Diverse approaches to star polymers via cationic and radical RAFT cross-linking reactions using mechanistic transformation

2017 ◽  
Vol 8 (38) ◽  
pp. 5972-5981 ◽  
Author(s):  
Mineto Uchiyama ◽  
Kotaro Satoh ◽  
Thomas G. McKenzie ◽  
Qiang Fu ◽  
Greg. G. Qiao ◽  
...  
Keyword(s):  
Raft Polymerization ◽  
Star Polymers ◽  
Cross Linking

Core cross-linked star polymers were synthesizedviacationic RAFT polymerization and three different approaches in combination with a radical RAFT mechanism.

scholarly journals Star polymers with acid-labile diacetal-based cores synthesized by aqueous RAFT polymerization for intracellular DNA delivery

2020 ◽  
Vol 11 (2) ◽  
pp. 344-357 ◽  
Author(s):  
Thomas J. Gibson ◽  
Peter Smyth ◽  
Mona Semsarilar ◽  
Aidan P. McCann ◽  
William J. McDaid ◽  
...  
Keyword(s):  
Low Temperature ◽  
Raft Polymerization ◽  
Star Polymers ◽  
Dna Delivery ◽  
Acid Labile

Facile low temperature aqueous heterogeneous RAFT polymerization for preparation of novel star polymers with acid-labile diacetal-based cores for DNA delivery.

Synthesis of Star Polymers using RAFT Polymerization: What is Possible?

2006 ◽  
Vol 59 (10) ◽  
pp. 719 ◽  
Author(s):  
Christopher Barner-Kowollik ◽  
Thomas P. Davis ◽  
Martina H. Stenzel
Keyword(s):  
Raft Polymerization ◽  
Star Polymers ◽  
Vinyl Pyrrolidone ◽  
Side Reactions ◽  
Radical Concentration ◽  
Reversible Addition ◽  
Polymer Architectures ◽  
Raft Agent ◽  
Poly Vinyl Pyrrolidone ◽  
Careful Design

Various pathways to generate star polymers using reversible addition–fragmentation transfer (RAFT) are discussed. Similar to other polymerization techniques, star polymers can be generated using arm-first and core-first approaches. Unique to the RAFT process is the subdivision of the core-first approach into the R-group and Z-group approaches, depending on the attachment of the RAFT agent to the multifunctional core. The mechanism of the R- and Z-group approaches are discussed in detail and it is shown that both techniques have to overcome difficulties arising from termination reactions. Termination reactions were found to broaden the molecular weight. However, these side reactions can be limited by careful design of the synthesis. Considerations include RAFT and radical concentration, number of arms, type of RAFT agent and monomer. Despite obvious challenges, the RAFT process is highly versatile, allowing the synthesis of novel polymer architectures such as poly(vinyl acetate) and poly(vinyl pyrrolidone) star polymers.

Core hyper-cross-linked star polymers from block polymer micelle precursors

2020 ◽  
Vol 11 (45) ◽  
pp. 7178-7184
Author(s):  
Jongmin Park ◽  
Stefan J. D. Smith ◽  
Colin D. Wood ◽  
Xavier Mulet ◽  
Myungeun Seo
Keyword(s):  
Star Polymers ◽  
Cross Linking ◽  
Polymer Micelle ◽  
Polymer Micelles ◽  
Block Polymer

Hyper-cross-linking of a core of block polymer micelles produces core cross-linked polymer with a spacious hyper-cross-linked core, which is solution-processible.

Doubly-responsive hyperbranched polymers and core-crosslinked star polymers with tunable reversibility

2015 ◽  
Vol 6 (45) ◽  
pp. 7871-7880 ◽  
Author(s):  
Sunirmal Pal ◽  
Megan R. Hill ◽  
Brent S. Sumerlin
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Star Polymers ◽  
Hyperbranched Polymers ◽  
Reversible Addition ◽  
Redox Responsive

Thermo- and redox-responsive hyperbranched copolymers were prepared by statistical copolymerization of N-isopropylacrylamide (NIPAM) and N,N′-bis(acryloyl)cystamine (BAC) by reversible addition–fragmentation chain transfer (RAFT) polymerization.

Synthesis of Functional Core, Star Polymers via RAFT Polymerization for Drug Delivery Applications

2012 ◽  
Vol 33 (9) ◽  
pp. 760-766 ◽  
Author(s):  
Jinna Liu ◽  
Hien Duong ◽  
Michael R. Whittaker ◽  
Thomas P. Davis ◽  
Cyrille Boyer
Keyword(s):  
Drug Delivery ◽  
Raft Polymerization ◽  
Star Polymers ◽  
Drug Delivery Applications

Analysis of Thiol-sensitive Core-cross-linked Polymeric Micelles Carrying Nucleoside Pendant Groups using 'On-line' Methods: Effect of Hydrophobicity on Cross-linking and Degradation

2011 ◽  
Vol 64 (6) ◽  
pp. 766 ◽  
Author(s):  
Bianca M. Blunden ◽  
Donald S. Thomas ◽  
Martina H. Stenzel
Keyword(s):  
Block Copolymers ◽  
Polymeric Micelles ◽  
Raft Polymerization ◽  
Amphiphilic Block Copolymers ◽  
Cross Linking ◽  
Copolymer Composition ◽  
Reversible Addition ◽  
On Line ◽  
Styrene Content ◽  
Poly Ethylene

Amphiphilic block copolymers were prepared via reversible–addition fragmentation chain transfer (RAFT) polymerization and their synthesis, cross-linking, and degradation were studied using on-line monitoring. The focus of this work is the systematic alteration of the hydrophobic block using copolymers based on 5′-O-methacryloyluridine (MAU) and styrene at different compositions to determine the effect of the copolymer composition on the properties of the micelle. A poly(poly(ethylene glycol) methyl ether methacrylate) (PEGMA) macroRAFT agent was chain extended with a mixture of styrene and MAU. In both systems, an increasing fraction of styrene was found to reduce the rate of polymerization, but the functionality of the RAFT system was always maintained. The amphiphilic block copolymers were dialyzed against water to generate micelles with sizes between 17 and 25 nm according to dynamic light scattering (DLS). Increasing styrene content lead to smaller micelles (determined by DLS and transmission electron microscopy) and to lower critical micelle concentrations, which was measured using surface tensiometry. The micelles were further stabilized via core-cross-linking using bis(2-methacroyloxyethyl) disulfide as crosslinker. NMR analysis revealed a faster consumption of crosslinker with higher styrene content. These stable cross-linked micelles were investigated regarding their ability to degrade in the presence of dithiothreitol as a model reductant. Increasing the styrene content resulted in a faster degradation of the cross-linked micelles into unimers.

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