Browsing by Author "Goseki, Raita"

Now showing 1 - 5 of 5

Facile synthesis of multiarmed and multicomponent star polymers by a new iterative methodology using (formyl-protected 1,3-dioxolane)-end-functionalized polymer anions
(2016)
Goseki, Raita
;
Ito, Shotaro
;
Akemine, Emi
;
Hirao, Akira
;
應用化學系
A new and efficient iterative methodology using (formyl-protected 1,3-dioxolane (DOL))-end-functionalized polymer anions was carried out for the facile synthesis of multiarmed and multicomponent mu-star polymers. Using this methodology, both the arm introduction and DOL reintroduction steps are simultaneously performed by the linking reaction of the DOL-end-functionalized polymer anion with the formyl group regenerated from the DOL reintroduced in advance and repeated several times. By combining the DOL-end-functionalized polymer anions with non-DOL-functionalized polymer anions in the linking reaction, synthetically-difficult and well-defined complex mu-star polymers ranging from the ABC, ABCD, ABCDE, and ABCD(2), to the ABCD(2)E(2) types were successfully obtained. Moreover, synthesis of A(3)B(2) and A(3)B(2)C(4) star polymers was also achieved with the same methodology using (DOL)(2)-end-functionalized polymer anions. The arm segments were polystyrene, polystyrene derivatives, polyisoprene, poly(2-vinylpyridine), and poly(alkyl methacrylate(s)), which were introduced into the mu-star polymers via the formyl or alpha-phenylacrylate reaction site(s).
Precise syntheses of structurally possible all tetrablock quaterpolymers by a methodology combining living anionic polymerization with linking chemistry using 1: 1 addition reaction
(2018-02-21)
Goseki, Raita
;
Matsuo, Yuri
;
Hirao, Akira
;
應用化學系
;
Department of Applied Chemistry
A methodology combining living anionic polymerization with linking chemistry using 1 : 1 addition reaction has been developed for the syntheses of tetrablock quaterpolymers composed of A, B, C, and D blocks. With this methodology using the omega-chain-end-(alpha-phenylacrylate (PA))-functionalized D, alpha,omega-chain-end-(2-tetrahydropyranyl ether and PA)-functionalized D, and omega-chain-end-PA-functionalized AD as the building blocks, the following all structurally possible twelve tetrablock quaterpolymers were successfully synthesized: ABCD, ABDC, ACBD, ACDB, ADBC, ADCB, BACD, BADC, BCAD, BDAC, CABD, and CBAD. Polystyrene, poly(2-vinylpyridine), poly(tert-butyl methacrylate) (or poly(methyl methacrylate)), and poly(1,2-butylene oxide) prepared by living anionic polymerization were used as A, B, C, and D blocks, respectively. The polymers synthesized in this study are quite new tetrablock quaterpolymers and well-defined in structure.
Precise Synthesis of Macromolecular Architectures by Novel Iterative Methodology Combining Living Anionic Polymerization with Specially Designed Linking Chemistry
(2017-10-01)
Goseki, Raita
;
Ito, Shotaro
;
Matsuo, Yuri
;
Higashihara, Tomoya
;
Hirao, Akira
This article reviews the development of a novel all-around iterative methodology combining living anionic polymerization with specially designed linking chemistry for macromolecular architecture syntheses. The methodology is designed in such a way that the same reaction site is always regenerated after the polymer chain is introduced in each reaction sequence, and this polymer chain introduction and regeneration of the same reaction site sequence is repeatable. Accordingly, the polymer chain can be successively and, in principle, limitlessly introduced to construct macromolecular architectures. With this iterative methodology, a variety of synthetically difficult macromolecular architectures, i.e., multicomponent -star polymers, high generation dendrimer-like hyperbranched polymers, exactly defined graft polymers, and multiblock polymers having more than three blocks, were successfully synthesized.
Synthesis of multicomponent asymmetric star-branched polymers by iterative methodology with new diblock copolymer in-chain anions as building blocks
(2017-08-25)
Goseki, Raita
;
Ito, Shotaro
;
Hirao, Akira
;
應用化學系
;
Department of Applied Chemistry
New AB diblock copolymer in-chain anions having poly(2-vinylpyridine) (P2VP) and/or poly(methyl methacrylate) (PMMA) blocks, whose anion is located at the junction between the A and B blocks, have been prepared by the 1:1 addition reaction of the living polymer (A) with the omega- or alpha-terminal 1-phenyl1-( 2-pyridinyl) ethylene-functionalized polymer (B). The P2VP-block-PS, PS-block-P2VP, P2VP-blockpoly( 4-tert-butyldimethylsilyloxystyrene), PS-block-PMMA, and P2VP-block-PMMA in-chain anions could be practically prepared for the first time. Based on this preparation, a newly synthesized 1,4-bis(1-(2pyridinyl) ethenyl) benzene satisfactorily works as a key core agent, with which the polymers (A) can be connected to the polymer (B), and the in-chain anion can be generated between the A and B polymers. By developing the iterative methodology with such new block copolymer in-chain anions as the building blocks, the successive synthesis of the 3-arm ABC and 5-arm ABCDE mu-star polymers having PMMA and P2VP arms, which were synthetically difficult by the previous systems, have been successfully achieved. The success of the developed methodology demonstrates the further possibility to synthesize more component mu-star polymers. (C) 2017 Elsevier Ltd. All rights reserved.
Tailored Synthesis of Triblock Co- and Terpolymers Composed of Synthetically Difficult Sequence Orders by Combining Living Anionic Polymerization with Specially Designed Linking Reaction
(2016-03)
Matsuo, Yuri
;
Konno, Ryuji
;
Goseki, Raita
;
Ishizone, Takashi
;
Hirao, Akira
This study demonstrates the versatility and wider applicability of the recently developed methodology combining the living anionic polymerization with a specially designed linking reaction using the alpha-phenylacrylate (or benzyl bromide) function, allowing the synthesis of triblock co- and terpolymers, which are otherwise difficut to be obtained by sequential addition of monomers during a sequential polymerization approach. With this methodology using styrene and four para -substituted styrene derivatives with N-cyclohexylimine, 4-N,N -dimethyl-2-oxazoline, 2,6-di(tert-butyl)-4-methylphenyl ester, and nitrile, 12 polymers among the 16 possible triblock terpolymers and 6 triblock copolymers were successfully synthesized. Furthermore, the synthesis of two tetrablock quarterpolymers was achieved by the same linking methodology. The polymers synthesized in this study are all well-controlled in chain length, composition, which are difficult to be obtained by the sequential polymerization. In addition, they possess functional groups usable for the further modification and introduction of other functionalities.