Radical Polymerization Of Methyl Acrylate Research Articles

Stereospecific Radical Polymerization of a Side-Chain Transformable Bulky Acrylamide Monomer and Subsequent Post-Polymerization Modification for Syntheses of Isotactic Polyacrylate and Polyacrylamide.

We report syntheses of isotactic polyacrylate and polyacrylamide via a stereospecific radical polymerization of a pendant-transformable monomer, acrylamide carrying isopropyl-substituted ureidosulfonamide (1), followed by post-polymerization modification (PPM). The study in the alcoholysis and aminolysis reactions of the model compound (2) for evaluation of the transformation ability of the electron-withdrawing pendant group on the repeating unit 1 revealed the following points: the pendant of the polymer became more reactive than that of monomer; the pendant was active enough for aminolysis reaction affording the amide compound quantitatively without additive/catalyst; the addition of a lithium triflate [Li(OTf)] and triethylamine (Et3 N) was effective as for promotion of the alcoholysis reaction. Poly(methyl acrylate) (PMA) was quantitatively obtained via the radical polymerization of 1 in the presence of Li(OTf) at 60 °C and the subsequent addition of methanol along with Et3 N. Thus-obtained PMA showed higher isotacticity [m=74 %] than that directly obtained via radical polymerization of methyl acrylate (MA) (m=51 %). The isotacticity was further increased as the temperature and monomer concentration were lower, and eventually m was increased up to 93 %. The aminolysis PPM after the iso-specific radical polymerization of 1 gave various isotactic polyacrylamides carrying different alkyl pendant groups, including poly(N-isopropylacrylamide) (PNIPAM).

Stereospecific Radical Polymerization of a Side‐Chain Transformable Bulky Acrylamide Monomer and Subsequent Post‐Polymerization Modification for Syntheses of Isotactic Polyacrylate and Polyacrylamide

AbstractWe report syntheses of isotactic polyacrylate and polyacrylamide via a stereospecific radical polymerization of a pendant‐transformable monomer, acrylamide carrying isopropyl‐substituted ureidosulfonamide (1), followed by post‐polymerization modification (PPM). The study in the alcoholysis and aminolysis reactions of the model compound (2) for evaluation of the transformation ability of the electron‐withdrawing pendant group on the repeating unit 1 revealed the following points: the pendant of the polymer became more reactive than that of monomer; the pendant was active enough for aminolysis reaction affording the amide compound quantitatively without additive/catalyst; the addition of a lithium triflate [Li(OTf)] and triethylamine (Et3N) was effective as for promotion of the alcoholysis reaction. Poly(methyl acrylate) (PMA) was quantitatively obtained via the radical polymerization of 1 in the presence of Li(OTf) at 60 °C and the subsequent addition of methanol along with Et3N. Thus‐obtained PMA showed higher isotacticity [m=74 %] than that directly obtained via radical polymerization of methyl acrylate (MA) (m=51 %). The isotacticity was further increased as the temperature and monomer concentration were lower, and eventually m was increased up to 93 %. The aminolysis PPM after the iso‐specific radical polymerization of 1 gave various isotactic polyacrylamides carrying different alkyl pendant groups, including poly(N‐isopropylacrylamide) (PNIPAM).

Effects of Alkyl Ester Chain Length on the Toughness of PolyAcrylate-Based Network Materials.

Polyacrylate-based network materials are widely used in various products owing to their facile synthesis via radical polymerization reactions. In this study, the effects of alkyl ester chains on the toughness of polyacrylate-based network materials were investigated. Polymer networks were fabricated via the radical polymerization of methyl acrylate (MA), ethyl acrylate (EA), and butyl acrylate (BA) in the presence of 1,4-butanediol diacrylate as a crosslinker. Differential scanning calorimetry and rheological measurements revealed that the toughness of MA-based networks drastically increased compared with that of EA- and BA-based networks; the fracture energy of the MA-based network was approximately 10 and 100 times greater than that of EA and BA, respectively. The high fracture energy was attributed to the glass transition temperature of the MA-based network (close to room temperature), resulting in large energy dissipation via viscosity. Our results set a new basis for expanding the applications of polyacrylate-based networks as functional materials.

Investigation of the effect of chelating nitrogenous bases on click reactions on poly[(methyl acrylate)‐co‐(5‐azido‐1‐pentene)

AbstractClick reactions on poly[(methyl acrylate)‐co‐(5‐azido‐1‐pentene)], synthesized by radical polymerization of methyl acrylate and 1‐bromo‐5‐pentene, and converted into the click‐ready azido form by nucleophilic substitution with sodium azide, were studied. Propargyl benzoate and propargyl acetate were clicked onto the polymeric substrate, with the latter known to be a poor click reactant. The impact of solvents (dimethyl formamide (DMF) and tetrahydrofuran (THF)), catalytic systems (CuSO4/Na ascorbate, [Cu(BPMEN)(ClO4)2]/Na ascorbate, bromotris(triphenylphosphine) copper(I) ([CuBr(PPh3)3])) and the addition of chelating nitrogenous bases (triethylamine (TEA), diisopropylethylamine, N,N,N′,N″,N″‐pentamethyldiethylenetriamine) on the degree of conversion was analyzed. Only reactions catalyzed with [CuBr(PPh3)3] led to high or complete conversions in both solvents. Reactions catalyzed with the pre‐catalyst complexes CuSO4⋅5H2O and [(CuBPMEN)(ClO4)2], which require the in situ reduction of Cu(II) to Cu(I) by sodium ascorbate, yielded incomplete conversions in both solvents. Adding chelating nitrogenous bases, with TEA being the most effective, yielded complete conversions for propargyl benzoate with all three catalytic systems in DMF. Adding TEA to reactions of propargyl acetate in DMF increased conversion by 17.9% for CuSO4⋅5H2O/Na ascorbate and 29.6% for [(CuBPMEN)(ClO4)2]/Na ascorbate. The addition of chelating bases was more effective in DMF than in THF, which was also the less suited solvent in reactions without chelating bases. The results show that click reactions with propargyl reagents that cannot increase the nucleophilicity of the vinylidene‐like β‐carbon through electron conjugation yield lower conversions. The effectiveness of catalytic systems that undergo in situ reductions can be enhanced by nitrogenous chelating bases that stabilize the Cu(I) stage. © 2023 Society of Industrial Chemistry.

Cobalt(II) and cobalt(III) complexes of tripodal tetradentate diamino-bis(phenolate) ligands: Synthesis, characterization, crystal structures and evaluation in radical polymerization processes

The synthesis and characterization of cobalt(II) (3, 4) and acetato cobalt(III) (5) complexes with two tripodal tetradentate diamino-bis(phenolate) ligands (L1 and L2) are reported. The solid-state structures of proligand H2L1 and complexes 4 and 5 were determined by X-ray crystallography. Complex 4 crystallizes as a dimer via the formation of a Co2O2 core. Complex 5 is monomeric with a six-coordinated cobalt(III) center bearing a chelating acetate ligand. In both structures, the diamino-bis(phenolate) ligand (L1 or L2) is acting as a tetradentate dianionic κ4-(O2,N2) chelating ligand. The diamagnetic nature of complex 5 allowed its characterization by multinuclear NMR spectroscopic techniques. Complex 5 is not a competent unimolecular initiator for the radical polymerization of methyl acrylate or methyl methacrylate. Its cobalt(II) analog (3) did not act as an efficient OMRP moderator for the radical polymerization of activated (styrene, tert-butyl acrylate) and non-activated (vinyl acetate) monomers.

Measurement and Modeling of Semi-Batch Solution Radical Copolymerization of N-tert-Butyl Acrylamide with Methyl Acrylate in Ethanol/Water.

The synthetic polymer industry is transitioning from the use of organic solvents to aqueous media in order to reduce environmental impact. However, with radical polymerization kinetics affected by hydrogen-bonding solvents, there is limited information regarding the use of water as a solvent for sparingly soluble monomers. Thus, in this paper, the radical polymerization of methyl acrylate (MA) and N-tert-butylacrylamide (t-BuAAm) is studied in water and ethanol (EtOH), as the copolymer product is of commercial interest. A series of semi-batch reactions are conducted under a range of operating conditions (i.e., reaction temperature, solvent-to-monomer ratio, and comonomer composition) to demonstrate that the copolymer can be successfully synthesized without significant drifts in product molar masses or composition. The experiments provide additional data to probe the influence of the solvent on the polymerization rate and copolymer properties, as the low monomer concentration maintained under starved-feed operation leads to a solvent-to-monomer ratio different from that in a batch system. A model that captures the influence of backbiting and solvent effects on rate, previously developed and tested against batch polymerizations, also provides an excellent description of semi-batch operation, validating the set of mechanisms and kinetic coefficients developed to represent the system.

Pd-Mediated Light-Controlled Living Radical Polymerization of Methyl Acrylate

Abstract The radical polymerization of methyl acrylate in the presence of a palladium dimer complex and ethyl iodoacetate as an initiator under photoirradiation conditions led to the formation of poly(methyl acrylate) having good Ð values. The polymerization could be controlled by switching the light on and off, exhibiting living characteristics. We propose that such α-Pd polyesters could function as dormant species, which would allow a pair of transient α-keto radicals and persistent Pd radicals to be generated upon photoirradiation.

ARGET ATRP of Methyl Acrylate and Methyl Methacrylate with Diazocine-Derived Initiators

Diazocine-functionalized initiators for atom transfer radical polymerization (ATRP) were synthesized and tested for their efficiency in controlled radical polymerizations of methyl acrylate and methacrylate under reaction conditions for activators regenerated by electron transfer (ARGET). The α-bromoisobutyl condensates of anilide and benzyloxycarbonate required high amounts of reducing agents and catalysts for the initiation. On the other hand, violet light irradiation during ATRP caused severe retardation or termination during initiation of the anilide compound, in contrast to the previously reported photoinduced initiation under otherwise very similar conditions. The final linear elastomers obtained from optimized polymerization kinetics responded to light irradiation of 405 and 525 nm wavelengths by Z/E photoisomerization of diazocine in both solution and in the solid state. The E → Z thermal relaxation rate was highly influenced by electronic effects on the diazocine ring, the solvent, and the polymer matrix in the solid state. Our polymers find potential use as photonic materials in ultraviolet light sensors and optical waveguides.

Kinetic Study on Ultraviolet Light-Induced Solution Atom Transfer Radical Polymerization of Methyl Acrylate Using TiO2

The kinetics of the ultraviolet light-induced solution atom transfer radical polymerization (ATRP) of methyl acrylate using titanium oxide (TiO2) was investigated through experiments and modeling b...

Synthesis and characterization of molybdenum (VI) complex immobilized on polymeric Schiff base‐coated magnetic nanoparticles as an efficient and retrievable nanocatalyst in olefin epoxidation reactions

In this study, a new polymeric functionalized magnetic nanocatalyst containing a molybdenum Schiff base complex was prepared using a few consecutive steps. Poly (methylacrylate)‐coated magnetic nanoparticles were synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups with hydrazine. Polymeric functionalization efficiently provides the advantage that more catalytic units can be grafted on the surface of magnetic nanoparticles. The functionalization process was continued with salicylaldehyde which introduced Schiff base groups on to the surface of the polymeric support. In the final step, the desired catalytic system was prepared via complexation of the Schiff base groups with MoO2(acac)2. The resulting nanoparticles were characterized by infrared spectroscopy, powder X‐ray diffraction, scanning and transmission electron microscopy, elemental analysis, inductively coupled plasma optical emission spectrometry, vibrating sample magnetometry and thermogravimetric analysis. This heterogenized catalytic system was also found to be highly active, sustainable and recyclable nanocatalyst in alkene epoxidation. Eventually, the attractive features of the synthesized catalyst such as simple work‐up, good stability, magnetic separation, high TOF and high surface area; make it appropriate for oxidation reactions.

Cobalt(II) phenoxy‐imine complexes in radical polymerization of vinyl acetate: The interplay of catalytic chain transfer and controlled/living radical polymerization

ABSTRACTA series of cobalt(II) phenoxy‐imine complexes (CoII(FI)2) have been synthesized to mediate the radical polymerization of vinyl acetate (VAc) and methyl acrylate (MA) to evaluate the influence of chelating atoms and configuration to the control of polymerization. The VAc polymerizations showed the properties of controlled/living radical polymerization (C/LRP) with complexes 1a and 3a, but the catalytic chain transfer (CCT) behaviors with complexes 2a, 1b, 2b, and 3b. The control of VAc polymerization mediated by complex 1a could be improved by decreasing the reaction temperature to approach the molecular weights that not only linearly increased with conversions but also matched the theoretical values and relatively narrow molecular weight distributions. The catalytic chain transfer polymerizations (CCTP) mediated by complexes 2a, 1b, 2b, and 3b were characterized by Mayo plots and the polymer chain end double bonds were observed by 1H NMR spectra. The tendency toward C/LRP or CCTP in VAc polymerization mediated by CoII(FI)2 could be determined by the ligand structure. Cobalt complex coordinated by the ligand with more steric hindered and less electron‐donating substituents favored the controlled/living radical polymerization. In contrast, the efficiency of CCT process could be enhanced by less steric hindered, more electron‐donating ligands. The controlled/living radical polymerization of MA, however, could not be achieved by the mediation of these cobalt(II) phenoxy‐imine complexes. Associated with the results of polymerization mediated by other cobalt complexes, this study implied that the configuration and spin state of cobalt complexes were more critical than the chelating atoms to the control behavior of radical polymerization. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 101–113

Polystyrene with Persistently Enhanced Fluorescence: Photo‐Induced Atom Transfer Radical Polymerization Using a Pyrene‐Based Initiator

AbstractThe pyrene‐based atom transfer radical polymerization (ATRP) initiator of 1‐pyrenemethyl 2‐bromoisobutyrate (PMBriB) was applied to the photo‐induced radical polymerization of methyl acrylate, methyl methacrylate, and styrene. During the polymerization, the fluorescence of the polymer solution caused by the chain end pyrene group was observed to be slightly enhanced in all cases, possibly due to the decline of the aggregation caused quenching (ACQ) effect. However, the fluorescence of polystyrene obtained from photo‐induced ATRP was significantly increased. Differential scanning calorimeter (DSC) measurements, NMR spectroscopy, and fluorescence measurements associated with a series of control studies demonstrated that the enhanced fluorescence was a persistent phenomenon in both solution and the solid state but the polystyrenes with and without enhanced fluorescence showed no observable difference in chemical bonding and molecular conformation. At this stage, the coexistence of pyrene, 2‐bromoisobutyrate group, styrene, and light was required for this novel phenomenon and the mechanism of this fluorescence enhancement is still being studied.

Photoinduced controlled radical polymerization of methyl acrylate and vinyl acetate by xanthate

A block copolymer of PMA-b-PVAc was successfully synthesized using photo-induced RAFT polymerization with a xanthate.

Kinetics of Single-Electron Transfer Living Radical Polymerization of Methyl Acrylate in the Presence of Anhydrous Ferric Chloride

Kinetics of Single-Electron Transfer Living Radical Polymerization of Methyl Acrylate in the Presence of Anhydrous Ferric Chloride

Synthesis of poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite for removal of lead contaminant from aqueous media

Poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite was synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the functionalization of the methyl ester groups with poly(amidoamine) dendrimer. The resulting poly(amidoamine)-graft-poly(methyl acrylate) magnetic nanocomposite was then characterized by infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, scanning electron microscope and X-ray diffraction analysis. Its application as an adsorbent for the removal of Pb(II) ions was studied. The removal capability of the adsorbent was investigated in different pH values, contact time (kinetics) and initial concentration of lead. Moreover, adsorption isotherms were investigated to describe the mechanistic feature of this nanocomposite for adsorption. Accordingly, its high adsorption capacity (310 mg/g) and efficient adsorption toward lead ions in aqueous solution were shown. To further study of the chemistry behind the adsorption process, a comprehensive density functional theory-based study was performed, and a relatively strong interaction between metal ions and adsorbent was observed based on the calculated adsorption free energies.

Ultrafast and efficient removal of cationic dyes using a magnetic nanocomposite based on functionalized cross-linked poly(methylacrylate)

In this study, a new magnetic nanocomposite was synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the functionalization of the methyl ester groups with ethylenediamine and sodium chloroacetate. The generated magnetic nanocomposite was characterized by FT-IR, TEM, SEM, TGA, VSM, XRD and elemental analysis. Its key role as an adsorbent for the removal of typical cationic dyes, methyl violet and malachite green was investigated in terms of pH, contact time and initial dye concentration. The resulted adsorbent displays excellent adsorption capacities for cationic dyes which are more effective than most of the adsorbents reported so far. Study of the kinetic and isotherm of adsorption indicated that dyes adsorption process is well-described by pseudo-second-order-kinetic and Langmuir isotherm models, respectively. Furthermore, to find an accurate correlation between the adsorption enthalpy (ΔH) and experimental maximum adsorption capacity (qm), calculation of the adsorption enthalpy of a series of cationic dyes onto MNC-EDDA adsorbent was investigated using density functional theory (DFT). Interestingly, an excellent agreement between experimental qm and calculated ΔH (kcal/mol) was found which is able to predict the maximum adsorption capacities onto the prepared adsorbent for the other cationic dyes.

Luminescent Nanocellulose Platform: From Controlled Graft Block Copolymerization to Biomarker Sensing.

A strategy is devised for the conversion of cellulose nanofibrils (CNF) into fluorescently labeled probes involving the synthesis of CNF-based macroinitiators that initiate radical polymerization of methyl acrylate and acrylic acid N-hydroxysuccinimide ester producing a graft block copolymer modified CNF. Finally, a luminescent probe (Lucifer yellow derivative) was labeled onto the modified CNF through an amidation reaction. The surface modification steps were verified with solid-state (13)C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy. Fluorescence correlation spectroscopy (FCS) confirmed the successful labeling of the CNF; the CNF have a hydrodynamic radius of about 700 nm with an average number of dye molecules per fibril of at least 6600. The modified CNF was also imaged with confocal laser scanning microscopy. Luminescent CNF proved to be viable biomarkers and allow for fluorescence-based optical detection of CNF uptake and distribution in organisms such as crustaceans. The luminescent CNF were exposed to live juvenile daphnids and microscopy analysis revealed the presence of the luminescent CNF all over D. magna's alimentary canal tissues without any toxicity effect leading to the death of the specimen.

A new functionalized magnetic nanocomposite of poly(methylacrylate) for the efficient removal of anionic dyes from aqueous media

A magnetic nano-adsorbent was synthesized via the radical polymerization of methyl acrylate on modified Fe3O4 MNPs, followed by amidation of the methyl ester groups using pentaethylenehexamine, to create active sites for adsorption of anionic dyes.

Atom transfer radical polymerization of methyl acrylate, methyl methacrylate and styrene in the presence of trolamine as a highly effective promoter

Abstract Transition metal-mediated atom transfer radical polymerization (ATRP) is a “living”/controlled radical polymerization. Recently, there has been widely increasing interest in reducing the high costs of catalyst separation and post-polymerization purification in ATRP. In this work, trolamine was found to significantly enhance the catalytical performance of CuBr/ N , N , N ′, N ′-tetrakis(2-pyridylmethyl) ethylenediamine (CuBr/TPEN) and CuBr/tris[2-(dimethylamino) ethylamine] (CuBr/Me 6 TREN). With the addition of 25-fold molar amount of trolamine relative to CuBr, the catalyst loadings of CuBr/TPEN and CuBr/Me 6 TREN were dramatically reduced from a catalyst-to-initiator ratio of 1 to 0.01 and 0.05, respectively. The polymerizations of methyl acrylate, methyl methacrylate and styrene still showed first-order kinetics in the presence of trolamine and produced poly(methyl acrylate), poly(methyl methacrylate) and polystyrene with molecular weights close to theoretical values and low polydispersities. These results indicate that trolamine is a highly effective and versatile promoter for ATRP and is promising for potential industrial application.

Critically evaluated rate coefficients in radical polymerization – 7. Secondary-radical propagation rate coefficients for methyl acrylate in the bulk

Benchmark propagation rate coefficient (kp) data for the radical polymerization of methyl acrylate are provided.