AGET ATRP Of Methyl Methacrylate Research Articles

Iron-Mediated AGET ATRP of Methyl Methacrylate in Green Polar Ethyl Lactate Solvent without any External Ligand

Iron-Mediated AGET ATRP of Methyl Methacrylate in Green Polar Ethyl Lactate Solvent without any External Ligand

Investigating the Effect of Silica Aerogel Nanoparticles on the Kinetics of AGET ATRP of Methyl Methacrylate

Abstract Hexamethyldisilazane-modified silica aerogel nanoparticles were used for in situ polymerization of methyl methacrylate by activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) to synthesize tailor-made PMMA nanocomposites. Appropriate dispersion of silica aerogel nanoparticles in the monomer solution and improvement in interfacial interaction between the PMMA matrix and nanoparticles are two main reasons for application of HMDS-modified silica aerogel nanoparticles. Nitrogen adsorption/desorption isotherm was employed to examine surface area and structural characteristics of the HMDS-modified silica aerogel nanoparticles. Evaluation of size distribution and morphological studies were also performed by SEM and TEM. Conversion and molecular weight determinations were carried out using GC and SEC, respectively. Addition of 3 wt% HMDS-modified silica aerogel nanoparticles leads to decrement of conversion from 85 to 64%. Molecular weight of PMMA chains also decreases from 13,912 to 10,810 g⋅mol−1 by addition of only 3 wt% HMDS-modified silica aerogel nanoparticles; however, polydispersity index values increases from 1.18 to 1.51. Linear increase of ln(M0/M) with time for all the samples shows that polymerization proceeds in a living manner. In addition, suitable agreement between theoretical and experimental molecular weight in combination with low PDI values can appropriately demonstrate the living nature of the polymerization. TGA results indicate that by increasing HMDS-modified silica aerogel nanoparticles content, slight improvements in thermal stability of the nanocomposites were obtained. DSC results show a decrease in Tg from 86.9 to 80.1°C by addition of 3 wt% HMDS-modified silica aerogel nanoparticles.

Active, effective, and “green” iron(iii)/polar solvent catalysts for AGET ATRP of methyl methacrylate with various morphologies of elemental silver as a reducing agent

This article reports the AGET ATRP of MMA, with various morphologies of elemental silver as a reducing agent and an iron(iii)/polar solvent catalyst.

Iron-catalyzed AGET ATRP of methyl methacrylate using an alcohol as a reducing agent in a polar solvent.

The alcohols, methanol, ethanol, ethylene glycol (EG), and glycerol, were used as reducing agents for iron(III)-catalyzed activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate in polar solvents (N,N-dimethylformamide, N-methylpyrrolidone, or acetonitrile). The effects of the iron catalyst, initiator and alcohol on polymerization were investigated, and most of the systems showed the typical features of controlled radical polymerization. In studies of the ATRP behavior, polymerizations were well controlled with a linear increase in the molecular weight (Mn) versus conversion in agreement with the theoretical one, and low molecular weight distributions (Mw/Mn) were observed throughout the reactions. To gain a deeper understanding of the iron(III)/polar solvent-mediated ATRP, the polymerizations of various monomers (methyl acrylate, methyl methacrylate, n-butyl acrylate, and n-butyl methacrylate) were also investigated.

Bulk AGET ATRP of methyl methacrylate using iron(iii) acetylacetonate as a catalyst

In this work, polymerization of methyl methacrylate (MMA) was successfully conducted by atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) at 90 °C, using iron(III) acetylacetonate (Fe(acac)3) as a catalyst, ethyl alpha-bromophenylacetate (EBPA) as an initiator, ascorbic acid (AsAc) as a reducing agent and triphenyl phosphine (PPh3) as a ligand. The polymerization kinetics showed that the polymerization rate (the conversion reached up to 98.1% after 60 min) was much higher than that mediated by inorganic iron salts and it was affected by the feed of the iron catalyst. Moreover, the kinetic plots were linear, and the molecular weights of the resulting polymers with molecular weight distribution around 1.2, increased linearly with monomer conversions, indicating good features of “living”/controlled radical polymerizations. The end-functionality of the polymers was confirmed by 1H NMR spectroscopy and a chain extension experiment.

Iron-mediated AGET ATRP of styrene and methyl methacrylate using ascorbic acid sodium salt as reducing agent

Atom transfer radical polymerization of styrene (St) and methyl methacrylate (MMA) in bulk and in different solvents using activators generated by electron transfer (AGET ATRP) were investigated in the presence of a limited amount of air using FeCl3·6H2O as the catalyst, ascorbic acid sodium salt (AsAc-Na) as the reducing agent, and a cheap and commercially available tetrabutylammonium bromide (TBABr) as the ligand. It was found that polymerization in THF resulted in shorter induction period than that in bulk and in toluene for AGET ATRP of St, while referring to AGET ATRP of MMA, polymerization in THF showed three advantages compared with that in bulk and toluene: 1) shortening the induction period, 2) enhancing the polymerization rate and 3) having better controllability. The living features of the obtained polymers were verified by chain end analysis and chain-extension experiments.

Iron-mediated AGET ATRP of methyl methacrylate in the presence of polar solvents as ligands

The polar solvents, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), and acetonitrile (CH3CN) were used as ligands for iron(III)-mediated activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate (MMA) with various initiators and reducing agents. Polymerizations were conducted with a molar ratio of [MMA]0/[initiator]0/[FeBr3]0/[reducing agent]0 = 100:1:1:0.5 and a volume ratio of MMA/solvent = 2:1 at 60 °C to investigate the effects of initiator, solvent and reducing agent, and most of the systems showed the typical features of “living”/controlled radical polymerization. In order to get a deeper understanding of the mechanism, the amount of the reducing agent was changed to study the polymerization behavior. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1020–1027

Iron‐mediated AGET ATRP of methyl methacrylate using metal wire as reducing agent

AbstractMethyl methacrylate (MMA) were successfully polymerized by atom transfer radical polymerization with activator generated by electron transfer (AGET ATRP) using copper or iron wire as the reducing agent at 90°C. Well‐controlled polymerizations were demonstrated using an oxidatively stable iron(III) chloride hexahydrate (FeCl3·6H2O) as the catalyst, ethyl 2‐bromoisobutyrate (EBiB) as the initiator, and tetrabutylammonium bromide (TBABr) or triphenylphosphine as the ligand. The polymerization rate was fast and affected by the amount of catalyst and type of reducing agents. For example, the polymerization rate of bulk AGET ATRP with a molar ratio of [MMA]0/[EBiB]0/[FeCl3·6H2O]0/[TBABr]0 = 500/1/0.5/1 using iron wire (the conversion reaches up to 82.2% after 80 min) as the reducing agent was faster than that using copper wire (the conversion reaches up to 86.1% after 3 h). At the same time, the experimental Mn values of the obtained poly(methyl methacrylate) were consistent with the corresponding theoretical ones, and the Mw/Mn values were narrow (∼1.3), showing the typical features of “living”/controlled radical polymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Basic ionic liquid/FeCl3·6H2O as an efficient catalyst for AGET ATRP of methyl methacrylate

AbstractA basic ionic liquid, 1‐butyl‐3‐methyl imidazolium hydroxide ([Bmim]OH), was synthesized and used as the additives in an iron‐mediated atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) of methyl methacrylate in bulk and solution, using FeCl3·6H2O as the catalyst, ethyl 2‐bromoisobutyrate as the initiator, vitamin C (Vc) as the reducing agent, and tetrabutylammonium bromide or tetra‐n‐butylphosphonium bromide as the ligand. Catalytic amount of [Bmim]OH could enhance the polymerization rate and produce poly(methyl methacrylate) with controllable molecular weights and narrow molecular weight distributions (Mw/Mn = 1.3–1.4). The nature of controlled/“living” free radical polymerization in the presence of basic ionic liquid was further confirmed by chain‐extension experiments. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Basic ionic liquids: a new type of ligand and catalyst for the AGET ATRP of methyl methacrylate

Imidazolium-type basic ionic liquids (BILs), including 1-butyl-3-methyl imidazolium hydroxide ([Bmim][OH]), 1-butyl-3-methyl imidazolium phosphate ([Bmim][PO4]), 1-butyl-3-methyl imidazolium carbonate ([Bmim][CO3]), and 1-butyl-3-methyl imidazolium bicarbonate ([Bmim][HCO3]), coordinated by iron chloride (FeCl3·6H2O), were used as both the ligand and catalyst in activators generated by the electron transfer ATRP (AGET ATRP) of methyl methacrylate (MMA) in bulk and solution, without the use of traditional ligands (such as 2,2-bipyridine, tetrabutylammonium bromide, and tetra-n-butylphosphonium bromide). Catalytic amounts of BILs could enhance the initiator efficiency (0.87–0.91) and the polymerization rate, and produce PMMA with controllable molecular weights and narrow molecular weight distributions (Mw/Mn = 1.20–1.40). The nature of the controlled/“living” free radical polymerization in the presence of BILs was confirmed by chain-extension experiments. The ready solubility and availability of BILs enable them to be applied as a new type of ligand and catalyst in iron-mediated AGET ATRP.

Iron(III)-Mediated AGET ATRP of Methyl Methacrylate in the Absence of Additional Ligand

The atom transfer radical polymerization on the mechanism of activator generation by electron transfer (AGET ATRP) of methyl methacrylate (MMA) in N,N-dimethylformamide (DMF) in the presence of the catalytic systems, namely, CCl4-FeCl3-1-acetyl-2-phenylhydrazine (APH) and CCl4-FeCl3-ascorbic acid (AA) is reported. The living feature of this process was confirmed by obtaining well-defined polymers with controlled molecular weight, narrow molecular weight distribution, and a chain-extension experiment. Both reducing agents, an APH as well as an AA, possess the equal kinetic activitis.

Low-Temperature AGET ATRP of Methyl Methacrylate in Ionic Liquid-Based Microemulsions

Sustainable atom transfer radical polymerization of methyl methacrylate (MMA) with activators generated by electron transfer (AGET ATRP) was done using microemulsion polymerization at the relatively low temperature of 30 °C. Ethyl 2-bromoisobutyrate (EBiB) was used as ATRP initiator, ascorbic acid (AA) was used as reducing agent, and CuCl2/N-bis(2-pyridylmethyl)octylamine (BPMOA) was used as catalyst. Microemulsion AGET ATRP of MMA was well-controlled, producing poly(methyl methacrylate) (PMMA) nanoparticles ∼5 nm in diameter and narrow molecular weight distributions (Mw/Mn = 1.20–1.40). After the polymerization and isolation of PMMA, the mixture containing catalysts and ILs was shown to be recoverable and recyclable. Upon replenishment of initiator, reducing agent, and monomer (MMA), AGET ATRP of MMA produced PMMA with reproducible molecular weights and narrow molecular weight distributions, even in the fifth cycle. Thus, this process was demonstrated as being sustainable. Furthermore, use of a new surfa...

A Highly Efficient Iron-Mediated AGET ATRP of Methyl Methacrylate Using Fe(0) Powder as the Reducing Agent

A new method, AGET ATRP mediated by an iron(III) catalyst using Fe(0) powder as a reducing agent and MMA as a model monomer, is reported. The polymerizations can be carried out in the absence or presence of a limited amount of air and show the features of a “living”/controlled radical polymerization. MMA conversions of 90.3 and 80.0% can be obtained in 3.5 and 4.0 h in the absence/presence of a limited amount of air, respectively, for the iron-mediated AGET ATRP with a molar ratio of [MMA]0/[EBiB]0/[FeCl3 · 6H2O]0/[PPh3]0/[Fe(0)]0 = 600:1:0.5:2:0.1 at 90 °C. PMMA with molecular weights of 55 060 and 47 790 g · mol−1 and with molar-mass dispersity of 1.24 and 1.28, respectively, can be obtained correspondingly.

Air‐tolerantly surface‐initiated AGET ATRP mediated by iron catalyst from silica nanoparticles

AbstractWell‐defined polymer‐nanoparticle hybrids were prepared by a newly reported method: atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) mediated by iron catalyst. The kinetics of the surface‐initiated AGET ATRP of methyl methacrylate from the silica nanoparticles, which was mediated by FeCl3/triphenylphosphine as a catalyst complex, ascorbic acid as a reducing agent, N,N‐dimethylformamide as the solvent in the presence of a “sacrificial” (free) initiator, was studied. Both the free and grafted polymers were grown in a control manner. The chemical composition of the nanocomposites was characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Thermogravimetric analysis was used to estimate the content of the grafted organic compound, and transmission electron micrographs was used to observe the core‐shell structure of the hybrid nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2006–2015, 2010

AGET ATRP of Methyl Methacrylate by Silica-Gel-Supported Copper(II) Chloride/2-(8-Heptadecenyl)-4,5-Dihydro-1H-Imidazole-1-Ethylamine

Copper-mediated activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) of methyl methacrylate (MMA) were studied in the presence of 2-(8-heptadecenyl)-4,5-dihydro-1H-imidazole-1-ethylamine (OLC) as ligands that served not only as ligands but also as reducing agents. Well-controlled poly(methyl methacrylate) (PMMA) with narrow molecular weight distribution (M w/M n = 1.29) was prepared in the presence of Cu(II)Cl2/OLC ligand via AGET ATRP. Chain extension of PMMA with MMA was successful and demonstrated well-maintained end-group functionality. Well-controlled PMMA with narrow molecular weight distribution was also prepared via AGET ATRP in the presence of Cu(II) and OLC without any additional reducing agent. A chemically modified silica gel with OLC immobilized on its surface coordinated with CuCl2 was successfully used as a catalyst system for AGET ATRP of methyl methacrylate using ethyl 2-bromopropanoate as initiator. Also well-controlled poly(methyl methacrylate) (PMMA) with narrow molecular weight distribution (M w/M n = 1.46) was prepared in the presence of SiO2–OLC–Cu(II)Cl2 complexes catalyst via AGET ATRP.

AGET ATRP of methyl methacrylate with poly(ethylene glycol) (PEG) as solvent and TMEDA as both ligand and reducing agent

Activator generated by electron transfer atom transfer radical polymerization of methyl methacrylate (MMA) in inexpensive, non-toxic poly(ethylene glycol) (PEG), with air-stable Cu(II)X 2(X = Br, Cl) as the catalyst and N, N, N′, N′-tetramethylethylenediamine (TMEDA) as both ligand and reducing agent was investigated. The polymerizations in PEG proceeded in a well-controlled manner as evidenced by kinetic studies and chain extension results. The polydispersity of the polymer obtained was quite narrow, with a weight-average molecular weight/number-average molecular weight ratio of less than 1.2. Effects of the TMEDA content and the catalysts on polymerization were also investigated, respectively.

AGET ATRP of methyl methacrylate catalyzed by FeCl3/iminodiacetic acid in the presence of air

The recently developed living free-radical polymerization system, atom transfer radical polymerization using activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP), was used for methyl methacrylate (MMA) polymerization in the presence of a limited amount of air, using a novel catalyst system based on iron (FeCl3) complexes with iminodiacetic acid (IDA) and using ascorbic acid (VC) as a reducing agent. The kinetics of AGET ATRPs of MMA with different amounts of VC in the presence of air was investigated. The results of the polymerizations demonstrated the features of “living”/controlled free-radical polymerization such as the number-average molecular weights increasing linearly with monomer conversion and narrow molecular weight distributions (Mw/Mn=1.31–1.44).