Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization of Vinyl Monomers Initiated by Poly(methyl methacrylate) Peroxide

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhengbiao Zhang ◽  
Xiulin Zhu ◽  
Jian Zhu ◽  
Zhenping Cheng

AbstractPoly(methyl methacrylate) peroxide (PMMAP) was synthesized and used as the initiator in the reversible addition-fragmentation chain transfer (RAFT) polymerization. Methyl methacrylate (MMA) as the monomer and 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the chain transfer agent was used in the polymerization system. The polymerization was successfully initiated by PMMAP while maintaining features of “living”/controlled radical polymerization such as the number-average molecular weights (Mn) increasing linearly with the monomer conversions and low polydispersity index (PDI) values. The results of 1H NMR and IR spectra confirmed that a small quantity of polymer chains were derived from the PMMAP moieties. The PMMAP can also initiate the RAFT polymerization of styrene (St) and methyl acrylate (MA), and the polymerization proceeded in a “living”/controlled fashion.

2011 ◽  
Vol 64 (12) ◽  
pp. 1602 ◽  
Author(s):  
Yingkai Liu ◽  
Mei Li ◽  
Dengxu Wang ◽  
Jinshui Yao ◽  
Jianxing Shen ◽  
...  

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.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhou Nianchen ◽  
Zhu Jian ◽  
Zhang Zhengbiao ◽  
Zhu Xiulin

AbstractA novel dithioester, bearing anthracene as Z group, benzyl anthracene-10-carbodithioate (BAC) was successfully synthesized and used as the RAFT agent for the RAFT polymerizations of styrene (St). The results indicated that the polymerization presented the characteristics of “living”/controlled radical polymerization. 1H NMR characterization of obtained polystyrene confirmed that most of the polymer chains were end-capped by the anthracene moiety. The successful chain extension experiment further demonstrated the “living” character of the polymer. The fluorescence investigation of the polymers contained an anthrancene moiety of BAC in the chain end expressed enhanced fluorescence property than that of BAC in CHCl3 solution.


2010 ◽  
Vol 88 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Chih-Feng Huang ◽  
Jeong Ae Yoon ◽  
Krzysztof Matyjaszewski

Amphiphilic block copolymers poly(N-vinylcarbazole)-b-poly(N-vinylpyrrolidone) (PNVK-b-PNVP) were prepared by xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Both the PNVK and PNVP macroinitiators and the resulting block copolymers had molecular weights close to theoretical values, predicted for efficient initiation, in the range of Mn = 30 000 to 90 000. The block copolymers dissolved in several organic solvents but, depending on their composition, in methanol formed either micelles or large aggregates, as confirmed by dynamic light scattering. The presence of globular aggregates was confirmed by tapping mode atomic force microscopy.


2011 ◽  
Vol 89 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Binxin Li ◽  
Daniel Majonis ◽  
Peng Liu ◽  
Mitchell A. Winnik

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.


e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaoming Wan ◽  
Zhengbiao Zhang ◽  
Xiulin Zhu ◽  
Jian Zhu ◽  
Zhenping Cheng

AbstractThree azobenzene-based dithiocarbamates, 2-(phenylazo-phenoxycarbonyl) prop-2-yl 9H-carbazole-9-carbodithioate (APCDT), 2-(4-nitro-phenylazophenoxy- carbonyl)prop-2-yl 9H-carbazole-9-carbodithioate (ANPCDT), 2-(4-cyanophenylazo- phenoxy-carbonyl)pro-2-yl 9H-carbazole-9-carbodithioate (ACPCDT), were synthesized and used as RAFT agents in the polymerizations of styrene (St) and methyl methacrylate (MMA). The results showed that APCDT, ACPCDT and ANPCDT were effective RAFT agents for the polymerization of St. In the case of MMA, the polymerization showed hybrid behavior. The different substitutes on azobenzene moiety in dithiocarbamates did not show obvious influence on the controllability of the polymerizations. The UV and fluorescence spectra of RAFT agents and obtained azobenzene-terminated polymers were investigated


2004 ◽  
Vol 58 (11) ◽  
pp. 514-520
Author(s):  
Milena Avramovic ◽  
Lynne Katsikas ◽  
Branko Dunjic ◽  
Ivanka Popovic

The fundamentals of controlled radical polymerization are presented in this review. The paper focuses on reversible addition fragmentation chain transfer (RAFT) polymerization. The mechanism and specifics of this type of polymerization are discussed, as are the possibilities of synthesizing complex macro-molecular structures. The synthesis and properties of RAFT agents, of the general structure Z-C(=S)-S-R, are presented.


2020 ◽  
Vol 9 (12) ◽  
pp. 1853-1857
Author(s):  
Yu-Cheng Wang ◽  
Rina Maeda ◽  
Gergely Kali ◽  
Hideaki Yokoyama ◽  
Gerhard Wenz ◽  
...  

2019 ◽  
Vol 72 (7) ◽  
pp. 479 ◽  
Author(s):  
Amin Reyhani ◽  
Thomas G. McKenzie ◽  
Qiang Fu ◽  
Greg G. Qiao

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.


e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhengji Song ◽  
Carole Pelletier ◽  
Yinghua Qi ◽  
Jasim Ahmed ◽  
Sunil K. Varshney ◽  
...  

AbstractABA and/or ABC type triblock copolymers were synthesized by living anionic and controlled radical polymerization in which poly(methyl methacrylate) was used as central block. The structural composition of these block copolymers were determined by 1H NMR. The block length/molecular weight and microstructure of these polymers were measured by SEC. The microstructure of resultant central alkyl methacrylate block can be tailored from highly syndiotactic to highly isotactic structure by varying the solvent and/or initiator. The thermal and rheological properties of center poly(methyl methacrylate) block and poly(styreneb- methyl methacrylate-b- styrene) tri block copolymers were studied in detail.


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