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).

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 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.

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.

Dendrimers as Scaffolds for Reversible Addition Fragmentation Chain Transfer (RAFT) Agents: a Route to Star-Shaped Block Copolymers

2005 ◽  
Vol 58 (6) ◽  
pp. 483 ◽  
Author(s):  
Xiaojuan Hao ◽  
Eva Malmström ◽  
Thomas P. Davis ◽  
Martina H. Stenzel ◽  
Christopher Barner-Kowollik
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Butyl Acrylate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Star Polymers ◽  
Size Exclusion ◽  
Chain Extension ◽  
Reversible Addition ◽  
Star Block Copolymers

Star-shaped block copolymers of styrene and n-butyl acrylate having three, six, and twelve pendent arms were successfully synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Dendritic cores (based on 1,1,1-trimethylolpropane) of generation 0, 1, and 2 have been functionalized with 3-benzylsulfanylthiocarbonylsulfanylpropionic ester groups and have subsequently been employed to mediate the polymerization of styrene and n-butyl acrylate to generate macro-star-RAFT agents as starting materials for chain extension. The chain extension of the macro-star-RAFT agents with either styrene or n-butyl acrylate by bulk free radical polymerization at 60°C gives narrowly distributed polymer (final polydispersities close to 1.2) increasing linearly in molecular weight with increasing monomer-to-polymer conversion. However, with an increasing number of arms (i.e., when going from three- to twelve-armed star polymers), the chain extension becomes significantly less efficient. The molecular weight of the generated block copolymers was assessed using 1H NMR spectroscopy as well as size exclusion chromatography calibrated with linear polystyrene standards. The hydrodynamic radius, Rh, of the star block copolymers as well as the precursor star polymers was determined in tetrahydrofuran by dynamic light scattering (90°) at 25°C. Interestingly, the observed Rh–Mn relationships indicate a stronger dependence of Rh on Mn for poly(butyl acrylate) stars than for the corresponding styrene polymers. Rh increases significantly when the macro-star-RAFT agent is chain extended with either styrene or n-butyl acrylate.

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 of Polystyrene-B-Poly(Ethylene Oxide)monomethyl Ethermethacrylate Block Copolymers and its Self-Assembly in Aqueous Solution

2011 ◽  
Vol 284-286 ◽  
pp. 769-772
Author(s):  
Qian Qian You ◽  
Pu Yu Zhang
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Self Assembly ◽  
Chain Transfer ◽  
Functional Group ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Ft Ir ◽  
A Chain

The block copolymer of PSt-b-POEOMA with the end of -COOH functional group has been synthesized by reversible addition fragmentation chain-transfer (RAFT) using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as a chain transfer agent. The architectures of the copolymers were confirmed by FT-IR and 1HNMR spectra. GPC analysis was used to estimate the molecular weight and the molecular weight distribution of the copolymers. Meanwhile, The nanostructures of the block copolymers PSt-b-POEOMA micelles formed in aqueous solution were observed by transmission electron microscopy (TEM) and dynamic light scattering (DLS).

Chiral Recognition of L-Carnitine Using Surface Molecularly Imprinted Microspheres via RAFT Polymerization

2014 ◽  
Vol 884-885 ◽  
pp. 33-36 ◽  
Author(s):  
Lin Tong Hou ◽  
Jiao Jiao Chen ◽  
Hong Jun Fu ◽  
Xin Lei Fu
Keyword(s):  
Experimental Data ◽  
Chiral Recognition ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Isothermal Adsorption ◽  
Molecularly Imprinted ◽  
Reversible Addition ◽  
Ft Ir ◽  
Molecularly Imprinted Microspheres

A molecularly imprinted microsphere (MIPs) was prepared successfullyviasurface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization. Characterization of the obtained MIPs was achieved by FT-IR and TGA. The isothermal adsorption and chiral separation experiments of MIPs on L-Carnitine were investigated. Compared with non-imprinted microsphere (NMIPs) adsorbent, MIPs showed faster adsorption rate and stronger adsorption capacity for L-Carnitine. Equilibrium experimental data of MIPs fitted the Langmuir isotherm better. Furthermore, the MIPs also exhibited enantioselectivity for L-Carnitine through the resolution experiment.

Bioconjugation of papain with poly(N-vinylpyrrolidone): NMR characterization and study of its enzymatic activity

2021 ◽  
Vol 99 (1) ◽  
pp. 10-17
Author(s):  
L.E. Verduzco ◽  
Ana L. García-Pérez ◽  
Ramiro Guerrero-Santos ◽  
Antonio Ledezma-Pérez ◽  
Jorge Romero-García ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Chain Transfer ◽  
Gel Permeation Chromatography ◽  
Acid Group ◽  
H Nmr ◽  
Reversible Addition ◽  
Nmr Characterization ◽  
Vis Spectroscopy ◽  
C Nmr

A poly(vinylpyrrolidone) end-functionalized with a carboxylic acid group (PVP–CO2H) was synthesized by reversible addition-fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) polymerization mediated by 4-(O-ethylxanthyl)methyl benzoic acid. The molecular weight of the as-synthesized PVP–CO2H was estimated through UV–vis spectroscopy (Mn(UV–vis) = 7322 g/mol), gel permeation chromatography (GPC) (Mn(GPC) = 8670 g/mol), and 1H NMR, (Mn(NMR) = 8207 g/mol). The values obtained were close with the theoretical molecular weight (Mn(th) = 7925 g/mol). Subsequently, the preformed PVP–CO2H was activated to produce N-succinimidyl poly(vinylpyrrolidone) (PVP–NHS). This precursor was covalently coupled to papain to produce bioconjugate PVP–papain. The functional group modifications in the PVP chain-end were observed by the variations in the chemical shift values by 1H and 13C NMR and FTIR analysis at each step of the synthesis. The molecular weight of the PVP–papain was obtained by SEC–HPLC and suggests that, on average, four or five chains of PVP–CO2H were attached to one papain molecule. Compared with papain, the PVP–papain exhibited significantly improved catalytic activity, pH, and thermal stability. Additionally, the storage studies showed that the catalytic activity of PVP–papain was about 79% versus the native enzyme (29%), and this activity was maintained even when it was stored for 25 days.

Living free radical polymerization of styrene with 2-cyanoprop-2-yl dithionaphthalate as RAFT agent

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Zhu Jian ◽  
Zhu Xiulin ◽  
Zhou Di ◽  
Chen Jianying
Keyword(s):  
Molecular Weight ◽  
Reaction Temperature ◽  
Raft Polymerization ◽  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Monomer Conversion ◽  
Bulk Polymerization ◽  
Polymerization Rate ◽  
Chain Extension ◽  
Raft Agent

Abstract The reversible addition-fragmentation chain transfer (RAFT) bulk polymerization of styrene was studied using 2-cyanoprop-2-yl dithionaphthalate (CPDN) as RAFT agent in the presence or absence of 2,2’-azoisobutyronitrile (AIBN). The results of both thermally and AIBN-initiated styrene (St) polymerizations show that St can be polymerized in a controlled way using CPDN as RAFT agent; i.e., the polymerization rate is first order with respect to monomer concentration, and molecular weight increases linearly with monomer conversion. The molecular weights obtained from gel permeation chromatography are close to the theoretical values and molecular weight distributions are relatively narrow (Mw/Mn < 1.2). It is confirmed by chain extension reaction that the polymer prepared via RAFT polymerization can be used as a macroRAFT agent. The effects of reaction temperature and mole ratios [St]0/[CPDN]0/[AIBN]0 on the polymerization were investigated. The results indicate that the reaction temperature has a positive effect on the polymerization rate, but little effect on molecular weight and molecular weight distribution, and the optimum mole ratios were found to be [CPDN]0/[AIBN]0 > 4/3 and [St]0/[CPDN]0 < 800.

Using Reversible Addition-Fragmentation Chain Transfer Polymerization to Synthesize Well-Defined Polymer

2013 ◽  
Vol 781-784 ◽  
pp. 415-418
Author(s):  
Shou Juan Bian ◽  
Ying Juan Fu ◽  
Meng Hua Qin
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Reaction Conditions ◽  
Reversible Addition ◽  
Complex Architectures ◽  
Versatile Tool ◽  
Green Polymers ◽  
Controlled Structure ◽  
Chain Transfer Polymerization

As an effective and versatile tool for production of functional polymer, RAFT polymerization has been successfully applied to the polymerization of block copolymers and other polymers of complex architectures with precisely controlled structure, molecular weight, and polydispersity. It has the ability to control polymerization of most monomers and has fine compatibility with reaction conditions. The present article summarized some of the features of the RAFT process, and reviewed the recent advances in the production of green polymers.

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