Showing papers on "Methyl acrylate published in 1998"
TL;DR: In this article, the effects of reaction conditions and catalyst structure on the copolymerization reaction were rationalized, and the effect of the acrylate comonomer at the ends of branches as −CH2CH2C(O)OMe groups was analyzed.
Abstract: Mechanistic aspects of palladium-catalyzed insertion copolymerizations of ethylene and α-olefins with methyl acrylate to give high molar mass polymers are described. Complexes [(N∧N)Pd(CH2)3C(O)OMe]BAr‘4 (2) or [(N∧N)Pd(CH3)(L)]BAr‘4 (1: L = OEt2; 3: L ⋮ NCMe; 4: L ⋮ NCAr‘) (N∧N ≡ ArNC(R)−C(R)NAr, e.g., Ar ⋮ 2,6-C6H3(i-Pr)2, R ⋮ H (a), Me (b); Ar‘ ⋮ 3,5-C6H3(CF3)2) with bulky substituted α-diimine ligands were used as catalyst precursors. The copolymers are highly branched, the acrylate comonomer being incorporated predominantly at the ends of branches as −CH2CH2C(O)OMe groups. The effects of reaction conditions and catalyst structure on the copolymerization reaction are rationalized. Low-temperature NMR studies show that migratory insertion in the η2-methyl acrylate (MA) complex [(N∧N)PdMe{H2CCHC(O)OMe}]+ (5) occurs to give initially the 2,1-insertion product [(N∧N)PdCH(CH2CH3)C(O)OMe]+ (6), which rearranges stepwise to yield 2 as the final product upon warming to −20 °C. Activation parameters (ΔH⧧ = ...
857 citations
TL;DR: In this article, the synthesis of di-and triblock copolymers, involving methyl methacrylate (MMA), butyl acrylate, and methyl acrylated, using copper-based atom transfer radical polymerization (ATRP) is reported.
Abstract: The synthesis of di- and triblock copolymers, involving methyl methacrylate (MMA), butyl acrylate, and methyl acrylate, using copper-based atom transfer radical polymerization (ATRP) is reported. It was found that poly(MMA) macroinitiator is able to initiate the ATRP of acrylic monomers. However, for polyacrylates to effectively initiate the ATRP of MMA, the end group should be a bromine atom and the catalyst CuCl; that is, halogen exchange should take place. ABA-type triblock copolymers, where B = poly(butyl acrylate) and A = poly(methyl methacrylate), were synthesized by growing the center block first using a difunctional initiator and then adding MMA to the ends.
322 citations
TL;DR: In this paper, the NiBr2(Pn-Bu3)2-based initiator was shown to achieve a high temperature (120 °C; ∼90% conversion in 2.5 h) or at its high concentration, because it is more thermally stable and more soluble in organic solvents.
Abstract: Nickel(II) bromide bis(tri-n-butylphosphine) [NiBr2(Pn-Bu3)2] induced living radical polymerization of methyl methacrylate (MMA), methyl acrylate (MA), and n-butyl acrylate (BA) in conjunction with an organic bromide initiator [R−Br: CCl3Br, (CH3)2CBrCO2C2H5, and (CH3)2CBrCOPh] in the presence of Al(Oi-Pr)3 additive. In addition, the initiating system with an MMA “dimer” model of the bromine-capped dormant polymer [(CH3)2C(CO2CH3)CH2(CH3)CBrCO2CH3] gave living polymers with very narrow MWDs (Mw/Mn ∼ 1.1). Similar living polymerizations were possible in the absence of Al(Oi-Pr)3. NiBr2(Pn-Bu3)2 led to faster living polymerizations at a high temperature (120 °C; ∼90% conversion in 2.5 h) or at its high concentration, because it is more thermally stable and more soluble in organic solvents than NiBr2(PPh3)2. This feature permitted the synthesis of living PMMA of higher molecular weight (Mn ∼ 4 × 105) with narrow molecular weight distributions (Mw/Mn = 1.2−1.4). The NiBr2(Pn-Bu3)2-based system was also ...
169 citations
TL;DR: In this paper, the authors investigated the grafting of polyamidoamine dendrimer onto the silica surface by adding methyl acrylate to surface amino groups and amidation of the resulting esters with ethylenediamine.
Abstract: To modify ultrafine silica surface, the grafting of polyamidoamine dendrimer, a new class of topological macromolecules, onto the silica surface was investigated. Introduction of amino groups as an initiator site on the silica surface was achieved by the treatment of the silica with γ-aminopropyltriethoxysilane. Polyamidoamine dendrimer was propagated from silica surface by repeating two processes: (1) Michael addition of methyl acrylate to surface amino groups, and (2) amidation of the resulting esters with ethylenediamine. The amino group content of the resulting silica increased from 0.40 mmol/g to 8.30 mmol/g after 10th generation. In addition, the percentage of grafting increased with increasing generation and reached to 575.7% after 10th generation. However, these values were considerably smaller than the theoretical values. This indicates that the propagation of dendrimer grafting from silica surface was not achieved theoretically and ‘dendrimer-like’ highly branched polymer was grafted onto the surface, because of steric hindrance of grafted dendrimer. The effects of amino group content as an initiator site and reaction conditions on the grafting of the polymer onto silica surface were also investigated. Dendrimer-like highly branched polymer grafted ultrafine silicas gave a stable dispersion in a good solvent for the polyamidoamine dendrimer.
159 citations
TL;DR: In this article, the thermal behavior and miscibility of amorphous and crystalline polylactides (PDLA and PLLA) with poly(methyl methacrylate) (PMMA) and poly (methyl acrylate), along the entire composition interval were studied by differential scanning calorimetry (d.s.c.).
153 citations
TL;DR: In this article, the propagation rate coefficients for homopolymerization of methyl acrylate and dodecyl methacrylate were determined by the pulsed laser polymerization (PLP)/size-exclusion chromatography (SEC) technique at pressures between 100 and 2000 bar.
Abstract: Propagation rate coefficients (k p ) for the homopolymerization of methyl acrylate (MA) and dodecyl acrylate (DA) were determined by the pulsed laser polymerization (PLP)/size-exclusion chromatography (SEC) technique at pressures between 100 and 2000 bar. The activation volumes for the propagation step, ΔV#(k p ), of MA and DA are identical within experimental accuracy, but are clearly different from the previously reported ΔV#(k p ) of methyl and dodecyl methacrylate. For both the alkyl acrylates and methacrylates a pronounced family-type behaviour of k p is seen, with k p being slightly enhanced toward larger ester size.
150 citations
TL;DR: In this paper, a modified microemulsion polymerization process was used to obtain high polymer: surfactant weight ratios (7 : 1 or greater), relatively concentrated (10 − 30 wt.-%) latexes and small (10 -20 nm) particle diameters.
Abstract: Polymer nanoparticles were prepared from monomers such as styrene (St), butyl methacrylate (BMA), butyl acrylate (BA), methyl methacrylate (MMA), and methyl acrylate (MA) using a modified microemulsion polymerization process. With this process high polymer: surfactant weight ratios (7 : 1 or greater), relatively concentrated (10–30 wt.-%) latexes and small (10–20 nm) particle diameters were attained. Nucleation mechanisms were investigated through observations of the particle size change during the polymerization.
98 citations
TL;DR: In this article, a new methodology for the synthesis of (E)-3-benzylidenechroman-4-ones using methyl 3-aryl-3-hydroxy-2-methylenepropanoates, derived from methyl acrylate, is described.
95 citations
TL;DR: In this article, 2-Acryloyloxyethyl phosphorylcholine (APC) was synthesized and copolymerised with methyl methacrylate (MMA) and methyl acrylate(MA) to lead to a PC functional terpolymer.
88 citations
TL;DR: The study of critical micelle concentrations and micellar sizes indicated that the formation of micelles is primarily determined by the hydrophobic/hydrophilic properties of these copolymers.
80 citations
TL;DR: In this article, the thermal stability and degradation behavior of poly(4-vinylpyridine) (PVP) homopolymer and copolymers of 4vinyl pyridine and methyl acrylate (VP-MA) were investigated.
TL;DR: Chiral ligands with achiral backbones such as ethano- or ferroceno-bridges linking two phosphonites derived from chiral diols such as binaphthol (BINOL) have been prepared; the corresponding Rh complexes are excellent catalysts in the hydrogenation of prochiral olefins such as itaconic acid dimethyl ester or 2-acetamido methyl acrylate, the ee values being 90−99.5% as mentioned in this paper.
TL;DR: In this paper, a co-cyclization with electron deficient alkenes (methyl acrylate, methyl trans-crotonate, methyl cinnamate and diethyl fumarate) was shown to be regioselective with respect to the biclopropylidene.
TL;DR: The first members of a homologous series of long-chain, multiply unsaturated esters were obtained upon selective ring-opening metathesis of cyclopentene with methyl acrylate.
Abstract: The first members of a homologous series of long-chain, multiply unsaturated esters were obtained upon selective ring-opening metathesis of cyclopentene with methyl acrylate [Eq. (a)]. The catalysts are cationic carbynehydridoruthenium complexes (e.g. L=OEt2), which were prepared for the first time by protonation of hydridovinylideneruthenium compounds in the presence of L.
TL;DR: In this article, the effect of molecular weight on the segmental dynamics of bulk and adsorbed poly(methyl acrylate)-d3 (PMA-d3) was studied.
Abstract: Deuterium solid-state quadrupole-echo NMR was used to study the effect of molecular weight on the segmental dynamics of bulk and adsorbed poly(methyl acrylate)-d3 (PMA-d3). It was found that the bulk PMA-d3 with lower molecular weight was more mobile and more heterogeneous in motion than the high molecular weight species. Surface samples with coverages up to saturation coverage in toluene, adsorption maximum in toluene (Am), were prepared by adsorption of PMA-d3 with two different molecular weights onto silica from different solvent systems. After drying, the spectra were collected from the surface species at the solid−air interface. For the adsorbed polymers, the low molecular weight PMA-d3 segments on silica were more rigid than those of the high molecular weight PMA-d3. For both molecular weights, the surface polymers exhibited a wider range of mobilities than the bulk polymers.
TL;DR: Results indicate that control in ATRP does not originate in interactions of growing radicals with copper complexes but in the reversible halogen atom transfer.
Abstract: The effects of copper(I) and copper(II) metal centers on the atom transfer radical polymerization (ATRP) of styrene and methyl acrylate were investigated. The free-radical polymerizations were initiated by AIBN in the presence of copper(I) and copper(II) complexes. For methyl acrylate, the rate of the polymerization was reduced in the presence of CuIBr/dNbpy and CuIOTf/dTbpy but was unaffected by the presence of CuII(OTf)2/dTbpy. For styrene, under conditions which yield relatively low molecular weight polymer (16 000), no effect was observed in the presence of CuII(OTf)2/dNbpy; however, under conditions which yield high molecular weight polystyrene (50 000-100 000), the polymerization was limited in the molecular weight attainable and stopped at partial conversion. No effect was observed for the free-radical polymerization of styrene in the presence of copper(I) complexes. These results indicate that control in ATRP does not originate in interactions of growing radicals with copper complexes but in the reversible halogen atom transfer.
TL;DR: The aziridine toluene-p-sulfonamide as discussed by the authors was shown to give β-silylethyl sulfonamides, which is an anomalous result.
Abstract: The toluene-p-sulfonamides of secondary amines and indoles are cleaved by treatment with phenyldimethylsilyllithium to give the secondary amines. Aziridine toluene-p-sulfonamides, however, are opened by attack of the silyllithium reagent on carbon to give β-silylethyl sulfonamides. The aziridine toluene-p-sulfonamide 22 derived from norbornene is different in giving the 2-[dimethyl(phenyl)silyl]-4-methylbenzenesulfonamide 23 of exo-norbornylamine. The aziridine toluene-p-sulfonamides 26, 28 and 30, derived from methyl cinnamate, methyl acrylate and cinnamyl acetate, are also anomalous, giving 3-[N-(p-tolylsulfonyl)amino]-3-phenylpropionic acid 27, {3-[N-(p-tolylsulfonyl)amino]propionyl}dimethyl(phenyl)silane 29 and trans-cinnamyl alcohol 31, respectively, each derived by opening of the aziridine ring followed by loss of the silyl group.
TL;DR: In this paper, the ratio of endo-to exo-products in the Diels-Alder reaction between cyclopentadiene and methyl acrylate in supercritical carbon dioxide, plotted vs. the density of the medium, was found to go through a maximum at a density higher than the critical density.
Abstract: The ratio of endo- to exo-products in the Diels–Alder reaction between cyclopentadiene and methyl acrylate in supercritical carbon dioxide, plotted vs. the density of the medium, was found to go through a maximum at a density higher than the critical density. The effect can be explained in terms of the adjustment of the position of the nearest-neighbour solvent molecules with respect to the transition state. A theoretical discussion is given, which justifies this process being described as ‘potential tuning’.
TL;DR: Methyl acrylate, methacrylic acid, and acrylic acid have been graft copolymerized onto styrene-butadiene block copolymers as mentioned in this paper, and all three monomers react through the macroradical interacting with the double bond of butadiene.
TL;DR: In this paper, crown ethers anellated to glucose units were used to catalyse the enantioselective Michael addition of methyl phenylacetate to methyl acrylate in high chemical yields in up to 84% enantiomeric excess.
TL;DR: In this paper, Ni-clusters stabilized by tetraoctyl- or tetradodecylammonium bromide are readily available by electrochemical fabrication, the average size of the particles being 2.5 nm. Colloidal solutions of such clusters effectively catalyze the cycloaddition of methylenecyclopropane to methyl acrylate.
TL;DR: In this paper, the reaction of chromium tricarbonyl complexed aryl aldehydes and ketones with samarium(II) iodide and methyl acrylate results in formation of cyclic lactones as single diastereomers.
TL;DR: The present article describes the preparation of films of various thickness and microspheres from new resorbable graft copolymers of polyacrylic, MMA, or polyvinylic chains and poly(l-lactic acid) (PLLA) side blocks charged with 15-20% of ibuprofen (IBU) (a non-steroidic antiinflammatory agent).
TL;DR: In this article, the effect of the methyl acrylate content of PAN copolymers on the cyclization mechanism and fine structural changes in polymer chains under various heat treatment conditions was examined using both physical and chemical techniques.
Abstract: The acrylate comonomer in polyacrylonitrile (PAN) precursor markedly influences the microstructure of PAN fiber and its resulting carbon fiber. In this study, the change occurring during the heat treatment of PAN copolymers (acrylonitrile-co-methyl acrylate) in the presence of air up to 260°C has been examined using both physical and chemical techniques. Considering the effect of the methyl acrylate content of PAN copolymers on the cyclization mechanism and fine structural changes in polymer chains under various heat treatment conditions, the composition of acrylonitrile and methyl acrylate = 98 : 2 to 97 : 3 mol % was suitable for the precursor preparation because the cyclization mechanism and fine structural changes in the boundary of this composition of copolymers were significantly different. With increasing MA content, the exothermic onset and peak in the thermogram was found to shift toward higher temperatures, and the aromaticity index decreased. This evidence indicates that MA was believed not to activate at all but to interfere with the cyclization. Additionally, by means of 13C nuclear magnetic resonance (13C-NMR) analysis, the tacticities of copolymers were nearly same, regardless of the copolymer composition, and the cyclization occurred nonstereospecifically during the initial heat treatment at 240°C for 1 h. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2205–2213, 1998
TL;DR: In this article, the diastereoselectivity in the asymmetric Michael reaction using chiral imines/secondary enamines under neutral conditions has been investigated with the help of AM1 calculations.
Abstract: The diastereoselectivity in the asymmetric Michael reaction using chiral imines/secondary enamines under neutral conditions has been investigated with the help of AM1 calculations. The energetic differences between the two competing transition states involving enamino ketones 7d , 7g and methyl acrylate are in good agreement with the stereoselectivities observed with the corresponding chiral imines, derived from 1-phenylethylamine (de 95%) and from 1-cyclohexylethylamine (de 45%). The calculated transition structures indicate that steric factors govern the π-facial discrimination.
TL;DR: Zinc ion-exchanged mesoporous aluminosilicate has been designed specifically to accelerate the Diels-Alder reaction between cyclopentadiene and poor dienophiles such as methyl acrylate and methyl methacrylate as mentioned in this paper.
Abstract: Zinc ion-exchanged mesoporous aluminosilicate has been designed specifically to accelerate the Diels-Alder reaction between cyclopentadiene and poor dienophiles such as methyl acrylate and methyl methacrylate. Catalysis on this aluminosilicate is more effective than on a K 10-based solid acid catalyst.
TL;DR: In this paper, it was detected through grafting onto silica that atactic poly(methyl acrylate) showed unpredictably specific retention selectivity against polycyclic compounds with π-electrons as if molecular shape recognition was performed.
Abstract: It was detected through grafting onto silica that atactic poly(methyl acrylate) showed unpredictably specific retention selectivity against polycyclic compounds with π-electrons as if molecular-shape recognition was performed. This specificity was discussed with retention behaviors in several other polymer-grafted silicas and by proposing a parameter f to evaluate the contribution of π-π interaction.
TL;DR: In this article, the authors analyzed the head-to-head defect structure of poly(vinylidene fluoride) (PVF2) and its blends and showed that the molecular mechanism of crystallization of PVF2 is very much dependent on the H-H defect structure in the chains.
TL;DR: In this article, solvent-free and liquid-liquid PTC conditions have been used for the Michael addition of several enolates to methyl vinyl ketone, chalcone and methyl acrylate.
TL;DR: In this paper, free radical polymerization of acryloyl chloride (AC) was conducted in the following solvents: dichloroethane, ethyl acetate, tetrahydrofuran, dichloromethane, dioxane, and cyclohexane.
Abstract: Free radical polymerization of acryloyl chloride (AC) was conducted in the following solvents: dichloroethane, ethyl acetate, tetrahydrofuran, dichloromethane, dioxane, and cyclohexane. However, poly(acryloyl chloride) with high molecular weights could be obtained only in solvent cyclohexane. The molecular weights of poly(acryloyl chloride) could be measured through analogous poly(methyl acrylate). The reactivity ratios of AC (M1) with styrene (St) or vinyl acetate (VA) obtained by the extended Kelen–Tudos method at 42°C with dicyclohexylperoxydicarbonate as initiator in dioxane were found to be AC-St (r1 = 0.09 ± 0.1, r2 = 0.40 ± 0.1) and AC-VA (r1= 0.84 ± 0.1, r2 = 0.03 ± 0.1), respectively. The Q and e values of AC calculated from obtained r1 and r2 were 0.58 and 1.02. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 665–670, 1998