Numerical Simulation of Atom-Transfer Radical Polymerization of tert-butyl Methacrylate (original) (raw)
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Atom transfer radical polymerization of cyclohexyl methacrylate at a low temperature
Journal of Polymer Science Part A: Polymer Chemistry, 2005
The atom transfer radical polymerization of cyclohexyl methacrylate (CHMA) is reported. Controlled polymerizations were performed with the CuBr/ N,N,NЈ,NЉ,NЉ-pentamethyldiethylenetriamine catalytic system with ethyl 2-bromoisobutyrate as the initiator in bulk and different solvents (25 vol %) at 40°C. The polymerization of CHMA in bulk resulted in a controlled polymerization, although the concentration of active species was relatively elevated. The addition of a solvent was necessary to reduce the polymerization rate, which was dependent on the dipole moment. Well-controlled polymers were obtained in toluene, diphenyl ether, and benzonitrile solutions. Poly(cyclohexyl methacrylate) as a macroinitiator was used to synthesize the poly(cyclohexyl methacrylate)-b-poly(tert-butyl methacrylate) block copolymer, which allowed a demonstration of its living character. In addition, two difunctional initiators, 1,4-bis(bromoisobutyryloxy) benzene and 1,2-bis(bromoisobutyryloxy) ethane, were used to initiate the atom transfer radical polymerization of CHMA. The experimental molecular weights of the obtained polymers were very close to the theoretical ones. These, along with the relative narrow molecular weight distributions, indicated that the polymerization was living and controlled. For confirmation, two different poly(tert-butyl methacrylate)-b-poly(cyclohexyl methacrylate)-b-poly(tert-butyl methacrylate) triblock copolymers were also synthesized.
Pure and Applied Chemistry, 2023
Atom transfer radical polymerization (ATRP) is a versatile & famous technique for the synthesis of well defined molecular architectures. In ATRP, there is a dynamic equilibrium exists between active & dormant species. Therefore, ATRP progress through a sequence of activation & deactivation cycles, ending upon complete monomer consumption & termination reactions are minimized. This paper presents a systematic computational study on kinetics & thermodynamics associates in the ATRP of itaconimide monomers & methyl methacrylate (MMA). For this, the copolymerization system is modeled as a unimer, dimer & trimer of various itaconimides & MMA monomer. The density functional theory with B3LYP functional & 6–31 + G(d)/LanL2DZ basis sets is used in the prediction of geometries & energetics associated with the dissociation of terminal R–X bond present in the unimer, dimer & trimer. The relative equilibrium constant (K ATRP) for the ATRP activation/deactivation steps is calculated from the free...
Polymer, 2004
Atom transfer radical polymerization of lauryl methacrylate (LMA) was carried out in the presence of various ligands using ethyl-2bromoisobutyrate as initiator and CuBr as catalyst in toluene at 95 8C. The ligands used were 2,2 0-bipyridyl,4,4 0-dimethyl-2,2 0-bipyridyl, N,N,N 0 ,N 0 ,N 00-pentamethyldiethylenetriamine (PMDETA) and N-(n-propyl)-2-pyridylmethanimine (PPMI). Controlled polymerization was observed with PMDETA and PPMI ligands and poly(LMA)s with narrow molecular weight distribution (MWD) ðM w =M n # 1:2Þ were obtained. The first-order time-conversion plot showed the presence of termination in the presence of PMDETA. A linear first-order timeconversion plot with a small induction period (,10 min) was observed in the presence of PPMI ligand. Di-block copolymers of LMA and methylmethacrylate with controlled molecular weight and narrow MWDs were synthesized via sequential monomer addition.
Atom Transfer Radical Polymerization of Isobornyl Acrylate: A Kinetic Modeling Study
Macromolecules, 2010
A detailed kinetic modeling study of the atom transfer radical polymerization (ATRP) of isobornyl acrylate (iBoA) is presented. This study combines a detailed reaction scheme with a systematic approach to account for diffusional limitations. Calculated values for diffusion coefficients and the Williams-Landel-Ferry parameters for poly(iBoA) are based on rheological measurements. A good agreement with experimental data is obtained for the polymerization rate, average chain length, and polydispersity index in conditions ranging from 323 to 348 K for targeted chain lengths varying from 50 to 100 and initial activator/deactivator concentrations between 10-50/0-2.5 mol m-3. In these conditions, βC-scission reactions are insignificant and backbiting reactions result in a slight decrease of the polymerization rate and level of control at high conversions only. Termination is subject to diffusional limitations during the whole ATRP, while diffusional limitations on deactivation cannot be neglected at higher conversion. Diffusional limitations are shown to be codetermined by the evolution of the chain length distribution of both the end-chain and mid-chain macromolecular species.
Atom-Transfer Radical Polymerization of a Reactive Monomer: 3-(Trimethoxysilyl)propyl Methacrylate
Macromolecules, 2004
Atom-transfer radical polymerizations (ATRPs) of a reactive monomer, 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), mediated by CuBr/N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PM-DETA) in anisole have been studied using ethyl 2-bromoisobutyrate (2-EBiB) and poly(ethylene oxide) methyl ether 2-bromoisobutyrate (PEO-Br) as initiators. In general, the polymerizations of TMSPMA exhibited first-order kinetics, and molecular weights increased linearly with monomer conversion. Molecular weight distributions remained low throughout the polymerizations (M w/Mn ) 1.20-1.40). The overall rate of polymerization with PEO-Br as the initiator was enhanced compared to that with 2-EBiB as the initiator. A series of reactive diblock copolymers, poly(ethylene oxide)-b-poly[3-(trimethoxysilyl)propyl methacrylate] (PEO-b-PTMSPMA), were thus synthesized. By random copolymerization with methyl methacrylate (MMA), PEO-b-P(TMSPMA-r-MMA) copolymer was prepared at the same time. Organic/inorganic hybrid nanospheres were produced by the self-assembly of PEO-b-P(TMSPMA-r-MMA) in a selective solvent and further gelation of the trimethoxylsilyl groups within each individual sphere. Preparation of organic/inorganic nanocomposites was also explored preliminarily on the basis of the solgel process of PEO-b-PTMSPMA diblock copolymers and the tetraethyl orthosilicate.
Solvent effect on the atom transfer radical polymerization of allyl methacrylate
Journal of Polymer Science Part A: Polymer Chemistry, 2005
The controlled radical polymerization of allyl methacrylate by atom transfer radical polymerization was carried out in solution at 70 8C, with ethyl 2-bromoisobutyrate as the initiator and copper halide (CuX, where X is Cl or Br) with N,N,N 0 ,N@,N@-pentamethyldiethylenetriamine as the catalyst system. Kinetic analyses demonstrated that all the homopolymerization reactions showed a general behavior characterized by two clearly differentiated stages. Thus, in the early stage, the conversion increased continually with the time, independently of the solvent employed. In the second stage, a deceleration process took place, and a limit conversion was achieved, depending on the polarity and amount of the solvent used. The dependence of both the gel formation and limit conversion, as well as the molecular characteristics of poly(allyl methacrylate)s formed with different experimental parameters, such as the initial monomer concentration, the solvent employed, and the type of halide used as a catalyst, was also examined. The prepared polymers were characterized by size exclusion chromatography, Fourier transform infrared, and one-and two-dimensional nuclear magnetic resonance spectroscopy. Moreover, chain-growth experiments with butyl acrylate as the comonomer proved the living character of the poly(allyl methacrylate)s obtained, with these used as macroinitiators. V
Phase-Transfer-Agent-Aided Free Radical Polymerization of Methyl Methacrylate-A Kinetic Study
Journal of Macromolecular Science: Part A - Chemistry, 1991
Polymerization of butylacrylate under phase transfer conditions indifferent organic solvent/water mbctures is studied . The kinetic approach points to the Influence of the nature of the organic solvent as well as that of the volume ratio between aqueous and organic phase . The overall activation energy of the polymerization is calculated to be 70.3 kJ/mol and transfer constants CM and CI are found to be 3.98 x 10'5 and 2 .038 x 104, respectively.
Journal of Applied Polymer Science, 1997
In free radical polymerization diffusion-controlled processes take place simultaneously to the normal chemical reactions. Despite extensive efforts to model such processes a consistent model for the design of a polymerization reactor has not yet been established. In this article a semiempirical model describing the conversion, polymerization degree, and molecular weight distribution (MWD) for the free radical polymerization is developed for the entire course of the reaction. The model includes the change of termination, propagation, transfer, and initiation rate. By simultaneous parameter estimation from the conversion and degrees of polymerization data the model parameters have been determined for isothermal polymerizations of methyl methacrylate (MMA) and styrene (ST). The simulation results for the conversion, degrees of polymerization, and MWD are in good accordance with experimental data for suspension and bulk polymerization of MMA and ST up to very high conversions. The influence of diffusion on the propagation rate in case of polymerization of MMA is negligible compared to the influence of the cage effect on the radical efficiency; in case of ST polymerization both effects must be included in the kinetic model. The model presented is also tested for polymerizations conducted in the presence of solvent and / or chain transfer agents.