Synthesis of azobenzene-centered (co)polymers via reversible addition-fragmentation chain transfer (RAFT) polymerization

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Yu Liping ◽  
Zhu Jian ◽  
Cheng Zhenping ◽  
Zhang Zhengbiao ◽  
Zhang Wei ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Dimethyl Formamide ◽  
Reversible Addition ◽  
Raft Agent ◽  
Pentablock Copolymers ◽  
Ft Ir

Abstract An azobenzene-based dithiocarbamate, 4,4'-bis[2-(carbazole-N-dithio formatyl)-2-methyl-propionatyl]-azobenzene (CDMPA), was synthesized and used as the chain transfer agent (CTA) for reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene in anisole solution. Well-defined azobenzene-centered and carbazole-ended polystyrene (PS) with well-controlled molecular weight (Mn) and narrow molecular weight distributions (Mw/Mn) was obtained. The good agreement between the theoretical molecular weight (Mn,th) and the 1H NMR determined molecular weight (Mn,NMR) indicated that most of the polymer chains contained an azo-functional center-group end-capped with the carbazole moieties, which were derived from the RAFT agent. The obtained polystyrene (PS) showed a strong ultraviolet absorption in tetrahydrofuran (THF) and emitted fluorescence after excited by UV-irradiation in N,N’-dimethyl formamide (DMF) solutions. The PS was used as the macro-RAFT agent to carry out the polymerization of methyl acrylate (MA) and N-isopropylacrylamide (NIPAAM). Triblock copolymers (PMA-b-PS-b-PMA), and pentablock copolymers (PNIPAAM-b-PMA-b-PS-b-PMA-b-PNIPAAM) were obtained, respectively. These copolymers were characterized by gel permeation chromatography (GPC), FT-IR spectroscopy and NMR spectroscopy.

scholarly journals Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization of Poly(ethylmethacrylate) with Pendant Carbazole Groups

KIMIKA ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 41-50
Author(s):  
Shienna Marie Pontillas ◽  
Florentino C. Sumera ◽  
Rigoberto C. Advincula
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Chain Extension ◽  
Conversion Characteristic ◽  
Reversible Addition ◽  
Ft Ir ◽  
Carbazole Group

Carbazole containing polymers have captured the interest of researchers for use in optoelectronics. For an important material to exhibit its optoelectronic properties intrinsic uniformity in the molecular level is required. Thus, a monomer of ethyl methacrylate with pendant carbazole group was synthesized and polymerized via Reversible Addition-Fragmentation Chain Transfer (RAFT) to produce polymers with controlled molecular weight distribution and narrow polydispersity index (PDI). This method of polymerization was compared with that of free radical polymerization by gel permeation chromatography (GPC). The RAFT’s polymerization kinetics was observed to follow a plot of number average molecular weight (Mn) versus % conversion, characteristic of living polymerization. It was also shown to possess polymer chain extension capability. The structure of the monomer and the polymers were characterized by Fourier-Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR).

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.

scholarly journals Graft Copolymerization of Styrene from Poly(vinyl alcohol) via RAFT Process

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Gholam Ali Koohmareh ◽  
Morteza Hajian ◽  
Hazhir Fallahi
Keyword(s):  
Vinyl Alcohol ◽  
Raft Polymerization ◽  
Gel Permeation Chromatography ◽  
Poly Vinyl Alcohol ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Reversible Addition ◽  
Raft Agent ◽  
Ft Ir ◽  
Hydrolysis Of

Polystyrene, PS, was grafted from poly(vinyl alcohol), PVA, backbone by reversible addition-fragmentation chain transfer (RAFT) polymerization. The hydroxyl groups of the PVA were converted into aromatic dithioester RAFT agent and polymerization began in the presence of this agent. The structure of compounds was confirmed by FT-IR and1HNMR spectroscopy. The graft copolymer was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Grafted polystyrene chains were cleaved from the PVA backbone by acidic hydrolysis of the PVA-g-PS, and its polydispersity index, PDI, was determined by gel permeation chromatography (GPC) showing narrow molecular weight distribution.

scholarly journals CONSTRUCTING POLYSTYRENE BRUSHES ON TIO2 NANOPARTICLES BY IN SITU REVERSIBLE ADDITION FRAGMENTATION CHAIN TRANSFER POLYMERIZATION

2018 ◽  
Vol 54 (1A) ◽  
pp. 292
Author(s):  
Long Giang Bach
Keyword(s):  
Tio2 Nanoparticles ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Average Particle Size ◽  
Average Particle ◽  
Tio2 Nps ◽  
Reversible Addition ◽  
Raft Agent ◽  
Ft Ir ◽  
Chain Transfer Polymerization

This paper presents the preparation of polystyrene functionalized TiO2 nanoparticles using the reversible addition fragmentation chain transfer (RAFT) polymerization. The surface of TiO2 NPs with an average particle size of about 5 nm was modified by S-benzyl S’-trimethoxysilylpropyltrithiocarbonate in order to obtain the RAFT agent functionalized TiO2 NPs (TiO2-RAFT). Subsequently, styrene was radically polymerized through the immobilized RAFT agent on the silica surface, in the presence of 2,2’-azobisisobutylnitrile (AIBN) as an initiator, to achieve the TiO2-g-PS nanocomposite. The characteristics of the as-synthesized nanocomposite were determined using FT-IR, EDX, XPS, TGA, XRD, TEM and SEM analyses.

Preparation and Characterization of PMMA-b-PDMAEMA/Polysulfone Composite Membranes by RAFT Polymerization and their Permeation Performance of Carbon Dioxide

2011 ◽  
Vol 284-286 ◽  
pp. 1717-1723 ◽  
Author(s):  
Jiang Nan Shen ◽  
Yun Fei Ye ◽  
Gan Ning Zeng ◽  
Jun Hong Qiu
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Gel Permeation Chromatography ◽  
Composite Membranes ◽  
Reversible Addition ◽  
Composition And Structure ◽  
Gel Permeation ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

PMMA-b-PDMAEMA/polysulfone composite membranes for CO2separation was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization techniques. The chemical composition and structure of the polymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), and molecular weight and its distribution were measured by Gel permeation chromatography (GPC). CO2permeation performance of the PMMA-b-PDMAEMA/ polysulfone composite membranes was test. The results showed that the resulted composited membrane posses good permeation performance for CO2.

scholarly journals Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1164
Author(s):  
Angeliki Chroni ◽  
Thomas Mavromoustakos ◽  
Stergios Pispas
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymeric Nanocarriers ◽  
Reversible Addition ◽  
2D Noesy ◽  
Drug Nanocarriers ◽  
Glycol Methyl Ether ◽  
Different Molecular Weight

The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (Mw) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA30-b-POEGA70 and PnBA27-b-POEGA73 (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA27-b-POEGA73 micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA30-b-POEGA70 + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA30-b-POEGA70 and PnBA27-b-POEGA73 micelles.

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.

Effect of silica nanoparticle loading and surface modification on the kinetics of RAFT polymerization

2012 ◽  
Vol 32 (1) ◽  
Author(s):  
Mehdi Salami-Kalajahi ◽  
Vahid Haddadi-Asl ◽  
Farid Behboodi-Sadabad ◽  
Saeid Rahimi-Razin ◽  
Hossein Roghani-Mamaqani
Keyword(s):  
Molecular Weight ◽  
Surface Modification ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Silica Nanoparticle ◽  
Maximum Level ◽  
Silica Content ◽  
Considerable Change ◽  
Polymerization Rate ◽  
Raft Agent

Abstract S-(thiobenzoyl)thioglycolic acid was used to synthesize poly(methyl methacrylate) via reversible addition-fragmentation chain transfer (RAFT) polymerization. To study the polymerization kinetics, in situ polymerization reactions were performed with different loading of nanoparticles. To investigate the effect of surface modification on the poly­merization kinetics, similar reactions were performed with 3-methacryloxypropyldimethylchlorosilane-modified nanoparticles. Conversion, reaction rate, molecular weight and polydispersity index (PDI) were monitored during poly­merization. According to results, pseudo-first order kinetics is achieved, but the rate constant of chain transfer reaction to the RAFT agent (Ctr) has a very small value. Adding nanoparticles causes no considerable change in the kinetic curves, while there is an optimum value for nanoparticles loading in which the polymerization rate reaches its maximum level. A similar trend is observed for molecular weight; however, increasing silica content results in an increase in PDI values. In comparison with pristine silica nanoparticles, the polymerization rate increases slowly in the case of modified particles. Also, molecular weight and PDI for free and graft chains are studied separately. The molecular weight of free chains increases with increasing nanoparticles loading up to 7 wt% and then decreases, while PDI values increase continually by adding nanoparticles. However, for graft chains, molecular weight and PDI values increase with increasing nanoparticle content.

EFFECT OF REVERSIBLE ADDITION-FRAGMENTATION CHAIN TRANSFER EMULSION STYRENE–BUTADIENE RUBBER ON THE PROPERTIES OF SILICA COMPOUNDS

2020 ◽  
pp. 000-000 ◽  
Author(s):  
Hyunsung Mun ◽  
Kiwon Hwang ◽  
Gwanghoon Kwag ◽  
JaeKon Suh ◽  
Duseong Ahn ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Raft Polymerization ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Narrow Molecular Weight Distribution ◽  
Reversible Addition ◽  
Raft Agent ◽  
Styrene Butadiene

ABSTRACT In recent years, solution styrene–butadiene rubber (SSBR), which has a narrow molecular weight distribution, controllable microstructure, and chain end functionality, is mainly used as base rubber for passenger car tire tread compounds. However, SSBR has a lower molecular weight than that of emulsion SBR (ESBR) because it is difficult to increase the molecular weight of SSBR. In contrast, ESBR can easily increase the molecular weight; however, it has a broad molecular weight distribution. The reversible addition-fragmentation chain transfer (RAFT) polymerization technique is applicable to the emulsion polymerization. Polymers with narrow molecular weight distributions can be obtained by the RAFT polymerization because the RAFT agent prevents the coupling reaction of the growing chain radicals. In this case, ESBR having a narrow molecular weight distribution, which is an advantage of SSBR, and a high molecular weight, which is an advantage of ESBR, can be synthesized. Therefore, we synthesized RAFT ESBR and fabricated its compounds with silica filler. We confirmed that the physical properties of the RAFT ESBR silica compound are different from those of the ESBR silica compound. In addition to the narrow molecular weight distribution of the RAFT ESBR, the trithiocarbonyl group of the RAFT agent in the RAFT ESBR chain molecules affects the physical properties.

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