Sadahito Aoshima

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTA Renaissance in Living Cationic PolymerizationSadahito Aoshima* and Shokyoku KanaokaView Author Information Department of Macromolecular Science, Graduate School of Science, Osaka University* To whom correspondence should be addressed. E-mail: [email protected]. Phone: +81-6-6850-5448. Fax: +81-6-6850-5448.Cite this: Chem. Rev. 2009, 109, 11, 5245–5287Publication Date (Web):October 5, 2009Publication History Received22 June 2009Published online5 Octobe

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiving cationic polymerization of vinyl monomers by organoaluminum halides. 3. Living polymerization of isobutyl vinyl ether by ethyldichloroaluminum in the presence of ester additivesSadahito Aoshima and Toshinobu HigashimuraCite this: Macromolecules 1989, 22, 3, 1009–1013Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://pubs.acs.org/doi/10.1021/ma00193a001https://doi.org/10.1021/

Abstract Living cationic polymerization of alkoxyethyl vinyl ether [CH 2 CHOCH 2 CH 2 OR; R: CH 3 (MOVE), C 2 H 5 (EOVE)] and related vinyl ethers with oxyethylene units in the pendant was achieved by 1‐(isobutoxy)ethyl acetate ( 1 )/Et 1.5 AlCl 1.5 initiating system in the presence of an added base (ethyl acetate or THF) in toluene at 0°C. The polymers had a very narrow molecular weight distribution (M̄ w /M̄ n = 1.1–1.2) and the M̄ n proportionally increased with the progress of the polymeriz

Abstract Stimuli‐responsive ABC triblock copolymers with three segments with different phase‐separation temperatures were synthesized via sequential living cationic copolymerization. The triblock copolymers exhibited sensitive thermally induced physical gelation (open association) through the formation of micelles. For example, an aqueous solution of EOVE 200 ‐ b ‐MOVE 200 ‐ b ‐EOEOVE 200 [where EOVE is 2‐ethoxyethyl vinyl ether, MOVE is 2‐methoxethyl vinyl ether and EOEOVE is 2‐(2‐ethoxy)ethoxy

Diblock copolymers of vinyl ethers with oxyethylene pendants were synthesized by living cationic polymerization in the presence of an added base. The characteristic physical gelation behavior was examined by varying the temperature of aqueous polymer solutions. When the solution was allowed to warm, physical gelation occurred quite sensitively in a limited temperature region, maintaining transparency.

Abstract Our recent extensive research on Lewis acid catalysts with a weak base for the cationic polymerization of vinyl ethers led to unprecedented living reaction systems: fast living polymerization within 1–3 s; a wide choice of metal halides containing Al, Sn, Fe, Ti, Zr, Hf, Zn, Ga, In, Si, Ge, and Bi; and heterogeneously catalyzed living polymerization with Fe 2 O 3 . The use of added bases for the stabilization of the propagating carbocation and the appropriate selection of Lewis acid cat

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiving cationic polymerization of vinyl ethers with a functional group. 1. Polymerization of 2-acetoxyethyl vinyl ether and synthesis of polyalcohols with a narrow molecular weight distributionSadahito Aoshima, Takayuki Nakamura, Norimasa Uesugi, Mitsuo Sawamoto, and Toshinobu HigashimuraCite this: Macromolecules 1985, 18, 11, 2097–2101Publication Date (Print):November 1, 1985Publication History Published online1 May 2002Published inissue 1 November 19

A metal-free initiating system for the living cationic polymerization of alkyl vinyl ethers (VEs) and styrene derivatives was developed using diaryliodonium salts as an organic Lewis acid catalyst. Unlike many past examples of their use as a photoinitiator, diaryliodonium salts were demonstrated to function as a Lewis acid catalyst for cationic polymerization. The cationic polymerization of isobutyl VE smoothly proceeded using a diaryliodonium salt in conjunction with a cationogen that generates

Abstract Vinyl ether polymers with imidazolium or pyridinium salt pendants underwent sensitive lower critical solution temperature (LCST)‐type phase separation in organic media. Well‐defined poly(salts) were quantitatively prepared by reaction with corresponding imidazoles or pyridines and poly(2‐chloroethyl vinyl ether), which was synthesized by living cationic polymerization. For example, a solution of the homopolymer with butyl imidazolium salts exhibited a sharp and reversible transition in

A conventional catalyst, SnCl4, for cationic polymerization, combined with EtAlCl2 and an ester as an added base, has been used to realize the fast living cationic polymerization of not only alkyl vinyl ethers but also those containing hetero atoms in the pendant. Two important features of this system are the clearly defined roles of two Lewis acids: EtAlCl2 generates initiating species quantitatively from 1-(isobutoxy)ethyl acetate [CH3CH(OiBu)OCOCH3], and SnCl4 accelerates the polymerization,

Abstract The living cationic polymerization of several functional monomers in the presence of an added base is investigated as a possible preparation of a new series of water‐soluble or stimuli‐responsive copolymers. Under appropriate conditions, the polymerization allows the selective preparation of polymers with various shapes and different sequence distributions of monomer units, including stimuli‐responsive block copolymers, gradient copolymers, poly(vinyl alcohol) graft copolymers, and star

Abstract Stimuli‐responsive gradient copolymers, composed of various monomers, were synthesized by living cationic polymerization in the presence of base. The monomers included thermosensitive 2‐ethoxyethyl vinyl ether (EOVE) and 2‐methoxyethyl vinyl ether (MOVE), hydrophobic isobutyl vinyl ether (IBVE) and 2‐phenoxyethyl vinyl ether (PhOVE), crystalline octadecyl vinyl ether (ODVE), and hydrophilic 2‐hydroxyethyl vinyl ether (HOVE). The synthesis of gradient copolymers was conducted using a sem