Hyperbranched Polymers via RAFT Copolymerization of an Acryloyl Trithiocarbonate

2007 ◽  
Vol 60 (6) ◽  
pp. 396 ◽  
Author(s):  
Andrew P. Vogt ◽  
Sudershan R. Gondi ◽  
Brent S. Sumerlin
Keyword(s):  
Click Chemistry ◽  
Lower Critical Solution Temperature ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Chain Transfer Agent ◽  
Solution Temperature ◽  
Dipolar Cycloaddition ◽  
Critical Solution Temperature ◽  
Reversible Addition ◽  
End Groups

Hyperbranched copolymers of N-isopropylacrylamide (NIPAM) and styrene were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of a novel acryloyl trithiocarbonate, namely 1-[3-(2-methyl-2-dodecylsulfanylthiocarbonylsulfanylpropionyloxy)propyl]-1H-[1,2,3]triazol-4-ylmethyl acrylate. By employing an example of ‘click chemistry’, we were able to prepare the vinyl RAFT chain transfer agent (CTA) by copper-catalyzed 1,3-dipolar cycloaddition of an azido-functionalized trithiocarbonate and propargyl acrylate. The resulting CTA facilitated the preparation of highly branched poly(N-isopropylacrylamide) (PNIPAM) and polystyrene. Interestingly, the branched PNIPAM demonstrated a reduced lower critical solution temperature (LCST) of 25°C as opposed to the conventional value of 32°C expected for linear PNIPAM, an effect attributed to increased contribution of hydrophobic dodecyl trithiocarbonate end groups.

scholarly journals Thermoresponsive and Redox Behaviors of Poly(N-isopropylacrylamide)-Based Block Copolymers Having TEMPO Groups as Their Side Chains

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Toru Uemukai ◽  
Tomoya Hioki ◽  
Manabu Ishifune
Keyword(s):  
Block Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Solution Temperature ◽  
Thermoresponsive Polymer ◽  
Critical Solution Temperature ◽  
Redox Active ◽  
Reversible Addition ◽  
Polymerization Conditions ◽  
Active Block

Thermoresponsive and redox-active block copolymers having 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) moieties have been synthesized by using the reversible addition-fragmentation chain transfer (RAFT) polymerization technique.N-Isopropylacrylamide (NIPAAm) and 2,2,6,6-tetramethylpiperidyl methacrylate (TEMPMA) monomers were copolymerized stepwise under RAFT polymerization conditions to afford the thermoresponsive block copolymers, PNIPAAm-block-PTEMPMA and PNIPAAm-block-PTEMPMA-block-PNIPAAm. Oxidation of tetramethylpiperidine groups in the copolymers successfully afforded the corresponding TEMPO-containing block copolymers. The resulting triblock copolymer was found to be thermoresponsive showing lower critical solution temperature (LCST) at 34∘C in its aqueous solution. Redox behavior of the resulting copolymer was observed by cyclic voltammetry. The potential of anodic current peak changed below and above the LCST of the block copolymer. These results indicate that the phase transition of thermoresponsive polymer influences the redox potential of TEMPO moieties.

scholarly journals Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

2012 ◽  
Vol 8 ◽  
pp. 1929-1935 ◽  
Author(s):  
Gero Maatz ◽  
Arkadius Maciollek ◽  
Helmut Ritter
Keyword(s):  
Acid Chloride ◽  
Lower Critical Solution Temperature ◽  
Azo Dye ◽  
Chain Transfer ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
End Groups ◽  
Hyperbranched Polyglycerol ◽  
A Chain ◽  
End Group

A thermo-, pH- and cyclodextrin- (CD) responsive poly(N-isopropylacrylamide) (PNIPAM), with a N,N-dimethylaminoazobenzene end group was synthesized. Using 3-mercaptopropionic acid as a chain transfer agent, PNIPAM with a well-defined COOH end group was obtained. The acid end group was transferred to the corresponding acid chloride and then functionalized with N,N-dimethyl[4-(4’-aminophenylazo)phenyl]amine. This dye-end-group-labeled polymer showed acidochromic effects, depending on the pH and the presence of randomly methylated β-cyclodextrin (RAMEB-CD). Also higher cloud-point values for the lower critical solution temperature (LCST) in the presence of RAMEB-CD were observed. Additionally, this azo-dye-end-group-labeled polymer was complexed with hyperbranched polyglycerol (HPG) decorated with β-CD to generate hedgehog-like superstructures.

RAFT Polymerization of 2,2,3,3-Tetrafluoropropyl Methacrylate in the Presence of Lewis Acids

2021 ◽  
Vol 899 ◽  
pp. 525-531
Author(s):  
Oleg A. Lebedev ◽  
Alexandra O. Grigoreva ◽  
Sergey D. Zaitsev
Keyword(s):  
Polymer Chain ◽  
Lewis Acids ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Point Of View ◽  
Chain Transfer Agent ◽  
Reversible Addition

The influence of various tacticity regulators on the reversible addition-fragmentation (RAFT) polymerization of 2,2,3,3-tetrafluoropropyl methacrylate in the presence of 2-cyano-2-propyldodecyltritiocarbonate as an chain transfer agent was investigated. Among Lewis acids considered, the polymerization of TFPMA in dioxane with ZnBr2 turned out to be the most effective from the point of view of tacticity; the polymer with the highest isotacticity is formed. The addition of hexafluoroisopropanol leads to an increase in the heterotacticity and a decrease in the isotacticity of the polymer chain.

Synthesis and Investigation of pH-Switchable RAFT Agent in Polymerization of Styrene

2021 ◽  
Vol 899 ◽  
pp. 638-643
Author(s):  
Artem Vlasov ◽  
Alexandra O. Grigoreva ◽  
Sergey D. Zaitsev
Keyword(s):  
Mass Distribution ◽  
Molar Mass ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Chain Transfer Agent ◽  
Molar Mass Distribution ◽  
Reversible Addition ◽  
Raft Agent ◽  
Kinetic Features

pH-switchable chain transfer agent 1-cyano-1-methylethyl (phenyl)(pyridin-4-yl)-carbamodithioate (CMPC) was synthesized and reversible addition-fragmentation chain-transfer (RAFT) polymerization of styrene in presence of CMPC was studied. It was shown that presence of CMPC affects molar mass distribution and kinetic features and realizes supposed mechanism of RAFT polymerization. Different effect of CMPC on polymerization of styrene in presence of protic acids was studied.

Degradable Hydrogels for Tissue Engineering - Part II: Responses of Fibroblasts and Macrophages to Linear PHEMA

2010 ◽  
Vol 8 ◽  
pp. 91-104 ◽  
Author(s):  
Imelda Keen ◽  
Traian V. Chirila ◽  
Zeke Barnard ◽  
Z. Zainuddin ◽  
Andrew K. Whittaker
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Macrophage Cell Line ◽  
Macrophage Cell ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Murine Fibroblasts ◽  
End Groups ◽  
Linear Poly ◽  
A Chain

A series of linear poly(2-hydroxyethyl methacrylate) (PHEMA) with defined molecular weights (MW) and narrow molecular distributions were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using cumyl dithiobenzoate (CDB) as a chain transfer agent. Murine fibroblasts (3T3) were exposed to eluates from various PHEMA samples, washed or unwashed, and with or without dithioester end groups. After 72 hrs in cell culture, no cytotoxic response was elicited by the polymer samples devoid of dithioester end groups, and which also underwent a thorough washing regime. Specimens throughout the entire MW range were internalized by a macrophage (cell line Raw 264), suggesting that such polymers can be used as models for studying the biodegradation of PHEMA.

Trehalose-functionalized block copolymers form serum-stable micelles

2014 ◽  
Vol 5 (17) ◽  
pp. 5160-5167 ◽  
Author(s):  
Swapnil R. Tale ◽  
Ligeng Yin ◽  
Theresa M. Reineke
Keyword(s):  
Block Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Chain Transfer Agent ◽  
Macromolecular Chain ◽  
Reversible Addition ◽  
Poly Ethylene

Well-defined amphiphilic diblock terpolymers of poly(ethylene-alt-propylene)–poly[(N,N′-dimethylacrylamide)-grad-poly(6-deoxy-6-methacrylamido trehalose)] (denoted as PEP–poly(DMA-grad-MAT) or PT) have been synthesized using a PEP macromolecular chain transfer agent by reversible addition–fragmentation chain transfer (RAFT) polymerization.

Access to cyclic polystyrenes via a combination of reversible addition fragmentation chain transfer (RAFT) polymerization and click chemistry

Polymer ◽  
2008 ◽  
Vol 49 (9) ◽  
pp. 2274-2281 ◽  
Author(s):  
Anja S. Goldmann ◽  
Damien Quémener ◽  
Pierre-Eric Millard ◽  
Thomas P. Davis ◽  
Martina H. Stenzel ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Reversible Addition
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