Synthesis and characterization of a naphthalimide–dye end-labeled copolymer by reversible addition–fragmentation chain transfer (RAFT) polymerization

2011 ◽  
Vol 89 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Binxin Li ◽  
Daniel Majonis ◽  
Peng Liu ◽  
Mitchell A. Winnik
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymer Composition ◽  
Cooh Group ◽  
Agent Based ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Use ◽  
Naphthalimide Dye

We describe the synthesis of an end-functionalized copolymer of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-hydroxysuccinimide methacrylate (NMS) by reversible addition–fragmentation chain transfer (RAFT) polymerization. To control the polymer composition, the faster reacting monomer (NMS) was added slowly to the reaction mixture beginning 30 min after initating the polymerization (ca. 16% HPMA conversion). One RAFT agent, based on azocyanopentanoic acid, introduced a –COOH group to the chain at one end. Use of a different RAFT agent containing a 4-amino-1,8-naphthalimide dye introduced a UV–vis absorbing and fluorescent group at this chain end. The polymers obtained had molecular weights of 30 000 and 20 000, respectively, and contained about 30 mol% NMS active ester groups.

Reversible addition fragmentation chain transfer (RAFT) polymerization of styrene in fluid CO2

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Toshihiko Arita ◽  
Sabine Beuermann ◽  
Michael Buback ◽  
Philipp Vana
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Significant Difference ◽  
Raft Agent ◽  
Successful Control ◽  
A Minor ◽  
Peak Widths

Abstract Reversible addition fragmentation chain transfer (RAFT) polymerizations of styrene in fluid CO2 have been carried out at 80°C and 300 bar using cumyl dithiobenzoate as the controlling agent in the concentration range of 3.5·10-3 to 2.1·10-2 mol/L. This is the first report on RAFT polymerization in fluid CO2. The polymerization rates were retarded depending on the employed RAFT agent concentration with no significant difference between the RAFT polymerization performed in fluid CO2 and in toluene. Full chain length distributions were analyzed with respect to peak molecular weights, indicating the successful control of radical polymerization in fluid CO2. A characterization of the peak widths may suggest a minor influence of fluid CO2 on the addition reaction of macroradicals on the dithiobenzoate group.

scholarly journals Redox-Initiated Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization

2019 ◽  
Vol 72 (7) ◽  
pp. 479 ◽  
Author(s):  
Amin Reyhani ◽  
Thomas G. McKenzie ◽  
Qiang Fu ◽  
Greg G. Qiao
Keyword(s):  
Redox Reactions ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Molecular Structures ◽  
Biologically Relevant ◽  
Molecular Weights ◽  
Polymeric Biomaterials ◽  
Reversible Addition ◽  
Wide Range ◽  
Metal Catalyzed

Reversible addition–fragmentation chain transfer (RAFT) polymerization initiated by a radical-forming redox reaction between a reducing and an oxidizing agent (i.e. ‘redox RAFT’) represents a simple, versatile, and highly useful platform for controlled polymer synthesis. Herein, the potency of a wide range of redox initiation systems including enzyme-mediated redox reactions, the Fenton reaction, peroxide-based reactions, and metal-catalyzed redox reactions, and their application in initiating RAFT polymerization, are reviewed. These redox-RAFT polymerization methods have been widely studied for synthesizing a broad range of homo- and co-polymers with tailored molecular weights, compositions, and (macro)molecular structures. It has been demonstrated that redox-RAFT polymerization holds particular promise due to its excellent performance under mild conditions, typically operating at room temperature. Redox-RAFT polymerization is therefore an important and core part of the RAFT methodology handbook and may be of particular importance going forward for the fabrication of polymeric biomaterials under biologically relevant conditions or in biological systems, in which naturally occurring redox reactions are prevalent.

scholarly journals Synthesis and characterization of triphenylamine and Bbis(indolyl)methane center-functionalized polymer via reversible addition-fragmentation chain transfer polymerization

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Jie Xu ◽  
Wei Shang ◽  
Jian Zhu ◽  
Zhenping Cheng ◽  
Nianchen Zhou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Chloroform Solution ◽  
Monomer Conversion ◽  
Benzyl Ester ◽  
Chain Extension ◽  
Reversible Addition ◽  
Raft Agent ◽  
Cyclic Voltammetry Method

AbstractA novel bis-functional reversible addition-fragmentation chain transfer (RAFT) agent bearing triphenylamine (TPA) and bis(indolyl)methane (BIM) groups, {4-[bis(1-carbodithioic acid benzyl ester-indol-3-yl)methyl]phenyl}diphenylamine (BCIMPDPA), was synthesized and successfully used as the RAFT agent to mediate the polymerization of styrene (St). The polymerization results showed that reversible addition-fragmentation chain transfer (RAFT) polymerization of St could be well controlled. The kinetic plot showed it was of first order and the numberaverage molecular weight (Mn(GPC)) of the polymer measured by GPC increased linearly with monomer conversion, simultaneously, the molecular weight distribution of the polymer was also relatively narrow. In addition, the existence of the TPA and BIM groups in the middle of polymer chain was confirmed by chain extension reaction and 1H NMR spectrum. The optical properties of the functionalized polystyrene (PS) in chloroform solution were also investigated. Furthermore, the redox process of the RAFT agent and the functionalized PS were studied by cyclic voltammetry method.

RAFT Polymerization of Monomers with Highly Disparate Reactivities: Use of a Single RAFT Agent and the Synthesis of Poly(styrene-block-vinyl acetate)

2013 ◽  
Vol 66 (12) ◽  
pp. 1564 ◽  
Author(s):  
Lily A. Dayter ◽  
Kate A. Murphy ◽  
Devon A. Shipp
Keyword(s):  
Block Copolymers ◽  
Vinyl Acetate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Good Control ◽  
Scanning Calorimetry ◽  
Styrene Polymerization ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Group

A single reversible addition–fragmentation chain transfer (RAFT) agent, malonate N,N-diphenyldithiocarbamate (MDP-DTC) is shown to successfully mediate the polymerization of several monomers with greatly differing reactivities in radical/RAFT polymerizations, including both vinyl acetate and styrene. The chain transfer constants (Ctr) for MDP-DTC for both these monomers were evaluated; these were found to be ~2.7 in styrene and ~26 in vinyl acetate, indicating moderate control over styrene polymerization and good control of vinyl acetate polymerization. In particular, the MDP-DTC RAFT agent allowed for the synthesis of block copolymers of these two monomers without the need for protonation/deprotonation switching, as has been previously developed with N-(4-pyridinyl)-N-methyldithiocarbamate RAFT agents, or other end-group transformations. The thermal properties of the block copolymers were studied using differential scanning calorimetry, and those with sufficiently high molecular weight and styrene composition appear to undergo phase separation. Thus, MDP-DTC may be useful for the production of other block copolymers consisting of monomers with highly dissimilar reactivities.

scholarly journals Synthesis of Poly(3-vinylpyridine)-Block-Polystyrene Diblock Copolymers via Surfactant-Free RAFT Emulsion Polymerization

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3145 ◽  
Author(s):  
Katharina Nieswandt ◽  
Prokopios Georgopanos ◽  
Clarissa Abetz ◽  
Volkan Filiz ◽  
Volker Abetz
Keyword(s):  
Emulsion Polymerization ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Free Water ◽  
Monomer Conversion ◽  
Molecular Weights ◽  
Reversible Addition

In this work, we present a novel synthetic route to diblock copolymers based on styrene and 3-vinylpyridine monomers. Surfactant-free water-based reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization of styrene in the presence of the macroRAFT agent poly(3-vinylpyridine) (P3VP) is used to synthesize diblock copolymers with molecular weights of around 60 kDa. The proposed mechanism for the poly(3-vinylpyridine)-block-poly(styrene) (P3VP-b-PS) synthesis is the polymerization-induced self-assembly (PISA) which involves the in situ formation of well-defined micellar nanoscale objects consisting of a PS core and a stabilizing P3VP macroRAFT agent corona. The presented approach shows a well-controlled RAFT polymerization, allowing for the synthesis of diblock copolymers with high monomer conversion. The obtained diblock copolymers display microphase-separated structures according to their composition.

PolyPEGylation of Protein using Semitelechelic and Mid-functional Poly(PEGMA)s synthesized by RAFT polymerization

2011 ◽  
Vol 64 (12) ◽  
pp. 1602 ◽  
Author(s):  
Yingkai Liu ◽  
Mei Li ◽  
Dengxu Wang ◽  
Jinshui Yao ◽  
Jianxing Shen ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymer Chains ◽  
High Yield ◽  
Protein Surface ◽  
Molecular Weights ◽  
Pharmaceutical Protein ◽  
Reversible Addition ◽  
Poly Ethylene

A series of well defined semitelechelic and mid-functionalized poly(poly(ethylene glycol) methyl ether methacrylate)s (poly(PEGMA)s) were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization using thiazolidine-2-thione-functionalized chain transfer agents (CTAs). The thiazolidine-2-thione group was located either at the end or in the middle of polymer chains depending on the different structural CTAs. All polymers were fully analyzed by 1H NMR spectroscopy and GPC, confirming their well-defined structures, such as predesigned molecular weights, narrow polydispersity indices, and high yield chain-end or chain-middle functionalization. The thiazolidine-2-thione functionality located at the end of or at the middle of the polymer chains can react with amine residues on protein surfaces, forming protein-polymer conjugates via amide linkages. The bioactivity of protein conjugates were subsequently tested using micrococcus lysodeikticus cell as substitute. The protein conjugations from the mid-functionalized polymer remained much more protein bioactivity comparing to their semitelechelic counterpart with similar molecular weights, indicating the steric hindrance of the mid-functionalized poly(PEGMA)s lead to the better selective conjugation to protein. The number of polymer chains on the protein surface was additionally evaluated by TNBS analysis, exhibiting that there are less mid-functionalized poly(PEGMA)s linked on the protein surface than the semitelechelic polymers, also supporting the hypothesis that the steric hindrance from branch-structural polymers results in the better reaction selectivity. This synthetic methodology is suitable for universal proteins, seeking a balance between the protein bioactivity and the protein protection by the covalent linkage with polymer, and exhibits promising potential for pharmaceutical protein conjugation.

Synthetic Polyampholytes Based Cryoprotective Agents by Reversible Addition Fragmentation Chain Transfer Polymerisation

2013 ◽  
Vol 1499 ◽  
Author(s):  
Robin Rajan ◽  
Kazuaki Matsumura
Keyword(s):  
Chain Transfer ◽  
High Efficiency ◽  
Raft Polymerization ◽  
Freezing And Thawing ◽  
Cryoprotective Agents ◽  
Reversible Addition ◽  
Raft Agent ◽  
High Cytotoxicity ◽  
Methylpropionic Acid ◽  
Polymerization Method

ABSTRACTDimethyl sulfoxide (DMSO) and several naturally occurring polyols or their derivatives (like glycerol) have been used as cryoprotective agents (CPAs) for many years. However DMSO shows high cytotoxicity and affects differentiation of cells, so it needs to be removed immediately after thawing, whereas polyols are comparatively weaker cryoprotective agents. Furthermore, some types of cells are extremely sensitive to damage during freezing and thawing, so cannot be cryopreserved properly using current CPAs. So there is a great need to develop newer cryoprotective agents with lower cytotoxicity and high efficiency for many biological and medical purposes.Recently we showed that carboxylated poly-L-lysine, which is classified as a polyampholyte, has a cryoprotective effect on cells in solution without any other cryoprotectant. Polyampholytes are charged polymers with both positively and negatively charged groups.Therefore, in this research, we are developing a completely synthetic polyampholytes by radical polymerization and will try to elucidate the key parameters of cryoprotective properties. Here we chose reversible addition fragmentation chain transfer (RAFT) polymerization as the mode of polymerization as it is a kind of living polymerization method and can give control over the molecular weight and composition of the copolymer. We evaluated the livingness of the 1:1 copolymer with methacrylic acid (MAA) and 2-Dimethylamino ethyl methacrylate (DMAEMA) with 2-(Dodecylthiocarbonothioylthio)-2-methylpropionic acid as the RAFT agent and the polymer solution showed good cell viability of L929 cells after cryopreservation at 15% copolymer concentration.

Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization in Miniemulsion Based on In Situ Surfactant Generation

2011 ◽  
Vol 64 (8) ◽  
pp. 1033 ◽  
Author(s):  
S. R. Simon Ting ◽  
Eun Hee Min ◽  
Per B. Zetterlund
Keyword(s):  
Potassium Hydroxide ◽  
Colloidal Stability ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Miniemulsion Polymerization ◽  
High Energy ◽  
Reversible Addition ◽  
Raft Agent ◽  
Surface Active

Reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The best results were obtained using the RAFT agent 3-benzylsulfanyl thiocarbonyl sufanylpropionic acid (BSPAC), most likely as a result of the presence of a carboxylic acid functionality in the RAFT agent that renders it surface active and thus imparts increased colloidal stability. Stable final miniemulsions were obtained with no coagulum with particle diameters less than 200 nm. The results demonstrate that the RAFT miniemulsion polymerization of styrene employing the low energy in situ surfactant method is challenging, but that a system that proceeds predominantly by a miniemulsion mechanism can be achieved under carefully selected conditions.

Sign in / Sign up

Export Citation Format

Share Document