Temperature programed photo-induced RAFT polymerization of stereo-block copolymers of poly(vinyl acetate)

2017 ◽  
Vol 8 (39) ◽  
pp. 6024-6027 ◽  
Author(s):  
Na Li ◽  
Dongdong Ding ◽  
Xiangqiang Pan ◽  
Zhengbiao Zhang ◽  
Jian Zhu ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Vinyl Acetate ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Molecular Weights

Stereo-triblock copolymers of poly(vinyl acetate) are synthesized with controlled molecular weights based on a temperature-programed photo-induced RAFT in HFIP.

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.

TPE-containing amphiphilic block copolymers: synthesis and application in the detection of nitroaromatic pollutants

2020 ◽  
Vol 11 (45) ◽  
pp. 7244-7252
Author(s):  
Shiyuan Zhou ◽  
Peiyang Gu ◽  
Haibo Wan ◽  
Yutao Zhu ◽  
Anna Wang ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Fluorescence Detection ◽  
Raft Polymerization ◽  
Nitroaromatic Compounds ◽  
Amphiphilic Block Copolymers ◽  
Molecular Weights

Two AIE block copolymers termed P1 and P2 bearing TPE and PEG-based chains were synthesized with moderate molecular weights and narrow PDIs via RAFT polymerization. Both P1 and P2 can be used in the fluorescence detection of nitroaromatic compounds (NACs) and cell images.

scholarly journals Facile synthesis of fluorescent ABA type amphiphilic triblock copolymers via RAFT polymerization and their aggregation behavior in a selective solvent

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Junwei Fu ◽  
Zhenping Cheng ◽  
Nianchen Zhou ◽  
Jian Zhu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chain Transfer ◽  
Uv Light ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Facile Synthesis ◽  
Selective Solvent ◽  
Molecular Weights ◽  
Aggregation Behaviour ◽  
Transmission Electron

AbstractWell-defined naphthalene end-capped poly(styrene)-block-poly(Nisopropyl- acrylamide)-block-poly(styrene) (PS-b-PNIPAM-b-PS) amphiphilic triblock copolymers with different molecular weights and block copolymer compositions were successfully prepared via consecutive reversible additionfragmentation chain transfer (RAFT) polymerizations using a novel RAFT reagent, S,S'-bis(1-naphthylmethyl) trithiocarbonate (BNTTC). The aggregation behaviour of the prepared PS-b-PNIPAM-b-PS in water/DMF mixture was studied by transmission electron microscopy (TEM). The effect of the copolymer concentration, PNIPAM block length and the irradiation of UV-light on the sizes and morphologies of micelles were also investigated.

Synthesis of RAFT Block Copolymers in a Multi-Stage Continuous Flow Process Inside a Tubular Reactor

2013 ◽  
Vol 66 (2) ◽  
pp. 192 ◽  
Author(s):  
Christian H. Hornung ◽  
Xuan Nguyen ◽  
Stella Kyi ◽  
John Chiefari ◽  
Simon Saubern
Keyword(s):  
Block Copolymers ◽  
Continuous Flow ◽  
Raft Polymerization ◽  
Tubular Reactor ◽  
Organic Media ◽  
Vinyl Monomers ◽  
Flow Process ◽  
Molecular Weights ◽  
Multi Stage ◽  
Polymerization Method

This work describes a multi-stage continuous flow polymerisation process for the synthesis of block copolymers using the RAFT polymerization method. The process retains all the benefits and versatility of the RAFT method and has been adapted for a series of monomer combinations, including acrylates, acrylamides, and vinyl monomers. It resulted in polymers with molecular weights between 13500 and 34100 g mol–1, and dispersities typically between 1.21 and 1.58. Different architectures were prepared (including combinations of hydrophilic and hydrophobic blocks) which are soluble in a range of different solvents including aqueous and organic media.

scholarly journals Towards a Polymer-Brush-Based Friction Modifier for Oil

2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Tobias A. Gmür ◽  
Joydeb Mandal ◽  
Juliette Cayer-Barrioz ◽  
Nicholas D. Spencer
Keyword(s):  
Block Copolymers ◽  
Raft Polymerization ◽  
Film Formation ◽  
Polymer Brush ◽  
Friction Reduction ◽  
Friction Modifier ◽  
Molecular Weights ◽  
Sliding Surfaces ◽  
Reversible Addition ◽  
Anchoring Groups

AbstractTo meet the need for oil-compatible friction modifier additives that can significantly reduce energy consumption in the boundary-lubrication regime, a macromolecular design approach has been taken. The aim was to produce a lubricious polymer film on the sliding surfaces. A series of readily functionalizable block copolymers carrying an oleophilic poly(dodecyl methacrylate) block and a functionalizable poly(pentafluorophenyl methacrylate) block of various lengths was synthesized by means of reversible addition-fragmentation chain-transfer (RAFT) polymerization. The poly(pentafluorophenyl methacrylate) block was used to attach surface-active nitrocatechol anchoring groups to the polymer. The friction-reduction properties of these polymers were assessed with 0.5 wt% solutions in hexadecane by means of rolling-sliding macroscopic tribological tests. Block copolymers with roughly equal block lengths and moderate molecular weights were significantly more effective at friction reduction than all other architectures investigated. They also displayed lower friction coefficients than glycerol monooleate—a commercially used additive. The film-formation ability of these polymers was examined using a quartz-crystal microbalance with dissipation (QCM-D), by monitoring their adsorption onto an iron oxide-coated QCM crystal. The polymer with highest lubrication efficiency formed a thin film of ~ 17 nm thickness on the crystal, indicating the formation of a polymer brush. Interferometric rolling-sliding experiments with the same polymer showed a separating film thickness of ~ 20 nm, which is consistent with the QCM-D value, bearing in mind the compression of the adsorbed layers on the two sliding surfaces during tribological testing. Graphical Abstract

Chiroptical Properties of Homopolymers and Block Copolymers Synthesized from the Enantiomeric Monomers N-Acryloyl-L-Alanine and N-Acryloyl-D-Alanine Using Aqueous RAFT Polymerization

2006 ◽  
Vol 59 (10) ◽  
pp. 749 ◽  
Author(s):  
Brad S. Lokitz ◽  
Jonathan E. Stempka ◽  
Adam W. York ◽  
Yuting Li ◽  
Hitesh K. Goel ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Raft Polymerization ◽  
Mirror Image ◽  
Cd Spectra ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Biomimetic Polymers ◽  
Reversible Addition ◽  
Weight Distributions ◽  
Analogous Model

Chiral homo- and block copolymers based on the enantiomeric monomers N-acryloyl-l-alanine (ALAL) and N-acryloyl-d-alanine (ADAL) were prepared directly in water using controlled reversible addition–fragmentation chain transfer (RAFT) polymerization. The polymerization of the chiral monomers proceeded in a controlled fashion producing the respective homopolymers, block copolymers, and a statistical copolymer with targeted molecular weights and narrow molecular weight distributions. The chiroptical activity of these biomimetic polymers and their analogous model compounds was investigated using circular dichroism (CD). P(ALAL) and P(ADAL) were shown to be optically active exhibiting mirror image CD spectra. In addition, statistical and enantiomeric block copolymers prepared at 1:1 stochiometric ratios exhibited virtually no optical activity.

Synthesis of N-vinylcarbazole–N-vinylpyrrolidone amphiphilic block copolymers by xanthate-mediated controlled radical polymerization

2010 ◽  
Vol 88 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Chih-Feng Huang ◽  
Jeong Ae Yoon ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Block Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Controlled Radical Polymerization ◽  
Amphiphilic Block Copolymers ◽  
Force Microscopy ◽  
Molecular Weights ◽  
Atomic Force ◽  
Reversible Addition ◽  
Mode Atomic Force Microscopy

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.

scholarly journals Towards a Polymer-Brush-Based Friction Modifier for Oil

2021 ◽  
Author(s):  
Tobias A. Gmür ◽  
Joydeb Mandal ◽  
Juliette Cayer-Barrioz ◽  
Nicholas D. Spencer
Keyword(s):  
Iron Oxide ◽  
Block Copolymers ◽  
Raft Polymerization ◽  
Film Formation ◽  
Polymer Brush ◽  
Friction Reduction ◽  
Friction Modifier ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Anchoring Groups

Abstract In the search for new, oil-compatible friction-modifier additives that can significantly reduce energy consumption by reducing the friction in the boundary-lubrication regime, a macromolecular-design approach has been taken. This involved the synthesis of a series of readily functionalizable block copolymers carrying an oleophilic poly(lauryl methacrylate) block and a functionalizable poly(pentafluorophenyl methacrylate) block of various lengths by means of reversible addition-fragmentation chain-transfer (RAFT) polymerization. The poly(pentafluorophenyl methacrylate) block was used to attach surface-active nitro-catechol anchoring groups to the polymer. The friction-reduction properties of these polymers were assessed using 0.5 wt.% solutions in hexadecane using rolling-sliding macroscopic tribological tests. Block copolymers with roughly equal block lengths and moderate molecular weights were significantly more effective at friction reduction than all other architectures investigated. They also displayed lower friction coefficients than glycerol monooleate, a commercially used additive. The film formation ability of these polymers was examined using a quartz-crystal microbalance with dissipation (QCM-D), by monitoring their adsorption onto an iron-oxide coated QCM crystal. The polymer with highest lubrication efficiency formed a thin film of ∼17 nm thickness on the iron-oxide coated QCM crystal, consistent with the formation of a polymer brush. Interferometric rolling-sliding experiments with the same polymer showed a separating film thickness of ∼20 nm, which is consistent with the QCM-D value, bearing in mind the compression of the adsorbed layers on the two sliding surfaces during tribological testing.

Preparation of ABC triblock copolymers of N-alkyl substituted acrylamides by RAFT polymerization

2007 ◽  
Vol 85 (6) ◽  
pp. 407-411 ◽  
Author(s):  
Ya Cao ◽  
X X Zhu
Keyword(s):  
Block Copolymers ◽  
Propionic Acid ◽  
Chain Transfer ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Synthetic Pathway ◽  
Abc Triblock Copolymers ◽  
Alkyl Groups ◽  
Reversible Addition ◽  
Acrylamide Monomers

Reversible addition-fragmentation chain transfer (RAFT) polymerization of N-alkyl substituted acrylamides has been carried out by the use of a trithiocarbonate (2-dodecylsulfanylthiocarbonyl-sulfanyl-2-methyl propionic acid) as the RAFT reagent. The N-alkyl groups of the acrylamide monomers are important in the RAFT process. N-alkyl monosubstituted polyacrylamides are found to be active macro-chain transfer agents, while N,N-disubstituted monomers can react easily with them to form a sequent block. We have designed a synthetic pathway to successfully prepare ABC triblock copolymers of N-alkyl substituted acrylamides with low polydispersities (PDI < 1.20) by a three-step RAFT polymerization process.Key words: block copolymers, RAFT polymerization, N-alkyl substituted acrylamides, thermosensitive polymers.

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