Radical Copolymerization Of Methyl Acrylate Research Articles

Mn2(CO)10-Induced Controlled/Living Radical Copolymerization of Methyl Acrylate and 1-Hexene in Fluoroalcohol: High α-Olefin Content Copolymers with Controlled Molecular Weights

A highly active manganese complex [Mn2(CO)10] efficiently induced the controlled/living radical copolymerizations of a conjugated polar vinyl monomer, methyl acrylate (MA), and an unconjugated nonpolar olefin, 1-hexene (1-Hex), in the presence of ethyl 2-iodoisobutyrate (EMA−I) as an initiator under weak visible light at 40 °C to give the copolymers with controlled molecular weights. The further use of protic fluoroalcohols as solvents enhanced the copolymerization without losing the molecular weight control to result in a high 1-Hex content up to 50 mol %, for which the predominant alternating sequences were confirmed by the 13C NMR analysis of the copolymers. The kinetic analysis of the copolymerizations revealed an increase in the reactivity of the MA-radical to the 1-Hex monomer in the fluoroalcohol [1/rMA = 0.49 in (CF3)2CHOH vs 0.081 in toluene], which can be attributed to the 1:1 hydrogen-bonding interaction between the MA unit and the fluoroalcohol as suggested by the 13C NMR analysis of the MA−fluoroalcohol mixtures [Kassn = 2.21 L/mol for (CF3)2CHOH]. Thus, a combination of a highly active Mn2(CO)10 catalyst and a protic fluoroalcohol solvent is effective for the alternating controlled/living radical copolymerization of acrylic monomers and α-olefins.

Kinetic Study of Atom Transfer Radical Copolymerization of Methyl Acrylate and Methyl Methacrylate Initiated with Poly(vinyl acetate) Macroinitiator

Atom transfer radical bulk copolymerization of MA and MMA was performed in the presence of CuCl/PMDETA as catalyst system and trichloromethyl‐terminated poly(vinyl acetate) macroinitiator at 80°C. The overall monomer conversion was followed gravimetrically and chemical composition of the copolymer was determined by 1H‐NMR spectrometry. The results have been used to calculate monomer reactivity ratios by linear and nonlinear methods. Reactivity ratios calculated were in the range of 0.3766–0.4988 and 1.8832–2.0963 for MA and MMA, respectively. These values were in good agreement with the values reported for a similar system in the free radical copolymerization. It was observed that the copolymerization system tends to produce a random copolymer with longer sequences of MMA than MA in the initial stage of polymerization before any significant decrease of the concentration of MMA in the monomer mixture. Copolymer microstructures in this study indicated that radical stabilization capability of MMA compared to MA is higher. The accuracy of the reactivity ratios were confirmed by 95% joint confidence limits. It was found that considering the effect of conversion in these methods makes the calculation result more accurate. The theoretical composition drifts in the comonomer mixture and copolymer as a function of the overall monomer conversion are also reported.

Facile synthesis of two-photon absorbing polymers through radical copolymerization

A two-photon absorbing polymer has been prepared through radical copolymerization of methyl acrylate and a synthesized monomer containing a two-photon absorbing chromophore (E,E,E)-1,3,5-tristyrylbenzene (1), under conven- tional radical polymerization conditions. The synthesized polymer was characterized by nuclear magnetic resonance (NMR), infra-red spectroscopy (IR) and gel permeation chromatography (GPC). The linear and nonlinear optical properties were studied by measurement of UV-Vis absorption, fluorescent emission and two-photon cross-section. This synthetic strategy provided a facile approach for synthesis of photonic materials with adjustable chromophore concentration and high molecular weights.

Effect of excess halide on the palladium‐catalyzed insertion‐triggered radical copolymerization of methyl acrylate and 1‐hexene

Abstract[Pd2(μ‐Cl)2(C6F5)2(tht)2] (1) is a very efficient initiator of the radical polymerization of methyl acrylate, but it is not active in the polymerization of methyl methacrylate or in the copolymerization with 1‐hexene. The addition of an excess of NBu4Cl to solutions of [Pd2(μ‐Cl)2(C6F5)2(tht)2] (1) provides an initiator system that copolymerizes methyl acrylate and 1‐hexene by an insertion‐triggered radical mechanism. Random copolymers are obtained with 11% incorporation of 1‐hexene in moderate yields (about 35%). Studies of the decomposition products obtained after the first insertion of methyl acrylate in the PdC6F5 bond of 1 show that the addition of excess halide in the presence of monomer favors the homolytic cleavage of the PdC bond, and the generation of the radicals that are active species in the polymerization, versus alternative evolution pathways. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5682–5691, 2006

Electron Spin Resonance Study of Monomeric, Dimeric, and Polymeric Acrylate Radicals Prepared Using the Atom Transfer Radical Polymerization TechniqueDirect Detection of Penultimate-Unit Effects

Model radicals generated through the reaction of organotin compounds with radical precursors prepared by atom transfer radical addition (ATRA) or atom transfer radical polymerization (ATRP) were studied by electron spin resonance (ESR). Dimers of various (meth)acrylate units, methyl acrylate (MA), tert-butyl acrylate (tBA), and methyl methacrylate (MMA), MA-MA-Br, MA-tBA-Br, tBA-tBA-Br, MMA-tBA-Br, and MA-MMA-Br, were prepared by ATRA. These dimers provided radicals mimicking the active species in a radical copolymerization of MA, MMA, and tBA. Well-resolved ESR spectra of the dimeric radicals confirm electronic and steric effects of the penultimate unit on the propagating radical. Hyperfine splitting constants observed for monomeric, dimeric, oligomeric, and polymeric tert-butyl acrylate radicals depend on the polymer chain length. The variation of ESR spectra with the chain length and penultimate unit was compared with the rate constants of activation in an ATRP using a CuBr/bpy catalyst system.

On the kinetic model for the radical copolymerization of methyl acrylate and sulfur dioxide

On the kinetic model for the radical copolymerization of methyl acrylate and sulfur dioxide

Studies on the radical copolymerization of methylacrylate with styrene using ZnCl2 as an accelerator

The kinetic investigation of the radical copolymerization of methylacrylate (MA) with styrene (Sty) using zinc chloride (ZnCl2) as an accelerator was carried out at 60 ± 0.1 °C for 120 min. The rate of polymerization was proportional to the concentrations of ZnCl2 and monomers. The energies of activation in the presence and absence of the complex are 34 and 89 kJ mol−1, respectively.

Studies on imidazolium‐p‐chlorophenacylide initiated copolymerization of methyl acrylate with styrene

AbstractThe radical copolymerization of methyl acrylate and styrene initiated by imidazolium‐p‐chlorophenacylide has been studied. The reaction orders with respect to initiator and monomer concentrations, and the energy of activation were determined. By NMR spectroscopy is shown that alternating copolymers resulted.

On the copolymerization model and microstructure of methyl acrylate ‐ styrene radical copolymer. Influence of ZnCl2

AbstractBulk radical copolymerization of methyl acrylate (MeA, M1) with styrene (St, M2) in presence and absence of ZnCl2 as complexing agent was studied. 1H‐NMR spectra were used to establish copolymer composition and sequence distribution. The methoxy group signal was observed to be split due to pentads, but the analysis of sequence distribution is possible only at triad level. Both composition and sequence distribution data confirmed that bulk radical copolymerization respects quite well the terminal addition model; the values of r1 = 0.14 ± 0.02 (from composition data) and r1 = 0.25 ± 0.03 (from sequence distribution data) and r2 = 0.83 ± 0.10 (from composition data) were found. The presence of ZnCl2 increases the probability of alternating addition, e.g., for [ZnCl2]/[MeA] = 0.2, r1 = 0.03 ± 0.02 and r2 = 0.17 ± 0.03. The radical copolymer obtained in bulk in the absence of ZnCl2 presents a coisotactic configuration with σ = 0.75 ± 0.03, but the presence of the complexing agent reduces the probability of coisotactic addition, e.g., for [ZnCl2]/[MeA] = 0.2, σ = 0.52 ± 0.03.

Free Radical Copolymerizations of N-Arylmaleimides

Abstract The free radical copolymerization of methyl acrylate (MA) with N-phenylmaleimide (NPMI) and N-p-tolylmaleimide (NPTMI) at 75° C in cyclohexanone solution initiated by AZBN was studied. The copolymer composition has been calculated from the nitrogen content estimated by the micro-Kjeldahl's method and by NMR spectral studies. The reactivity ratios have been calculated by Mayo and Lewis, Fineman and Ross, Glen and Tüdös, and Joshi and Joshi methods. Q and e values of NPMI and NPTMI were also calculated. Since the reactivity ratios are the measure of distribution of monomer units in a copolymer chain, the values obtained are compared and discussed.

アクリル酸メチルと塩化ビニリデンのラジカル共重合における五塩化アンチモンの添加効果

アクリル酸メチルと塩化ビニリデンのラジカル共重合における五塩化アンチモンの添加効果