BLOCK COPOLYMERS INCLUDING HIGH VINYL SEGMENTS
A method for the preparation of block copolymers including at least one high vinyl segment, the method comprising (i) charging into a reactor a diene monomer in a hydrocarbon solvent, a catalytically effective amount of anionic initiator, and an oligomeric oxolanyl propane, whereby the reactor is optionally cooled; (ii) allowing the diene monomer to polymerize at a peak polymerization temperature of at least about 18° C. and less than about 60° C. to form a first block where the vinyl content is at least about 50 percent by weight; (iii) after step (ii), charging into the reactor a vinyl aromatic monomer, whereby the reactor is optionally heated to a temperature up to about 60° C.; (iv) allowing the vinyl aromatic monomer to polymerize to form a second block; and (v) optionally charging into the reactor a quenching agent.
1 . A block copolymer defined by the formula IV:
d-V O -D-V′-ω (IV)
where V O and V′ are each independently a polyvinyl aromatic block, d and D are each independently a polydiene block, ω is a hydrogen atom, a functional group, or a polymeric segment or block, where d is characterized by a vinyl content of at least 80%, and where d includes less than 160 mer units.
2 . The block copolymer of claim 1 , where the vinyl content of the block copolymer is at least 80%.
3 . The block copolymer of claim 1 , where d is characterized by a vinyl content of at least 85%.
4 . The block copolymer of claim 1 , where each polyvinyl aromatic block derives from the polymerization of vinyl aromatic monomer selected from the group consisting of styrene, α-methyl styrene, p-methylstyrene, and vinylnaphthalene.
5 . The block copolymer of claim 4 , where the vinyl aromatic monomer is styrene.
6 . The block copolymer of claim 1 , where V O includes at least 25 and less than 200 mer units, D includes at least 250 and less than 800 mer units, and V′ includes at least 25 and less than 200 mer units.
7 . The block copolymer of claim 1 , where d includes less than 120 mer units.
8 . The block copolymer of claim 1 , where d derives from the polymerization of 1,3-butadiene.
9 . A block copolymer defined by the formula IV:
d-V O -D-V′-ω (IV)
where V O and V′ are each independently a polyvinyl aromatic block, d and D are each independently a polydiene block, ω is a hydrogen atom, a functional group, or a polymeric segment or block, where d derives from the polymerization of 1,3-butadiene and is characterized by a vinyl content of at least 85%, and where d includes less than 120 mer units, where the vinyl content of the block copolymer is at least 80%.
10 . The block copolymer of claim 9 , where each polyvinyl aromatic block derives from the polymerization of vinyl aromatic monomer selected from the group consisting of styrene, α-methyl styrene, p-methylstyrene, and vinylnaphthalene.
11 . The block copolymer of claim 10 , where the vinyl aromatic monomer is styrene.
12 . A block copolymer defined by the formula IV:
d-V O -D-V′-ω (IV)
where V O and V′ are each independently a polyvinyl aromatic block deriving from the polymerization of styrene, d and D are each independently a polydiene block deriving from the polymerization of styrene 1,3-butadiene, ω is a hydrogen atom, a functional group, or a polymeric segment or block, where d is characterized by a vinyl content of at least 80%, and where d includes less than 160 mer units.
13 . The block copolymer of claim 12 , where the vinyl content of the block copolymer is at least 80%.
14 . The block copolymer of claim 13 , where d is characterized by a vinyl content of at least 85%.
15 . The block copolymer of claim 14 , where d includes less than 120 mer units.