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

Methyl 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 M_n values of the obtained poly(methyl methacrylate) were consistent with the corresponding theoretical ones, and the M_w/M_n 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

A 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 (M_w/M_n = 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     

Rate‐enhanced ATRP in the presence of catalytic amounts of base: An example of iron‐mediated AGET ATRP of MMA

The catalytic amount of inorganic bases (i.e., NaOH, Na₃PO₄, NaHCO₃, and Na₂CO₃) and organic bases such as pyridine and triethylamine was used as the additives in an iron‐mediated atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) of a polar monomer methyl methacrylate (MMA) using FeCl₃·6H₂O as the catalyst, ethyl 2‐bromoisobutyrate (EBiB) as the initiator, ascorbic acid (AsAc) as the reducing agent, and tetrabutylammonium bromide (TBABr) as the ligand. All these bases can result in dual enhancement of polymerization rate and controllability over molecular weight while keeping low M_w/M_n values (<1.3) for the resultant polymers. For example, the polymerization rate of AGET ATRP with a molar ratio of [MMA]₀/[EBiB]₀/[FeCl₃·6H₂O]₀/[TBABr]₀/[AsAc]₀/[NaOH]₀ = 500/1/1/2/2/1.5 using NaOH as the additives was more than two times of that without NaOH. The nature of “living”/controlled free radical polymerization in the presence of base was confirmed by chain‐extension experiments. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Novel catalyst system of MCl2/FeCl3·6H2O/PPh3 (M = Ni,Co, or Mn) for the atom transfer radical polymerization of methyl methacrylate

MCl₂ (M = Ni, Co, Sn, or Mn) and PPh₃ together acted as a catalyst for the radical polymerization of methyl methacrylate (MMA) in the presence of ethyl 2‐bromoisobutyrate as an initiator. The four systems all led to conventional radical polymerizations, which yielded polymers with a weight‐average molecular weight/number‐average molecular weight (M_w/M_n) ratio greater than 2.0 and became well controlled when a certain amount of FeCl₃·6H₂O was added. The polymerizations of MMA catalyzed by these four FeCl₃‐modified catalyst systems provided well‐defined polymers with low polydispersities (M_w/M_n < 1.28). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2625–2631, 2005     

A novel approach to modify poly(vinylidene fluoride) via iron‐mediated atom transfer radical polymerization using activators generated by electron transfer

Iron‐mediated atom transfer radical polymerization using activators generated by electron transfer directly from the secondary fluorine atoms on the poly(vinylidene fluoride) (PVDF) backbone, using methyl methacrylate (MMA) and poly (ethylene glycol) methyl ether methacrylate (PEGMA) as the monomers, FeCl₃·6H₂O as the catalyst, PPh₃ as the ligand, and vitamin C as the reducing agent, was demonstrated in the presence of limited amounts of air. The successful syntheses of the corresponding graft copolymers PVDF‐g‐PMMA and PVDF‐g‐PPEGMA were characterized by nuclear magnetic resonance, Fourier transform infrared and X‐ray photoelectron spectroscopy, respectively. The graft copolymers PVDF‐g‐PPEGMA can be readily cast into porous hydrophilic microfiltration membranes by phase inversion in an aqueous medium. The morphologies were characterized by scanning electron microscopy. The surface and bulk hydrophilicity were evaluated on the basis of static water contact angle and the steady adsorption of bovine serum albumin. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Alumina additives for fast iron‐mediated AGET ATRP of MMA using onium salt as ligand

Three kinds of alumina (acidic, neutral, and basic Al₂O₃) were effective as additives for the control and rate enhancement of iron‐mediated AGET (activators generated by electron transfer) ATRP (atom transfer radical polymerization) of methyl methacrylate (MMA) in the presence of limited amount of air, using FeCl₃·6H₂O as the catalyst, tetrabutylammonium bromide or tetra‐n‐butylphosphonium bromide as the ligand, ethyl 2‐bromoisobutyrate as the initiator, and ascorbic acid as the reducing agent. The conversion could be up to 83.9% in the case of basic Al₂O₃ and 75.3% with neutral Al₂O₃ only in 13 h, respectively, whereas no polymer could be obtained even in 50 h without additives. The polymers obtained with neutral and basic Al₂O₃ had controlled molecular weights and low M_w/M_n values (～1.2). Tacticities of the as‐prepared PMMA in the presence of these three kinds of Al₂O₃ were consistent with that obtained from conventional free‐radical polymerization of MMA. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

In situ Cu(0) catalyzed SET‐LRP: The first attempt

In this work, single electron transfer‐living radical polymerization (SET‐LRP) was catalyzed by in situ Cu(0) generated from copper sulphate pentahydrate (CuSO₄·5H₂O) and hydrazine hydrate (N₂H₄·H₂O) at 25 °C. The polymerization occurred smoothly with moderate controllability: the polymerization rates increased by the increases of N₂H₄·H₂O, and the initiator concentration had an optimal value on the polymerization rate; the number‐average molecular weights (M_n,GPC) increased with monomer conversions and polydispersities were below 1.40. The M_n,GPC deviated much from theoretical ones with about 50% polymer chain‐end fidelities. Some side reactions stemming from the strong reduction performance of N₂H₄·H₂O were responsible for the mildly controlled polymerizations. This polymerization can be conducted in SET‐LRP unfavorable solvents or in bulk, such as toluene and tetrahydrofuran, owing to the H₂O contained in CuSO₄·5H₂O and N₂H₄·H₂O. On account of the utilization of CuSO₄·5H₂O, an inactive Cu(II) compounds in LRP area, this work confirmed from experimental level that it was Cu(0) which acted as activator and mediator in SET‐LRP. This work provided a first example of in situ Cu(0) catalyzing SET‐LRP with CuSO₄·5H₂O as a copper source. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Iron(III)‐mediated AGET ATRP of styrene using tris(3,6‐dioxaheptyl)amine as a ligand

A commercially available tris(3,6‐dioxaheptyl)amine (TDA‐1) was used as a novel ligand for activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) of styrene in bulk or solution mediated by iron(III) catalyst in the presence of a limited amount of air. FeCl₃ · 6H₂O and (1‐bromoethyl)benzene (PEBr) were used as the catalyst and initiator, respectively; and environmentally benign ascorbic acid (VC) was used as the reducing agent. The polymerizations show the features of “living”/controlled free‐radical polymerizations and well‐defined polystyrenes with molecular weight M_n = 2400–36,500 g/mol and narrow polydispersity (M_w/M_n = 1.11–1.29) were obtained. The “living” feature of the obtained polymer was further confirmed by a chain‐extension experiment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2002–2008, 2009     

Reverse atom transfer radical polymerization of methyl methacrylate with a new catalytic system,FeCl3/isophthalic acid

A new catalytic system, FeCl₃/isophthalic acid, was successfully used in the reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) in the presence of a conventional radical initiator, 2,2′‐azo‐bis‐isobutyrontrile. Well‐defined poly(methyl methacrylate) (PMMA) was synthesized in an N,N‐dimethylformamide solvent at 90–120 °C. The polymerization was controlled up to a molecular weight of 50,000, and the polydispersity index was 1.4. Chain extension was performed to confirm the living nature of the polymer. The kinetics of the RATRP of MMA with FeCl₃/isophthalic acid as the catalyst system was investigated. The apparent activation energy was 10.47 kcal/mol. The presence of the end chloride atom on the resulting PMMA was demonstrated by ¹H NMR spectroscopy. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 765–774, 2001     

A novel fluorine‐containing graft copolymer bearing perfluorocyclobutyl aryl ether‐based backbone and poly(methyl methacrylate) side chains

A series of novel graft copolymers consisting of perfluorocyclobutyl aryl ether‐based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of thermal [2π + 2π] step‐growth cycloaddition polymerization of aryl bistrifluorovinyl ether monomer and atom transfer radical polymerization (ATRP) of methyl methacrylate. A new aryl bistrifluorovinyl ether monomer, 2‐methyl‐1,4‐bistrifluorovinyloxybenzene, was first synthesized in two steps from commercially available reagents, and this monomer was homopolymerized in diphenyl ether to provide the corresponding perfluorocyclobutyl aryl ether‐based homopolymer with methoxyl end groups. The fluoropolymer was then converted to ATRP macroinitiator by the monobromination of the pendant methyls with N‐bromosuccinimide and benzoyl peroxide. The grafting‐from strategy was finally used to obtain the novel poly(2‐methyl‐1,4‐bistrifluorovinyloxybenzene)‐g‐poly(methyl methacrylate) graft copolymers with relatively narrow molecular weight distributions (M_w/M_n ≤ 1.46) via ATRP of methyl methacrylate at 50 °C in anisole initiated by the Br‐containing macroinitiator using CuBr/dHbpy as catalytic system. These fluorine‐containing graft copolymers can dissolve in most organic solvents. This is the first example of the graft copolymer possessing perfluorocyclobutyl aryl ether‐based backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Atom transfer radical polymerization of 6‐O‐methacryloyl‐1,2;3,4‐di‐O‐isopropylidene‐D‐galactopyranose in solution

A detailed exploration of the atom transfer radical polymerization (ATRP) of a sugar‐carrying monomer, 6‐O‐methacryloyl‐1,2;3,4‐di‐O‐isopropylidene‐D‐galactopyranose (MAIPGal) was performed. The factors pertinent to ATRP, such as initiators, ligands, catalysts, and temperature were optimized to obtain good control over the polymerization. The kinetics were examined in detail when the polymerization was initiated by methyl 2‐bromoisopropionate (2‐MBP), ethyl 2‐bromoisobutyrate (2‐EBiB), or a macroinitiator, [α‐(2‐bromoisobutyrylate)‐ω‐methyl PEO] (PEO–Br), with bipyridine (bipy) as the ligand at 60 °C or by 2‐EiBB with N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as the ligand at room temperature (23 °C). The effects of the catalysts (CuBr and CuCl) were also investigated. We demonstrate that the successful ATRP of MAIPGal can be achieved for 2‐EBiB/CuBr/bipy and 2‐MBP/CuCl/bipy at 60 °C and for 2‐EBiB/CuBr/PMDETA at room temperature. The initiation by 2‐EBiB at room temperature with PMDETA as the ligand should be the most optimum operation for its moderate condition and suppression of many side reactions. Chain extension of P(MAIPGal) prepared by ATRP with methyl methacrylate (MMA) as the second monomer was carried out and a diblock copolymer, P(MAIPGal)‐b‐PMMA, was obtained. Functional polymers, poly(D‐galactose 6‐methacrylate) (PGMA), PEO‐b‐PGMA, and PGMA‐b‐PMMA were obtained after removal of the protecting groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 752–762, 2005     

Atom transfer radical polymerization of styrene and methyl methacrylate catalyzed by FeCl2/iminodiacetic acid

The atom transfer radical polymerization of styrene and methyl methacrylate with FeCl₂/iminodiacetic acid as the catalyst system in bulk was successfully implemented at 70 and 110 °C, respectively. The polymerization was controlled: the molecular weight of the resultant polymer was close to the calculated value, and the molecular weight distribution was relatively narrow (weight‐average molecular weight/number‐average molecular weight ∼ 1.5). Block copolymers of polystyrene‐b‐poly(methyl methacrylate) and poly(methyl methacrylate)‐b‐poly(methyl acrylate) were successfully synthesized, confirming the living nature of the polymerization. A small amount of water added to the reaction system increased the reaction rate and did not affect the living nature of the polymerization system. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4308–4314, 2000     

“Living”/controlled free radical polymerization of MMA in the presence of cobalt(II) 2‐ethylhexanoate: A switch from RAFT to ATRP mechanism

A metal complex, cobalt(II) 2‐ethylhexanoate (CEH), was added to the system of thermal‐initiated reversible addition‐fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) with 2‐cyanoprop‐2‐yl 1‐dithionaphthalate (CPDN) as the RAFT agent at 115 °C. The polymerization rate was remarkably enhanced in the presence of CEH in comparison with that in the absence of CEH, and the increase of the CPDN concentration also accelerated the rate of polymerization. The polymerization in the concurrence of CPDN and CEH demonstrated the characters of “living”/controlled free radical polymerization: the number‐average molecular weights (M_n) increasing linearly with monomer conversion, narrow molecular weight distributions (M_w/M_n) and obtained PMMA end‐capped with the CPDN moieties. Meanwhile, CEH can also accelerate the rate of RAFT polymerization of MMA using the PMMA as macro‐RAFT agent instead of CPDN. Similar polymerization profiles were obtained when copper (I) bromide (CuBr)/N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine was used instead of CEH. Extensive experiments in the presence of butyl methacrylate, bis(cyclopentadienyl) cobalt(II) and cumyl dithionaphthalenoate were also conducted; similar results as those of MMA/CPDN/CEH system were obtained. A transition of the polymerization mechanism, from RAFT process without CEH addition to atom transfer radical polymerization in the presence of CEH, was possibly responsible for polymerization profiles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5722–5730, 2007     

N,N,N′,N′,N″‐penta(methyl acrylate)diethylenetriamine: A novel ligand for atom transfer radical polymerization of methyl methacrylate

A novel ligand, N,N,N′,N′,N″‐penta (methyl acrylate) diethylenetriamine (MA₅‐DETA), was synthesized by the reaction of diethylenetriamine with methyl acrylate in almost quantitive yield. The polymerizations of methyl methacrylate with MA₅‐DETA as the ligand and α,α‐dichlorotoluene (DCT) and ethyl 2‐bromoisobutyrate (2‐EBiB) as the initiators, respectively, under different conditions were examined. The polymerization with CuCl/MA₅‐DETA/DCT was closely controlled in bulk and gave polymers with quite narrow molecular weight distributions (M_w/M_n's) of 1.16–1.29. The polymerization with the system CuBr/MA₅‐DETA/EBiB in bulk gave high activity. However, the system was not well controlled and gave the polymers with M_w/M_n = 1.35–1.53. The solution polymerization in anisole with CuBr/MA₅‐DETA/EBiB showed a better‐controlled nature. Moreover, the addition of CuBr₂ into the aforementioned system can further improve its controllability. The M_w/M_n's of the resulting polymers ranged from 1.11 to 1.21. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1963–1969, 2004     

Synthesis and characterization of amphiphilic triblock copolymers by iron‐mediated atom transfer radical polymerization

The atom transfer radical polymerization of methyl methacrylate (MMA) and n‐butyl methacrylate (n‐BMA) was initiated by a poly(ethylene oxide) chloro telechelic macroinitiator synthesized by esterification of poly(ethylene oxide) (PEO) with 2‐chloro propionyl chloride. The polymerization, carried out in bulk at 90 °C and catalyzed by iron(II) chloride tetrahydrate in the presence of triphenylphosphine ligand (FeCl₂ · 4H₂O/PPh₃), led to A–B–A amphiphilic triblock copolymers with MMA or n‐BMA as the A block and PEO as the B block. A kinetic study showed that the polymerization was first‐order with respect to the monomer concentration. Moreover, the experimental molecular weights of the block copolymers increased linearly with the monomer conversion, and the molecular weight distribution was acceptably narrow at the end of the reaction. These block copolymers turned out to be water‐soluble through the adjustment of the content of PEO blocks (PEO content >90% by mass). When the PEO content was small [monomer/macroinitiator molar ratio (M/I) = 300], the block copolymers were water‐insoluble and showed only one glass‐transition temperature. With an increase in the concentration of PEO (M/I = 100 or 50) in the copolymer, two glass transitions were detected, indicating phase separation. The macroinitiator and the corresponding triblock copolymers were characterized with Fourier transform infrared, proton nuclear magnetic resonance, size exclusion chromatography analysis, dynamic mechanical analysis, and differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5049–5061, 2005     

Atom transfer radical copolymerization of acrylonitrile and ethyl methacrylate at ambient temperature

Copolymerization of acrylonitrile (AN) and ethyl methacrylate (EMA) using copper‐based atom transfer radical polymerization (ATRP) at ambient temperature (30 °C) using various initiators has been investigated with the aim of achieving control over molecular weight distribution. The effect of variation of concentration of the initiator, ligand, catalyst, and temperature on the molecular weight distribution and kinetics were investigated. No polymerization at ambient temperature was observed with N,N,N′,N′,N″‐pentamethyldiethylenetriamine (PMDETA) ligand. The rate of polymerization exhibited 0.86 order dependence with respect to 2‐bromopropionitrile (BPN) initiator. The first‐order kinetics was observed using BPN as initiator, while curvature in first‐order kinetic plot was obtained for ethyl 2‐bromoisobutyrate (EBiB) and methyl 2‐bromopropionate (MBP), indicating that termination was taking place. Successful polymerization was also achieved with catalyst concentrations of 25 and 10% relative to initiator without loss of control over polymerization. The optimum [bpy]₀/[CuBr]₀ molar ratio for the copolymerization of AN and EMA through ATRP was found to be 3/1. For three different in‐feed ratios, the variation of copolymer composition (F_AN) with conversion indicated toward the synthesis of copolymers having slight changes in composition with conversion. The high chain‐end functionality of the synthesized AN‐EMA copolymers was verified by further chain extension with methyl acrylate and styrene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1975–1984, 2006     

2‐[(Diphenylphosphino)methyl]pyridine as ligand for iron‐based atom transfer radical polymerization

2‐[(Diphenylphosphino)methyl]pyridine (DPPMP) was successfully used as a bidentate ligand in the iron‐mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) with various initiators and solvents. The effect of the catalytic system on ATRP was studied systematically. Most of the polymerizations with DPPMP ligand were well controlled with a linear increase in the number‐average molecular weights (M_n) versus conversion and relatively low molecular weight distributions (M_w/M_n = 1.10–1.3) being observed throughout the reactions, and the measured molecular weights matched the predicted values. Initially added iron(III) bromide improved the controllability of the polymerization reactions in terms of molecular weight control. The ratio of ligand to metal influenced the controllability of ATRP system, and the optimum ratio was found to be 2:1. It was shown that ATRP of MMA with FeX₂/DPPMP catalytic system (X = Cl, Br) initiated by 2‐bromopropionitrile (BPN) was controlled more effectively in toluene than in polar solvents. The rate of polymerization increased with increasing the polymerization temperature and the apparent activation energy was calculated to be 56.7 KJ mol^?1. In addition, reverse ATRP of MMA was able to be successfully carried out using AIBN in toluene at 80 °C. Polymerization of styrene (St) was found to be controlled well by using the PEBr/FeBr₂/DPPMP system in DMF at 110 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2922–2935, 2008     

Synthesis of polyacrylonitrile via reverse atom transfer radical polymerization catalyzed by FeCl3/isophthalic acid

FeCl₃ coordinated by isophthalic acid was first used as a catalyst in the azobisisobutyronitrile‐initiated reverse atom transfer radical polymerization of acrylonitrile. N,N‐Dimethylformamide was used as a solvent to improve the solubility of the ligand. An FeCl₃‐to‐isophthalic acid ratio of 0.5 not only gave the best control of the molecular weight and its distribution but also provided rather a rapid reaction rate. The effects of different solvents on the polymerization of acrylonitrile were also investigated. The rate of the polymerization in N,N‐dimethylformamide was faster than that in propylene carbonate and toluene. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. The rate of polymerization increased with increasing polymerization temperature, and the apparent activation energy was calculated to be 59.9 kJ mol^?1. Reverse atom transfer radical polymerization was first used to successfully synthesize acrylonitrile polymers with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.22. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 219–225, 2006     

Poly(methyl methacrylate‐co‐pentaerythritol tetraacrylate‐co‐butyl methacrylate)‐g‐polystyrene: Synthesis and high oil‐absorption property

Well‐defined high oil‐absorption resin was successfully prepared via living radical polymerization on surface of polystyrene resin‐supported N‐chlorosulfonamide group utilizing methyl methacrylate and butyl methacrylate as monomers, ferric trichloride/iminodiacetic acid (FeCl₃/IDA) as catalyst system, pentaerythritol tetraacrylate as crosslinker, and L ‐ascorbic acid as reducing agent. The polymerization proceeded in a “living” polymerization manner as indicated by linearity kinetic plot of the polymerization. Effects of crosslinker, catalyst, macroinitiator, reducing agent on polymerization and absorption property were discussed in detail. The chemical structure of sorbent was determined by FTIR spectrometry. The oil‐absorption resin shows a toluene absorption capacity of 21 g g^?1. The adsorption of oil behaves as pseudo‐first‐order kinetic model rather than pseudo‐second‐order kinetic model. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis of styrene/methyl methacrylate copolymers by atom transfer radical polymerization: 2D NMR investigations

Copolymers of styrene and methyl methacrylate were synthesized by atom transfer radical polymerization using methyl 2‐bromopropionate as initiator and CuBr/N,N,N′,N′,N″‐pentamethyldiethylenetriamine as catalyst. Molecular weight distributions were determined by gel permeation chromatography. The composition of the copolymer was determined by ¹H NMR. The comonomer reactivity ratios, determined by both Kelen–Tudos and nonlinear error‐in‐variables methods, were r_S = 0.64 ± 0.08, r_M = 0.63 ± 0.08 and r_S = 0.66, r_M = 0.65, respectively. The α‐methyl and carbonyl carbon resonances were found to be compositionally and configurationally sensitive. Complete spectral assignments of the ¹H and ¹³C NMR spectra of the copolymers were done by distortionless enhancement by polarization transfer and two‐dimensional NMR techniques such as heteronuclear single quantum coherence and heteronuclear multiple quantum coherence. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2076–2085, 2006