Synthesis of heteroarm star‐branched polymers by means of anionic living polymerization

Hirao, Akira; Matsuo, Akira; Morifuji, Kazushi; Tokuda, Yui; Hayashi, Mayumi

doi:10.1002/pat.88

Cited by 26 publications

(15 citation statements)

References 19 publications

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“…In our previous paper, it was observed that the chloromethylated polystyrene was not reacted in THF at -78 8C for 168 h with the living anionic polymer of t BMA prepared by the diphenymethyllithiuminitiated polymerization in the presence of LiCl. [28] On the other hand, the reaction proceeded quantitatively under the same conditions with the living polymer of t BMA prepared by the polymerization with diphenylmethylpotassium. The living anionic polymer of t BMA having potassium counter cation was therefore employed in the reaction with poly(m-halomethylstyrene)s.…”

Section: Synthesis Of Well-defined Graft Copolymers With One Graft Pementioning

confidence: 91%

Synthesis of Branched Polymers by Means of Living Anionic Polymerization, 7. Synthesis of Well-Defined Highly Branched Polymers and Graft Copolymers Having One Branch per Repeating Unit Using Poly(m-halomethylstyrene)s as Backbone Polymers

Ryu

Hirao²

2001

Macromol. Chem. Phys.

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Well‐defined poly(m‐chloromethylstyrene) and poly(m‐bromomethylstyrene) were prepared by the living anionic polymerization of m‐(tert‐butyldimethylsilyl)oxymethylstyrene and subsequent transformation reactions with BCl3 and (CH3)3SiCl/LiBr. The reaction of poly(m‐chloromethylstyrene)s with 1,1‐diphenylethylene (DPE) end‐capped polystyryllithium proceeded very fast in the initial stage (76% of efficiency after 10 min) and reached quantitative reaction efficiency after 24 h at –40°C. The reaction of poly(m‐bromomethylstyrene) with DPE end‐capped polystyryllithium of molecular weight value of up to 68.8 kg/mol proceeded completely without steric hindrance of the polystyrene branch at –40°C for 168 h to afford a very high molecular weight branched polystyrene with one branch per repeating unit (M̄w = 2.3 million). Well‐defined graft copolymers with the same architecture were also successfully synthesized by reacting poly(m‐halomethylstyrene)s with living anionic polymers of isoprene, 2‐vinylpyridine, and tert‐butyl methacrylate at –40°C for 168–336 h. The high compact structures of the branched polystyrenes synthesized here comparable to those of star‐branched polymers were confirmed by viscosity measurement performed in toluene at 35°C.

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Section: Synthesis Of Well-defined Graft Copolymers With One Graft Pementioning

confidence: 91%

Synthesis of Branched Polymers by Means of Living Anionic Polymerization, 7. Synthesis of Well-Defined Highly Branched Polymers and Graft Copolymers Having One Branch per Repeating Unit Using Poly(m-halomethylstyrene)s as Backbone Polymers

Ryu

Hirao²

2001

Macromol. Chem. Phys.

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“…Furthermore, we have recently synthesized a nine-arm AA9 4 A99 4 asymmetric star polystyrene in A 95% yield by using a polystyrene end-functionalized with four CMP groups as illustrated in Scheme 19. [54] The results are summarized in Tab. 10.…”

Section: Synthesis Of Heteroarm Star Polymers Using Cmp Multi-functiomentioning

confidence: 96%

“…[49,50] Furthermore, several regular, asymmetric and heteroarm star polymers were synthesized by using a variety of CMP-functionalized polystyrenes and polystyrene-block-poly(a-methylstyrene)s. The synthesized polymers were stars of the AA9 3 , AA9 4 , AA9A99 2 , AB 3 , AB 4 , A 2 B 4 , A 2 B 12 , ABC 2 , and ABC 4 types where A, B, and C are polystyrene, polyisoprene, and poly(a-methylstyrene), respectively. [49,51,52] Coupling reactions with direct use of poly(styryllithium) or poly(isoprenyllithium) usually proceeded along with the formation (a10%) of star polymers having less arms. This strongly indicates that undesirable side reactions, such as Li1Cl exchange and single-electron transfer reactions, take place during the coupling reactions to a certain extent.…”

Section: Synthesis Of Heteroarm Star Polymers Using Cmp Multi-functiomentioning

confidence: 99%

Synthesis of well-defined functionalized polymers and star branched polymers by means of living anionic polymerization using specially designed 1,1-diphenylethylene derivatives

Hirao¹,

Hayashi

Haraguchi

2000

Macromol. Rapid Commun.

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“…98,111 In these coupling reactions, benzyl bromide functionality is more preferable than the chloride counterpart. The results are summarized in Table IV. Thus, the proposed coupling reaction with use of benzyl halide-functionalized polymers offers a new general and versatile methodology for the synthesis of both regular and star polymers with well-defined architectures.…”

Section: Coupling Reaction Of Living Anionic Polymers With Benzyl Halmentioning

confidence: 99%

“…[95][96][97][98] These benzyl halidefunctionalized polymers are used as polymeric coupling agents in the reaction of living anionic polymers.…”

Section: Synthesis Of Star Polymers Using Benzyl Halide-functionalizementioning

confidence: 99%

Precise Synthesis of Regular and Asymmetric Star Polymers and Densely Branched Polymers with Starlike Structures by Means of Living Anionic Polymerization

Hirao

Hayashi

Tokuda

et al. 2002

Polym J

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ABSTRACT:The subject of this review is to present new synthetic methodologies recently developed by us, which are applicable to both regular and asymmetric star polymers with well-defined architectures. The first methodology involves the coupling reaction of a variety of living anionic polymers of styrene, α-methylstyrene, isoprene, tert-butyl methacrylate, and ethylene oxide with novel chain-end-and in-chain-functionalized polymers with a definite number of benzyl halide moieties intentionally designed as polymeric coupling agents. In the second methodology, we propose a new concept based on iterative approach, with which star polymers can be successively and, in principle, unlimitedly synthesized by repeating the iterative reaction sequence. Finally, a convenient synthesis of densely branched polymers with starlike structures is presented by the quantitative coupling reaction of living anionic polymers with reactive benzyl halide-functionalized backbone polymers based on a grafting-onto method.KEY WORDS Star Polymer / Asymmetric Star Polymer / Living Anionic Polymerization / Iterative Methodology / Polymeric Coupling Agent / 1,1-Diphenylethylene Derivative / Star polymers are branched polymers in which more than three linear polymer chains are linked together at one end of each chain by a central core or a single branch. They have physical properties in bulk, melt, and solution quite distinct from linear analogues. For this reason, star polymers have been widely studied from both synthetic and theoretical points of view. [1][2][3][4][5][6][7][8][9] It is of course essential to use star polymers with welldefined structures for evaluating fundamental understanding regarding the effect of chain branching on such physical properties.At the present time, the most successful methodologies for the synthesis well-defined regular star polymers have been developed mainly based on coupling reactions of living anionic polymers of styrene and 1,3-dinene monomers with multifunctional chlorosilane compounds as electrophilic coupling agents. A variety of star polymers with a definite number of three to eighteen arms have been synthesized. [10][11][12][13][14][15][16][17][18][19] Furthermore, the successful syntheses of the 32-, 64-, and even 128-arm star polymers by using specially designed carbosilane dendrimers have been reported so far. 20,21 Currently, great attention has been paid to more complex asymmetric star polymers whose arms differ in molecular weight and chemical composition, since star polymers of this type are expected to exhibit interesting and unique physical performance originated from their † To whom correspondence should be addressed.branched architectures as well as heterophase structures. [22][23][24][25][26][27][28][29][30][31][32][33] Synthesis of asymmetric star polymers is generally more difficult than that of regular star polymers. In the synthesis of regular star polymers, for example, their arms can be simultaneously introduced by one reaction. On the other hand, two or more highyielding reactions...

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Synthesis of heteroarm star‐branched polymers by means of anionic living polymerization

Cited by 26 publications

References 19 publications

Synthesis of Branched Polymers by Means of Living Anionic Polymerization, 7. Synthesis of Well-Defined Highly Branched Polymers and Graft Copolymers Having One Branch per Repeating Unit Using Poly(m-halomethylstyrene)s as Backbone Polymers

Synthesis of Branched Polymers by Means of Living Anionic Polymerization, 7. Synthesis of Well-Defined Highly Branched Polymers and Graft Copolymers Having One Branch per Repeating Unit Using Poly(m-halomethylstyrene)s as Backbone Polymers

Synthesis of well-defined functionalized polymers and star branched polymers by means of living anionic polymerization using specially designed 1,1-diphenylethylene derivatives

Precise Synthesis of Regular and Asymmetric Star Polymers and Densely Branched Polymers with Starlike Structures by Means of Living Anionic Polymerization

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