Mechanism of CPDB-Mediated RAFT Polymerization of Methyl Methacrylate: Influence of Pressure and RAFT Agent Concentration

2009 ◽  
Vol 62 (11) ◽  
pp. 1484 ◽  
Author(s):  
Michael Buback ◽  
Wibke Meiser ◽  
Philipp Vana
Keyword(s):  
Methyl Methacrylate ◽  
Raft Polymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Reversible Addition ◽  
Rate Of Polymerization ◽  
Weight Distributions ◽  
Raft Agent ◽  
Successful Control ◽  
Mma Polymerization

Reversible addition–fragmentation chain transfer (RAFT) polymerizations of methyl methacrylate (MMA) in bulk at 60°C were performed at five pressures up to 200 MPa using 2-(2′-cyanopropyl)dithiobenzoate (CPDB) as RAFT agent at concentrations between 1.5 × 10–3 and 2.0 × 10–2 mol L–1. Applying high pressure during polymerization increases the rate of polymerization, but no effect on polydispersity was observed. Molecular weight distributions and average molecular weights of the final polymer indicated the successful control of MMA polymerization even at low CPDB concentrations. The slight retardation observed is adequately described by the dependence the termination rate coefficient, kt, on the chain-length.

Reversible addition fragmentation chain transfer (RAFT) polymerization of styrene in fluid CO2

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Toshihiko Arita ◽  
Sabine Beuermann ◽  
Michael Buback ◽  
Philipp Vana
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Significant Difference ◽  
Raft Agent ◽  
Successful Control ◽  
A Minor ◽  
Peak Widths

Abstract Reversible addition fragmentation chain transfer (RAFT) polymerizations of styrene in fluid CO2 have been carried out at 80°C and 300 bar using cumyl dithiobenzoate as the controlling agent in the concentration range of 3.5·10-3 to 2.1·10-2 mol/L. This is the first report on RAFT polymerization in fluid CO2. The polymerization rates were retarded depending on the employed RAFT agent concentration with no significant difference between the RAFT polymerization performed in fluid CO2 and in toluene. Full chain length distributions were analyzed with respect to peak molecular weights, indicating the successful control of radical polymerization in fluid CO2. A characterization of the peak widths may suggest a minor influence of fluid CO2 on the addition reaction of macroradicals on the dithiobenzoate group.

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.

The Use of Novel F-RAFT Agents in High Temperature and High Pressure Ethene Polymerization: Can Control be Achieved?

2007 ◽  
Vol 60 (10) ◽  
pp. 788 ◽  
Author(s):  
Markus Busch ◽  
Marion Roth ◽  
Martina H. Stenzel ◽  
Thomas P. Davis ◽  
Christopher Barner-Kowollik
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
High Temperature ◽  
Degree Of Polymerization ◽  
Molecular Weight Distributions ◽  
High Pressure High Temperature ◽  
Reversible Addition ◽  
Weight Distributions ◽  
Raft Agent ◽  
Initial Results

Simulations are employed to establish the feasibility of achieving controlled/living ethene polymerizations. Such simulations indicate that reversible addition–fragmentation chain transfer (RAFT) agents carrying a fluorine Z group may be suitable to establish control in high-pressure high-temperature ethene polymerizations. Based on these simulations, specific fluorine (F-RAFT) agents have been designed and tested. The initial results are promising and indicate that it may indeed be possible to achieve molecular weight distributions with a polydispersity being significantly lower than that observed in the conventional free radical process. In our initial trials presented here (using the F-RAFT agent isopropylfluorodithioformate), a correlation between the degree of polymerization and conversion can indeed be observed. Both the lowered polydispersity and the linear correlation between molecular weight and conversion indicate that control may in principle be possible.

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.

THE BUTYLLITHIUM-INITIATED POLYMERIZATION OF METHYL METHACRYLATE: PART II. MOLECULAR WEIGHT DISTRIBUTIONS

1963 ◽  
Vol 41 (8) ◽  
pp. 1905-1910 ◽  
Author(s):  
B. J. Cottam ◽  
D. M. Wiles ◽  
S. Bywater
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Proton Magnetic Resonance ◽  
Polymer Chains ◽  
Double Peak ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Before And After ◽  
Made In

Samples of poly (methyl methacrylate) have been made in toluene solution at −30° C with n-butyllithium initiator. Different monomer and initiator concentrations were used to obtain products of different overall molecular weights; polymerization times were varied to achieve partial as well as complete polymerization. The polymer samples were divided into fractions which were examined as to molecular weight and microstructure. It was found that the whole polymers have unusually wide molecular weight distributions which can be attributed to a combination of two narrower distributions, one of which occurs at a low and the other at a higher molecular weight region. This "double peak" phenomenon was observed for polymers at lower conversions as well as for polymers representing complete conversion of monomer. Proton magnetic resonance measurements showed that the degree of isotacticity of various fractions of a whole polymer is not the same at all molecular weights.In one case a second portion of monomer was polymerized after the complete polymerization of a first portion. Comparison of the molecular weight distribution before and after the second addition of methyl methacrylate indicated that polymer chains in all molecular weight regions, above a very low minimum value, are capable of further addition of monomer.

scholarly journals Synthesis and Characterization of Well-Defined SolubleAlq3- andZnq2-Functionalized Polymers via RAFT Copolymerization

2010 ◽  
Vol 2010 ◽  
pp. 1-7
Author(s):  
Chengchao Wang ◽  
Wei Zhang ◽  
Nianchen Zhou ◽  
Yansheng Qiu ◽  
Zhengping Cheng ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Chain Extension ◽  
Aluminium Isopropoxide ◽  
Soluble Polymers ◽  
First Order ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Reversible Addition ◽  
Weight Distributions

The reversible addition-fragmentation chain transfer (RAFT) copolymerizations of 2-((8-hydroxyquinolin-5-yl)methoxy)ethyl methacrylate (HQHEMA) with styrene (St) or methyl methacrylate (MMA) were successfully carried out in the presence of 2-cyanoprop-2-yl dithionaphthalenoate (CPDN). The polymerization behaviors showed the typical living natures by the first-order polymerization kinetics, the linear dependence of molecular weights of the polymers on the monomer conversions with the relatively narrow molecular weight distributions(Mw/Mn), and the successful chain extension experiments. The soluble polymers having tris(8-hydroxyquinoline)aluminum (Alq3) and bis(8-hydroxyquinoline) znic(II) (Znq2) side chains were obtained via complexation of the polymers with aluminium isopropoxide or zinc acetate in the presence of monomeric 8-hydroxyquinoline, which had strong fluorescent emission at 520 nm. The obtained polymers were characterized by GPC, NMR, UV-vis, and fluorescent spectra.

Fe-mediated ICAR ATRP of methyl methacrylate on photoinduced miniemulsion polymerization

e-Polymers ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Xue-Hui Zhan
Keyword(s):  
Methyl Methacrylate ◽  
Miniemulsion Polymerization ◽  
Gel Permeation Chromatography ◽  
Polymerization Time ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Chloride Hexahydrate ◽  
Weight Distributions ◽  
Gel Permeation ◽  
Ferric Chloride Hexahydrate

AbstractThe initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) were investigated in microemulsion under light irradiation with ethyl 2-bromoisbutyrate (EBiB) as an ATRP initiator, ferric chloride hexahydrate (FeCl3·6H2O) as a catalyst, N,N,N′,N′-tetramethyl-1,2-ethanediamine (TMEDA) as a ligand, and azobisisobutyronitrile (AIBN) as an initiator and reducing agent. The linear dependence of ln([M]0/[M]) on polymerization time was observed, indicating that the polymerization was living polymerization. Furthermore, the number-average molecular weights (Mn), gel permeation chromatography (GPC) and molecular weight distributions (MWD) of the PMMA obtained from GPC were controlled. The product was characterized by 1H nuclear magnetic resonance (NMR) and GPC. The living features were verified by chain-extended with MMA with the obtained PMMA as macroinitiator.

Reversible-deactivation radical polymerization of chloroprene and the synthesis of novel polychloroprene-based block copolymers by the RAFT approach

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55529-55538 ◽  
Author(s):  
Jia Hui ◽  
Zhijiao Dong ◽  
Yan Shi ◽  
Zhifeng Fu ◽  
Wantai Yang
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Radical Polymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Reversible Deactivation ◽  
Raft Agent ◽  
Reversible Deactivation Radical Polymerization

Novel, well-defined PCP-based block copolymers (PSt-b-PCP and PMMA-b-PCP) with controlled number averaged molecular weights and molecular weight distributions can be prepared, employing EPDTB and CPDB, respectively, as the initial RAFT agent.

High Temperature Initiator-Free RAFT Polymerization of Methyl Methacrylate in a Microwave Reactor

2009 ◽  
Vol 62 (3) ◽  
pp. 254 ◽  
Author(s):  
Renzo M. Paulus ◽  
C. Remzi Becer ◽  
Richard Hoogenboom ◽  
Ulrich S. Schubert
Keyword(s):  
High Temperature ◽  
Methyl Methacrylate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Linear Increase ◽  
Thermal Heating ◽  
Controlled Polymerization ◽  
Microwave Reactor ◽  
Reversible Addition ◽  
Raft Agent

The reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) was investigated under microwave irradiation. At first, a comparison was made between microwave and thermal heating for the RAFT polymerization of MMA with azobis(isobutyronitrile) (AIBN) as initiator and 2-cyano-2-butyldithiobenzoate (CBDB) as RAFT agent, revealing comparable polymerization kinetics indicating the absence of non-thermal microwave effects. Second, the CBDB-mediated RAFT polymerization of MMA was investigated at high temperatures (120°C, 150°C, and 180°C, respectively) in the absence of a radical initiator, showing a linear increase of the molar masses with conversion. The polydispersity indices remained below 1.5 up to 25% MMA conversion at 120°C and 150°C, indicating a controlled polymerization. This control over the polymerization was confirmed by the ability to control the molar masses by the concentration of RAFT agent.

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.

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