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Shohei Ida Takaya Terashima Makoto Ouchi Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2010,48(15):3375-3381
Amine‐functionalized and amine‐carboxylate double‐functionalized polymers ( I and II , respectively) have been synthesized by a selective single addition of a protected 2‐aminoethyl vinyl ether (BocVE) {CH2 = CH[OCH2CH2N(Boc)2]; Boc = t‐butoxycarbonyl} onto a living cationic poly(n‐butyl vinyl ether) [poly(NBVE)] initiated with the SnCl4/n‐Bu4NCl system: ( I ) ‐(NBVE)n‐ CH2CH(OCH2CH2NH2)‐H; ( II ) ‐(NBVE)n‐CH2CH(OCH2CH2NH2)‐CH2CO2H. The single addition was examined with a set of alkene monomers less reactive than NBVE, including BocVE, 2‐chloroethyl vinyl ether, 2‐vinyloxyethylphtalimide, and styrene (St). Upon addition of 10 molar excess of these alkenes onto the living ends, only BocVE led to the intended single adduct, and this was attributed to a chelating interaction of the two carboxylate groups in the terminal BocVE unit with the growing poly(NBVE) terminal, thus sterically hampering further propagation. A simple acid‐catalyzed Boc‐deprotection led to the amino‐functionalized version I . Alternatively, an additional quenching the BocVE‐capped living end (the precursor of I ) with sodium malonate, followed by double deprotection of the Boc and the malonate groups gave the double‐functionalized version II . The selective addition of a single monomer molecule is thus a new method for addressable or site‐specific introduction of functional groups along polymer chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3375–3381, 2010 相似文献
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Mayuka Yamada Tomoya Yoshizaki Arihiro Kanazawa Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2019,57(21):2166-2174
This article describes the syntheses of various functional star‐shaped polymers via monomer‐selective living cationic polymerization of a vinyl ether (VE) and a divinyl compound with alkoxystyrene moieties by a one‐shot method. An aqueous solution of the resulting star‐shaped polymers with oxyethylene pendants exhibits thermally induced phase separation behavior. To achieve domino synthesis from various monomers, we investigated the optimum reactivity difference using a functional VE and a monofunctional alkoxystyrene. Moreover, the one‐shot copolymerization of a bifunctional VE and an alkoxystyrene is also conducted to yield a star‐shaped polymer via the core‐first method. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2166–2174 相似文献
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Hiroaki Shimomoto Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4137-4144
A series of poly(2‐methoxyethyl vinyl ether)s with narrow molecular weight distributions and with perfectly defined end groups of varying hydrophobicities was successfully synthesized by base‐assisting living cationic polymerization. The end group was shown to greatly affect the temperature‐induced phase separation behavior of aqueous solutions (lower critical solution temperature‐type phase separation) or organic solutions (upper critical solution temperature‐type phase separation) of the polymers. The cloud points were also influenced largely by the molecular weight and concentration of the polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Kazuhiro Nakatani Makoto Ouchi Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2009,47(16):4194-4201
We employed alcohols as initiators for living cationic polymerization of vinyl ethers and p‐methoxystyrene, coupled with tolerant Lewis acid, borontrifluoride etherate (BF3OEt2), although they were known to be poisonous reagent to bring about chain‐breaking such as chain transfer/termination rather than such beneficial one for propagation and polymerization‐control. As well known, without assistance of additive, ill‐defined polymers with broad molecular weight distributions (MWDs) were produced. Even addition of conventional oxygen‐based bases, for example, ethyl acetate (AcOEt), 1,4‐dioxane (DO), tetrahydrofran (THF), and diethyl ether (Et2O) was less efficient in this system to control molecular weights and MWDs (Mw/Mn > 2.0). In contrast, by addition of dimethyl sulfide (Me2S), MWDs of the resultant polymers became much narrower (Mw/Mn < 1.23) and the number‐average molecular weight (Mn) increased in direct proportion to monomer conversion in agreement with the calculated values assuming that one alcohol molecule generates one polymer chain. Studying changed feed‐ratio of alcohol to monomer and structural analyses with NMR and MALDI‐TOF‐MS indicated that quantitative initiation from alcohol giving alkoxide counteranion. This system opens a new way to use a variety of alcohols as initiators, which would allow us to design variety of structures and functions of counteranion. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4194–4201, 2009 相似文献
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Motomasa Yonezumi Nanako Takano Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(20):6746-6753
A quite small dose of a poisonous species was found to induce living cationic polymerization of isobutyl vinyl ether (IBVE) in toluene at 0 °C. In the presence of a small amount of N,N‐dimethylacetamide, living cationic polymerization of IBVE was achieved using SnCl4, producing a low polydispersity polymer (weight–average molecular weight/number–average molecular weight (Mw/Mn) ≤ 1.1), whereas the polymerization was terminated at its higher concentration. In addition, amine derivatives (common terminators) as stronger bases allow living polymerization when a catalytic quantity was used. On the other hand, EtAlCl2 produced polymers with comparatively broad MWDs (Mw/Mn ～ 2), although the polymerization was slightly retarded. The systems with a strong base required much less quantity of bases than weak base systems such as ethers or esters for living polymerization. The strong base system exhibited Lewis acid preference: living polymerization proceeded only with SnCl4, TiCl4, or ZnCl2, whereas a range of Lewis acids are effective for achieving living polymerization in the conventional weak base system such as an ester and an ether. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6746–6753, 2008 相似文献
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Motomasa Yonezumi Satoshi Okumoto Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(18):6129-6141
Living cationic copolymerization of amide‐functional vinyl ethers with isobutyl vinyl ether (IBVE) was achieved using SnCl4 in the presence of ethyl acetate at 0 °C: the number–average molecular weight of the obtained polymers increased in direct proportion to the monomer conversion with relatively low polydispersity, and the amide‐functional monomer units were introduced almost quantitatively. To optimize the reaction conditions, cationic polymerization of IBVE in the presence of amide compounds, as a model reaction, was also examined using various Lewis acids in dichloromethane. The combination of SnCl4 and ethyl acetate induced living cationic polymerization of IBVE at 0 °C when an amide compound, whose nitrogen is adjacent to a phenyl group, was used. The versatile performance of SnCl4 especially for achieving living cationic polymerization of various polar functional monomers was demonstrated in this study as well as in our previous studies. Thus, the specific properties of the SnCl4 initiating system are discussed by comparing with the EtxAlCl3?x systems from viewpoints of hard and soft acids and bases principle and computational chemistry. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6129–6141, 2008 相似文献
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Jeffrey N. McKnight Eric S. Tillman Louis R. Sarry 《Macromolecular rapid communications》2006,27(18):1578-1583
Summary: The cationic polymerization of poly(tert‐butyl vinyl ether) using N‐methyleneamine equivalents derived from a Lewis acid/1,3,5‐trimethylhexahydro‐1,3,5‐triazine (TMTA) co‐initiating system is reported. The resulting polymers possessed secondary amine functionality at the chain terminus, verified by derivatization with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl) and subsequent analysis with GPC‐UV (470 nm) and 1H NMR.
Use of N‐methyleneamine equivalents lacking aryl substituents to afford amine‐terminated poly(tert‐butyl vinyl ether). 相似文献
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Motomasa Yonezumi Reiko Takaku Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(6):2202-2211
Cationic polymerization of α‐methyl vinyl ethers was examined using an IBEA‐Et1.5AlCl1.5/SnCl4 initiating system in toluene in the presence of ethyl acetate at 0 ～ ?78 °C. 2‐Ethylhexyl 2‐propenyl ether (EHPE) had a higher reactivity, compared to corresponding vinyl ethers. But the resulting polymers had low molecular weights at 0 or ?50 °C. In contrast, the polymerization of EHPE at ?78 °C almost quantitatively proceeded, and the number‐average molecular weight (Mn) of the obtained polymers increased in direct proportion to the EHPE conversion with quite narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight ≤ 1.05). In monomer‐addition experiments, the Mn of the polymers shifted higher with low polydispersity as the polymerization proceeded, indicative of living polymerization. In the polymerization of methyl 2‐propenyl ether (MPE), the living‐like propagation also occurred under the reaction conditions similar to those for EHPE, but the elimination of the pendant methoxy groups was observed. The introduction of a more stable terminal group, quenched with sodium diethyl malonate, suppressed this decomposition, and the living polymerization proceeded. The glass transition temperature of the obtained poly(MPE) was 34 °C, which is much higher than that of the corresponding poly(vinyl ether). This poly(MPE) had solubility characteristics that differed from those of poly(vinyl ethers). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2202–2211, 2008 相似文献
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Arihiro Kanazawa Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2010,48(4):916-926
Cationic polymerization of isobutyl vinyl ether (IBVE) was examined using a variety of metal oxides in conjunction with IBVE–HCl adduct as a cationogen in toluene at 0 °C. Iron oxides (α‐Fe2O3, γ‐Fe2O3, and Fe3O4) induced living polymerization in the presence of an added base, ethyl acetate or 1,4‐dioxane, to give polymers with very narrow molecular weight distributions (MWDs). Conversely, with other metal oxides such as Ga2O3, In2O3, ZnO, Co3O4, and Bi2O3, polymers with bimodal MWDs, including long‐lived species along with uncontrolled higher molecular weight portions, were produced in the presence of an added base. A small amount of nBu4NCl or 2,6‐di‐tert‐butylpyridine (DTBP) suppressed the uncontrolled portion to induce controlled reactions with Ga2O3, In2O3, and ZnO. The roles of these reagents are discussed in terms of the nature of the active sites of the catalyst surface and the polymerization mechanisms. In addition, the reusability of the catalyst, the effect of stirring before and during polymerization, and the estimation of the number of active sites are also described. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 916–926, 2010 相似文献
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Jin Motoyanagi Taketo Ishikawa Masahiko Minoda 《Journal of polymer science. Part A, Polymer chemistry》2016,54(20):3318-3325
For the synthesis of brush‐shaped conjugated polymers consisting of a poly(phenylene butadiynylene) backbone and well‐defined poly(vinyl ether) (polyVE) side chains, we designed polyVE‐based macromonomers bearing a diethynyl benzene group at the terminus and applied them to the grafting through synthesis. The macromonomer (DE‐PIBVE) was synthesized by living cationic polymerization of isobutyl VE (IBVE) using a functionalized initiator (TMS‐DEVE‐TFA) having a TMS protected diethynyl benzene moiety, followed by deprotection of the TMS groups. As a result, we succeeded in the synthesis of the target brush‐shaped conjugated polymers [poly(DE‐PIBVE)] by oxidative coupling reaction of the diethynyl benzene groups. We found that the solution of poly(DE‐PIBVE) with a specific side chain length exhibited solvatochromism and thermochromism depending on the polarity of the media employed. This phenomenon was attributed to self‐assembly in polar media due to the intermolecular π–π interaction between neighboring conjugated polymer backbones, where the self‐assembly behavior would be closely related to the pendant polyVE structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3318–3325 相似文献
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Tomohide Yoshida Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2005,43(21):5138-5146
The living cationic polymerization of 4‐[2‐(vinyloxy)ethoxy]azobenzene (AzoVE) was achieved with various Lewis acids in the presence of an ester as an added base. When Et1.5AlCl1.5 was used as a catalyst, the living polymerization system was controllable by UV irradiation as a result of cis and trans isomerization of the azobenzene side groups. Furthermore, an initiating system consisting of SnCl4 and EtAlCl2 realized fast living polymerization of AzoVE. The polymerization rate of this system was 3 orders of magnitude faster than that obtained with Et1.5AlCl1.5. Poly(4‐[2‐(vinyloxy)ethoxy]azobenzene) was soluble in a diethyl ether/hexane mixture at 25 °C but became insoluble upon irradiation with UV light. This phase‐transition behavior was sensitive and reversible upon irradiation with UV or visible light and reflected the change in polarity occurring with cis and trans isomerization of the azobenzene side groups in the polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5138–5146, 2005 相似文献
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Motomasa Yonezumi Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(13):4495-4504
Cationic polymerization of 2,3‐dihydrofuran (DHF) and its derivatives was examined using base‐stabilized initiating systems with various Lewis acids. Living cationic polymerization of DHF was achieved using Et1.5AlCl1.5 in toluene in the presence of THF at 0 °C, whereas it has been reported that only less controlled reactions occurred at 0 °C. Monomer‐addition experiments of DHF and the block copolymerization with isobutyl vinyl ether demonstrated the livingness of the DHF polymerization: the number–average molecular weight of the polymers shifted higher with low polydispersity as the polymerization proceeded after the monomer addition. Furthermore, this base‐stabilized cationic polymerization system allowed living polymerization of ethyl 1‐propenyl ether and 4,5‐dihydro‐2‐methylfuran at ?30 and ?78 °C, respectively. In the polymerization of 2,3‐benzofuran, the long‐lived growing species were produced at ?78 °C. The obtained polymers have higher glass transition temperatures compared to poly(acyclic alkyl vinyl ether)s. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4495–4504, 2008 相似文献
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Hiroaki Shimomoto Dai Fukami Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2011,49(9):2051-2058
Partially fluorinated poly(vinyl ether)s with C4F9 and C6F12H groups in the side chain were synthesized via living cationic polymerization in the presence of an added base in a fluorine‐containing solvent, dichloropentafluoropropanes. For comparison, the polymerization of vinyl ether monomers with C2F5 and C6F13 groups and nonfluorinated monomers were also carried out. The characterization of the product polymers using size exclusion chromatography with a fluorinated solvent as an eluent indicated that all polymers had narrow molecular weight distributions (Mw/Mn ～ 1.1). Interestingly, the moderately fluorinated polymers with C4F9 exhibited upper critical solution temperature‐type phase separation in various organic solvents with wide‐ranging polarities, whereas highly fluorinated polymers with C6F13 are insoluble in nonfluorinated solvents. Polymers with C4F9 groups exhibited temperature dependent solubility transitions not only in common organic solvents (e.g., toluene, chloroform, tetrahydrofuran, and acetone) but also in perfluoro solvents [e.g., perfluoro(methylcyclohexane) and perfluorodecalin]. On the other hand, the solubility of polymers with C6F12H showed completely different from that of polymers with C6F13, despite their similar fluorine content. In addition, various types of fluorinated block copolymers were prepared in a living manner. The block copolymers with a thermosensitive fluorinated segment underwent temperature‐induced micellization and sol–gel transition in various organic solvents. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Hajime Kammiyada Makoto Ouchi Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):3082-3089
Herein, we clarified the ring-expansion cationic polymerization with a cyclic hemiacetal ester (HAE)-based initiator was versatile in terms of applicable vinyl ether monomers. Although there was a risk that higher reactive vinyl ethers may incur β-H elimination of the HAE-based cyclic dormant species to irreversibly give linear chains, the polymerizations were controlled to give corresponding cyclic polymers from various alkyl vinyl ethers of different reactivities. Functional vinyl ether monomers were also available, and for instance a vinyl ether monomer carrying an initiator moiety for metal-catalyzed living radical polymerization in the pendant allowed construction of ring-linear graft copolymers through the grafting-from approach. Furthermore, ring-based gel was prepared via the addition of divinyl ether at the end of the ring-expansion polymerization, where multi HAE bonds cyclic polymers or fused rings were crosslinked with each other. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3082–3089 相似文献
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