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.

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.

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.

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.

Synthesis and Characterization of well Defined Polychloroprene by RAFT Polymerization

2013 ◽  
Vol 787 ◽  
pp. 241-244
Author(s):  
Jia Hui ◽  
Yan Shi ◽  
Zhi Feng Fu
Keyword(s):  
Molecular Weight ◽  
Raft Polymerization ◽  
Average Molecular Weight ◽  
Reaction Times ◽  
Monomer Conversion ◽  
H Nmr ◽  
Molecular Weight Distributions ◽  
Reversible Addition ◽  
Raft Agent ◽  
Active Nature

Well defined polychloroprene has been synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization with 2-(ethoxycarbonyl) prop-2-yl dithiobenzoate (EPDTB) as RAFT agent, AIBN as initiator, Chloroprene as monomer. Polymerization with two different feed ratios of monomer to RAFT agent were carried out. The sampling products at different reaction times were characterized using GPC and 1H-NMR. The GPC results demonstrated the molecular weight distributions (Mw/Mn) were narrow, and the number average molecular weight (Mn) was developed linearly with monomer conversion. All the characteristic signals of polychloroprene with the EPDTB as terminal groups were clearly observed in the 1H-NMR spectrum. In addition, the chain-extended polymers were also obtained successfully using the macro-RAFT agent, which indicated the active nature of the chain end.

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).

Polymerization of styrene using 1,1,2,2-tetraphenyl-1,2- ethanediol as initiator in the presence of 2,2,6,6-tetramethyl- 1-piperidinyloxy

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Gang Wang ◽  
Xiulin Zhu ◽  
Dijun Hu ◽  
Zhengping Cheng ◽  
Jian Zhu
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Bulk Polymerization ◽  
Polymerization Rate ◽  
First Order ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
End Groups

Abstract The bulk polymerization of styrene using 1,1,2,2-tetraphenyl-1,2-ethanediol as initiator in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) was investigated. The results show that polymerization proceeded in a controlled/ ’living’ way, i.e., polymerization rate is first order with respect to monomer concentration. Molecular weights increase linearly with conversion and molecular weight distributions are relatively low (Mw/Mn = 1.10 - 1.35). Well-defined polystyrenes with α-hydrogen and TEMPO end groups were obtained.

ATRP Synthesis and Characterization of μ,αω-allyl-terminated Macromonomers as Precursors for End-linked Gels and Hydrogels

2003 ◽  
Vol 774 ◽  
Author(s):  
Lucy Vojtova ◽  
Nicholas J. Turro ◽  
Jeffrey T. Koberstein
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Monomer Conversion ◽  
Catalyst System ◽  
Linear Increase ◽  
Butyl Methacrylate ◽  
First Order Kinetics ◽  
Significant Difference ◽  
Ft Ir

AbstractSynthesis of α,ω-allyl-terminated telechelic macromonomers based on poly(tert-butyl methacrylate) (poly(t-BMA)) and poly(methacrylic acid) (poly(MAA)) was studied with the aim of preparing end-linked gels and hydrogels. Low molecular weight α-allyl-terminated poly(t-BMA) macromonomers with narrow polydispersities (Mw/Mn = 1.16) were synthesized via controlled atom transfer radical polymerization (ATRP) using a Cu(I)Br/N,N,N',N',N',N'-hexamethyltriethylenetetraamine catalyst system in conjunction with an allyl-2-bromoisobutyrate as the functional initiator. The polymerizations exhibited a linear increase of molecular weight in direct proportion to the monomer conversion and first-order kinetics with respect to monomer concentration. No significant difference was found between using polar or non-polar solvents (tetrahydrofuran or benzene, respectively). Optimization of reaction conditions to obtain the highest degree of active terminal bromine is discussed. Quenching the ATRP reaction with allyltributyltin yielded α,ω-allyl-terminated poly(t-BMA) macromonomers by replacing the terminal bromine with ω-allyl functional group. Poly(MAA) macromonomers were prepared by deprotection of the tert-butyl group from α,ω-allyl-terminated poly(t-BMA) macromonomers using concentrated trifluoroacetic acid at room temperature. Successful synthetic steps were confirmed by 1H NMR, FT-IR and MALDI-TOF MS analyses. The α,ω-allyl-terminated macromonomers were proven to be candidates for further polymerization by forming end-linked, non-soluble gels.

Synthesis of Well-defined Carbazole Group Labelled Polymer via RAFT Polymerization and Study on the Optical Properties

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Di Zhou ◽  
Xiulin Zhu ◽  
Jian Zhu ◽  
Lihua Hu ◽  
Zhenping Cheng
Keyword(s):  
Optical Properties ◽  
Raft Polymerization ◽  
Chain Extension ◽  
Dimethyl Formamide ◽  
Coupling Scheme ◽  
H Nmr ◽  
Azo Polymer ◽  
Raft Agent ◽  
Carbazole Group ◽  
Polymerization Conditions

AbstractBenzyl 9H-carbazole-9-carbodithioate (BCC) was synthesized and characterized. The single-crystal structure of BCC was first reported. The RAFT polymerizations of styrene and acrylates using BCC as the RAFT agent under conventional polymerization conditions were investigated. The results showed that the BCC was an effective RAFT agent for the polymerizations of styrene and acrylates. The well-controlled polymers were labelled with carbazole group, which was confirmed by 1H NMR and the chain extension of the obtained polymer. Azo modified poly(methyl acrylate) (PMA) was synthesized through a postpolymerization azo-coupling scheme. The optical properties of obtained polymer were also characterized. The results showed that the carbazole group labelled polymer exhibited fluorescence and the azo polymer exhibited UV absorption behaviour in N,N-dimethyl formamide (DMF).

Effect of stabilizer concentration and controller structure and composition on polymerization rate and molecular weight development in RAFT polymerization of styrene in supercritical carbon dioxide

Polymer ◽  
2009 ◽  
Vol 50 (21) ◽  
pp. 5024-5030 ◽  
Author(s):  
Gabriel Jaramillo-Soto ◽  
Pedro R. García-Morán ◽  
Francisco J. Enríquez-Medrano ◽  
Hortensia Maldonado-Textle ◽  
Martha E. Albores-Velasco ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Molecular Weight ◽  
Supercritical Carbon Dioxide ◽  
Raft Polymerization ◽  
Polymerization Rate ◽  
Stabilizer Concentration ◽  
Supercritical Carbon

scholarly journals Study on MMA and BA Emulsion Copolymerization Using 2,4-Diphenyl-4-methyl-1-pentene as the Irreversible Addition–Fragmentation Chain Transfer Agent

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 80
Author(s):  
Zuxin Zhang ◽  
Daihui Zhang ◽  
Gaowei Fu ◽  
Chunpeng Wang ◽  
Fuxiang Chu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Tensile Properties ◽  
Chain Transfer ◽  
Monomer Conversion ◽  
Degree Of Polymerization ◽  
Polymerization Rate ◽  
Chain Transfer Agent ◽  
Regulation Mechanism ◽  
Transfer Coefficients ◽  
Emulsion Copolymerization

As a chain transfer agent, 2,4-diphenyl-4-methyl-1-pentene (αMSD) was first introduced in the emulsion binary copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA) based on an irreversible addition–fragmentation chain transfer (AFCT) mechanism. The effects of αMSD on molecular weight and its distribution, the degree of polymerization, polymerization rate, monomer conversion, particle size, and tensile properties of the formed latexes were systematically investigated. Its potential chain transfer mechanism was also explored according to the 1H NMR analysis. The results showed that the increase in the content of αMSD could lead to a decline in molecular weight, its distribution, and the degree of polymerization. The mass percentage of MMA in the synthesized polymers was also improved as the amounts of αMSD increased. The chain transfer coefficients of αMSD for MMA and BA were 0.62 and 0.47, respectively. The regulation mechanism of αMSD in the emulsion polymerization of acrylates was found to be consistent with Yasummasa’s theory. Additionally, monomer conversion decreased greatly to 47.3% when the concentration of αMSD was higher than 1 wt% due to the extremely low polymerization rate. Moreover, the polymerization rate was also decreased probably due to the desorption and lower reactivity of the regenerative radicals from αMSD. Finally, the tensile properties of the resulting polyacrylate films were significantly affected due to the presence of αMSD.

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