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Transfer agent

About: Transfer agent is a(n) research topic. Over the lifetime, 894 publication(s) have been published within this topic receiving 9799 citation(s).
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Journal ArticleDOI
01 Nov 1995-Macromolecules
Abstract: Control of the radical polymerization of styrene and acrylates has been achieved by using alkyl iodides in a degenerative transfer process. Various transfer agents of the type R-I were explored. Of those examined, 1-phenylethyl iodide, iodoacetonitrile, and iodoform were found to be effective in controlling molecular weights and for providing polymers with relatively low polydispersities, M w /M n ≤ 1.5. Relatively good control has been also achieved with perfluoroalkyl iodides, whereas most alkyl and aryl iodides have been ineffective transfer agents. Also explored were the effects of initiator structure and reaction temperature on the polymerization systems.

217 citations

Journal ArticleDOI
07 Jun 2003-Langmuir
Abstract: Reversible addition−fragmentation chain transfer (RAFT) is a versatile, controlled free radical polymerization technique that operates via a degenerative transfer mechanism in which a thiocarbonylthio compound acts as a chain transfer agent. The subsequent reduction of the dithioester end groups to thiols allows the preparation of (co)polymer-modified gold surfaces. Herein we report the immobilization of poly(sodium 4-styrenesulfonate), poly((ar-vinylbenzyl) trimethylammonium chloride), poly(N,N-dimethylacrylamide), and poly(3-[2-(N-methylacrylamido)-ethyldimethyl ammonio]propane sulfonate-b-N,N-dimethylacrylamide) onto gold films. The presence of the immobilized (co)polymers was confirmed by atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and surface contact angle measurements. The gold film modified with the block copolymer demonstrated stimuli-responsive behavior as evidenced by its water contact angle being similar to that of poly(N,N-dimethylacrylamide) ...

191 citations

Journal ArticleDOI
20 Nov 2003-Macromolecules
Abstract: Controlled/living radical polymerization of vinyl acetate was achieved by a degenerative transfer process using alkyl iodides as transfer agents. Poly(vinyl acetate) with predetermined molecular weight and relatively low polydispersity was successfully synthesized. Methyl 2-iodopropionate and ethyl iodoacetate were employed as transfer agents, whereas 2,2‘-azobis(isobutyronitrile) and α-cumyl peroxyneodecanoate were used as initiators. Methyl 2-iodopropionate and ethyl iodoacetate are both efficient transfer agents, yielding polymers with good agreement between theoretical and observed molecular weights up to Mn = 20 000 and low polydispersities (Mw/Mn < 1.5). In contrast, ethyl iodide was inefficient as a transfer agent, although it retarded polymerization. The influence of temperature and the concentrations of transfer agent and initiator were studied. The structure of poly(vinyl acetate) end groups was investigated using 1H NMR. The iodo-terminated chain ends were unstable and decomposed to aldehyde mo...

180 citations

Journal ArticleDOI
12 Apr 2016-ACS Macro Letters
Abstract: We report the use of visible light to mediate a RAFT dispersion polymerization in the absence of external catalyst or initiator to yield nanoparticles of different morphologies according to a polymerization-induced self-assembly (PISA) mechanism. A POEGMA macro-chain transfer agent (macro-CTA) derived from a 4-cyano-4-((dodecylsulfanylthiocarbonyl)sulfanyl)pentanoic acid (CDTPA) RAFT agent can be activated under blue (460 nm, 0.7 mW/cm2) or green (530 nm, 0.7 mW/cm2) light and act simultaneously as a radical initiator, chain transfer agent, and particle stabilizer under ethanolic dispersion conditions. In particular, the formation of worm-like micelles was readily monitored by the increase of reaction viscosity during the polymerization; this method was shown to be particularly robust to different reaction parameters such as macro-CTAs of varying molecular weight. Interestingly, at high monomer conversion, different morphologies were formed depending on the wavelength of light employed, which may be due t...

157 citations

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Topic's top 5 most impactful authors

Nakayama Yasuhide

8 papers, 17 citations

Alain Guyot

5 papers, 76 citations

Howard Alper

5 papers, 102 citations

Yves Gnanou

4 papers, 20 citations

Marc A. Hillmyer

4 papers, 199 citations