers or the copolymers comprising at least one conjugated diene monomer and/or at least one unsubstituted vinyl aromatic monomer may be in-chain and/or chain-end modified with at least one unit of at least one substituted vinyl aromatic monomer; optionally having a block copolymer made from the modified A-B-C or C-B-A copolymer, wherein the block copolymer comprises at least two of the modified A-B-C or C-B-A copolymers. The invention also provides a process for making the modified diene copolymer composition.

Polar modifier systems based on a blend of DTHFP, ETE, TMEDA, DMTHFMA and/or functionally similar compounds with BDMAEE and SMT are used to make block copolymers having high levels of pendant vinyl double bond repeat units, which is through highly selective 1,2-bond butadiene addition, low vinylcyclopentane formation, unimodal narrow molecular weight distribution, and a low level of randomized co-monomer repeat units. The block copolymers have very high levels of 1,2-vinyl content and high 3,4-vinyl bond addition of the conjugated diene monomer and low vinylcyclopentane content. The polar modifier systems provide a fast polymerization rate, with a unimodal narrow molecular weight distribution. The polar modifier systems allow operation at a higher temperature than in prior art systems, which reduces cooling requirements.

Disclosed herein is a styrenic block copolymer [A1-B1-C1], consisting essentially of polymer blocks A1, B1 and C1. A1 is a poly(para-alkylstyrene) block having a molecular weight from 1,000 to 60,000 g/mol. B1 is a hydrogenated polyisoprene block or a hydrogenated polybutadiene block having a molecular weight from 1,000 to 100,000 g/mol. C1 is a polystyrene block having a molecular weight from 1,000 to 100,000 g/mol; or a polymer block consisting essentially of polymerized styrene units, and hydrogenated butadiene and/or isoprene units, and having a molecular weight from 1,000 to 100,000 g/mol. Prior to hydrogenation, the block B1 has a vinyl content of 5-75 mol %; and the block C1 forms 1-80 wt % of the overall weight of the block copolymer. The selectively sulfonated forms of the copolymers are useful as high dielectric materials.

An embodiment of the present specification provides a method of preparing a copolymer, which includes steps of: (a) adding a polymerization initiator to a monomer mixture including an aromatic vinyl-based monomer, a first conjugated diene-based monomer, and a farnesene monomer to initiate a reaction; and (b) adding a second conjugated diene-based monomer.

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.

Disclosed herein are highly active dilithio initiators prepared from high molecular weight dienes (C≧6) and methods for the preparation of such compounds. These dilithio initiators result in greater control over polymer microstructure and provide useful polymers and oligomers with low vinyl incorporation.

An embodiment of the present specification provides a method of preparing a copolymer, which includes steps of: (a) adding a polymerization initiator to a monomer mixture including an aromatic vinyl-based monomer, a first conjugated diene-based monomer, and a farnesene monomer to initiate a reaction; and (b) adding a second conjugated diene-based monomer.

Provided is a block copolymer that can serve as a precursor of a hydrogenated block copolymer. The block copolymer includes polymer blocks [A] and [B]. The polymer block [A] includes a polycyclic aromatic vinyl monomer unit including at least two monocycles selected from the group consisting of aromatic hydrocarbon monocycles and aromatic heteromonocycles. A mass ratio of proportional content of 1,2-vinyl bonds and proportional content of 1,4-vinyl bonds in the block copolymer is not less than 5/95 and not more than 90/10.