Effects of the solvent polarity on the atom transfer radical polymerization of methyl methacrylate initiated by 4‐(chloromethyl)phenyltrimethoxysilane

The controllability of the atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N‐dimethylformamide and the nonpolar solvent xylene with 4‐(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′‐bipyridine and CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as catalyst systems was studied. Gel permeation chromatography analysis established that in the nonpolar solvent xylene, much better control of the molecular weight and polydispersity of poly(methyl methacrylate) was achieved with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system than with the CuCl/2,2′‐bipyridine as catalyst system. In the polar solvent N,N‐dimethylformamide, unlike in xylene, the polymerization was more controllable with the CuCl/2,2′‐bipyridine catalyst system than with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2751–2754, 2007     

Copper‐based reverse ATRP process for the controlled radical polymerization of methyl methacrylate

A series of copper‐based reverse atom transfer radical polymerizations (ATRP) were carried out for methyl methacrylate (MMA) at same conditions (in xylene, at 80°C) using N,N,N′,N′‐teramethylethylendiamine (TMEDA), N,N,N′,N′,N′‐pentamethyldiethylentriamine (PMDETA), 2‐2′‐bipyridine, and 4,4′‐Di(5‐nonyl)‐2,2′‐bipyridine as ligand, respectively. 2,2′‐azobis(isobutyronitrile) (AIBN) was used as initiator. In CuBr₂/bpy system, the polymerization is uncontrolled, because of the poor solubility of CuBr₂/bpy complex in organic phase. But in other three systems, the polymerizations represent controlled. Especially in CuBr₂/dNbpy system, the number‐average molecular weight increases linearly with monomer conversion from 4280 up to 14,700. During the whole polymerization, the polydispersities are quite low (in the range 1.07–1.10). The different results obtained from the four systems are due to the differences of ligands. From the point of molecular structure of ligands, it is very important to analyze deeply the two relations between (1) ligand and complex and (2) complex and polymerization. The different results obtained were discussed based on the steric effect and valence bond theory. The results can help us deep to understand the mechanism of ATRP. The presence of the bromine atoms as end groups of the poly(methyl methacrylate) (PMMA) obtained was determined by ¹H‐NMR spectroscopy. PMMA obtained could be used as macroinitiator to process chain‐extension reaction or block copolymerization reaction via a conventional ATRP process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Reverse atom transfer radical polymerization of stearyl methacrylate using 2,2′‐azobisisobutyronitrile as the initiator

The living/controlled radical polymerization of stearyl methacrylate was carried out with a conventional radical initiator (2,2′‐azobisisobutyronitrile) in N,N‐dimethylformamide in the presence of a 2,2′‐bipyridine complex of hexakis(N,N‐dimethylformamide)iron(III) perchlorate. The polymerization mechanism was thought to proceed through a reverse atom transfer radical polymerization. The molecular weights of resulting poly(stearyl methacrylate) increased with conversion, and the resulting molecular weight distributions were quite narrow. The rates of polymerization exhibited first‐order kinetics with respect to the monomer. A probable reaction mechanism for the polymerization system is postulated to explain the observed results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1236–1245, 2002     

Synthesis and characterization of poly(n‐butyl methacrylate)‐b‐polystyrene diblock copolymers by atom transfer radical emulsion polymerization

Poly(n‐butyl methacrylate) (PBMA)‐b‐polystyrene (PSt) diblock copolymers were synthesized by emulsion atom transfer radical polymerization (ATRP). PBMA macroinitiators that contained alkyl bromide end groups were obtained by the emulsion ATRP of n‐butyl methacrylate with BrCH₃CHCOOC₂H₅ as the initiator; these were used to initiate the ATRP of styrene (St). The latter procedure was carried out at 85°C with CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as the catalyst and polyoxyethylene(23) lauryl ether as the surfactant. With this technique, PBMA‐b‐PSt diblock copolymers were synthesized. The polymerization was nearly controlled; the ATRP of St from the macroinitiators showed linear increases in number‐average molecular weight with conversion. The block copolymers were characterized with IR spectroscopy, ¹H‐NMR, and differential scanning calorimetry. The effects of the molecular weight of the macroinitiators, macroinitiator concentration, catalyst concentration, surfactant concentration, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP are also reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2123–2129, 2005     

Atom transfer radical polymerization of n‐butyl methacrylate in an aqueous dispersed system

Atom transfer radical polymerization of n‐butyl methacrylate (BMA) was conducted in an aqueous dispersed system with different kinds of copper complexes. The partitioning behavior of the copper complexes, including CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipydine (dNbpy), CuCl₂/dNbpy, CuCl/2,2′‐bipydine (bpy), CuCl₂/bpy, CuCl/bis(N,N′‐dimethylaminoethyl)ether (bde), and CuCl₂/bde between the monomer (BMA), and water was studied in detail with ultraviolet‐visible spectroscopy. The results show that with a less hydrophobic ligand, such as bpy or bde, most of the Cu(I) or the Cu(II) complexes migrated from the BMA phase to the aqueous phase, the atom transfer equilibrium was destroyed, and the polymerization was nearly not controlled; it converted to classical emulsion polymerization. As to the very hydrophobic ligand dNbpy, although the partitioning study of the copper complexes indicated that not all the copper species were restricted to the organic phase, the linear correlation between the molecular weight and the monomer conversion and the narrow polydispersities confirmed that the polymerization was still quite well controlled. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3175–3179, 2003     

Synthesis and characterization of poly(vinyl chloride‐co‐vinyl acetate)‐graft‐poly[(meth)acrylates] by atom transfer radical polymerization

The graft polymerization of methyl methacrylate and butyl acrylate onto poly(vinyl chloride‐co‐vinyl acetate) with atom transfer radical polymerization (ATRP) was successfully carried out with copper(I) thiocyanate/N,N,N′,N′,N″‐pentamethyldiethylenetriamine and copper(I) chloride/2,2′‐bipyridine as catalysts in the solvent N,N‐dimethylformamide. For methyl methacrylate, a kinetic plot of ln([M]₀/[M]) (where [M]₀ is the initial monomer concentration and [M] is the monomer concentration) versus time for the graft polymerization was almost linear, and the molecular weight of the graft copolymer increased with increasing conversion, this being typical for ATRP. The formation of the graft polymer was confirmed with gel permeation chromatography, ¹H‐NMR, and Fourier transform infrared spectroscopy. The glass‐transition temperature of the copolymer increased with the concentration of methyl methacrylate. The graft copolymer was hydrolyzed, and its swelling capacity was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 183–189, 2005     

Studies on atom transfer radical emulsion polymerization of n‐butyl methacrylate

Atom transfer radical polymerization (ATRP) of n‐butyl methacrylate (BMA) in water‐borne media, catalyzed and initiated by CuCl/4,4′‐di (5‐nonyl)‐2,2′‐bipyridine (dNbpy) and Ethyl 2‐bromopropinate (BrCH₃CHCOOC₂H₅₎ was conducted. The influence of several factors, such as the amount of surfactant, catalyst, initiator and the reaction time, temperature on the stability of the latexes and the control of the polymerization was investigated. The nucleation mechanism of the latexes, thermodynamic data and activation parameters for the ATRP emulsion polymerization of BMA were also reported. POLYM. ENG. SCI. 45:297–302, 2005. © 2005 Society of Plastics Engineers.     

New fluorous bipyridine ligands for copper‐catalyzed atom transfer radical polymerization of methyl methacrylate in the thermomorphic mode

The atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) is often carried out under homogeneous conditions, so the residual metal catalyst in the polymer often influences the quality of the polymer and causes environmental pollution in the long run. Novel CuBr/4,4′‐bis(R_fCH₂OCH₂)‐2,2′‐bpy complexes (R_f = n‐C₉F₁₉, n‐C₁₀F₂₁, or n‐C₁₁F₂₃; 2,2′‐bpy = 2,2′‐bipyridine) are insoluble in toluene at room temperature yet readily dissolve in toluene at elevated temperatures to form homogeneous phases for use as catalysts in the ATRP reaction, and the Cu complexes precipitate again upon cooling. The CuBr/4,4′‐bis(n‐C₉F₁₉CH₂OCH₂)‐2,2′‐bpy system produced the best results (e.g., polydispersity index by gel permeation chromatography = 1.26–1.41), in that the residual Cu content in the polymer was as low as 19.3 ppm when the ATRP of MMA was carried out in the thermomorphic mode. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Kinetic study of the atom transfer radical polymerization of n‐docosyl acrylate

The atom transfer radical polymerization (ATRP) of n‐docosyl acrylate (DA) was studied at 80°C in N,N‐dimethylformamide using the carbon tetrabromide/FeCl₃/2,2′‐bipyridine (bpy) initiator system in the presence of 2,2′‐azobisisobutyronitrile (AIBN) as the source of reducing agent. The rate of polymerization exhibits first‐order kinetics with respect to the monomer. The linear relationship between the molecular weight of the resulting poly(n‐docosyl acrylate) with conversion and the narrow polydispersity of the polymers indicates the living characteristics of the polymerization reaction. The significant effect of AIBN on the ATRP of DA was studied keeping [FeCl₃]/[bpy] constant. A probable reaction mechanism for the polymerization system is postulated to explain the observed results. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2147–2154, 2005     

Highly trans‐1,4‐specific polymerization of 1,3‐butadiene catalyzed by [2,6‐bis{(4S)‐ (−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine] chromium complex activated with modified methylaluminoxane

Chromium complexes with N,N,N‐tridentate ligands, LCrCl₃ (L = 2,6‐bis{(4S)‐(?)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine ( 1 ), 2,2′:6′,2″‐terpyridine ( 2 ), and 4,4′,4″‐tri‐tert‐butyl‐2,2′:6′,2″‐terpyridine ( 3 )), were prepared. The structures of 1 and 2 were determined by X‐ray crystallography. Upon activation with modified methylaluminoxane (MMAO), 1 catalyzed the polymerization of 1,3‐butadiene, while 2 and 3 was inactive. The obtained poly(1,3‐butadiene) obtained with 1 ‐MMAO was found to have completely trans‐1,4 structure. The 1 ‐MMAO system also showed catalytic activity for the polymerization of isoprene to give polyisoprene with trans‐1,4 (68%) and cis‐1,4 (32%) structure. Copyright © 2011 Society of Chemical Industry     

High‐molecular‐weight polyacrylonitrile by atom transfer radical polymerization

A single‐pot atom transfer radical polymerization was used for the first time to successfully synthesize polyacrylonitrile with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.18. This was achieved with CuBr/isophthalic acid as the catalyst, 2‐bromopropionitrile as the initiator, and N,N‐dimethylformamide as the solvent. The effects of the solvent on the polymerization of acrylonitrile were also investigated. The induction period was shorter in N,N‐dimethylformamide than in propylene carbonate and toluene, and the rate of the polymerization in N,N‐dimethylformamide was fastest. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. When chlorine was used in either the initiator or the catalyst, the rate of polymerization showed a trend of decreasing, and the molecular weight deviated from the theoretical predication significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3372–3376, 2006     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Atom transfer radical polymerization of methyl methacrylate initiated with a macroinitiator of poly(vinyl acetate)

Well‐defined poly(vinyl acetate‐b‐methyl methacrylate) block copolymers were successfully synthesized by the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in p‐xylene with CuBr as a catalyst, 2,2′‐bipyridine as a ligand, and trichloromethyl‐end‐grouped poly(vinyl acetate) (PVAc–CCl₃) as a macroinitiator that was prepared via the telomerization of vinyl acetate with chloroform as a telogen. The block copolymers were characterized with gel permeation chromatography, Fourier transform infrared, and ¹H‐NMR. The effects of the solvent and temperature on ATRP of MMA were studied. The control over a large range of molecular weights was investigated with a high [MMA]/[PVAc–CCl₃] ratio for potential industry applications. In addition, the mechanism of the polymerization was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1089–1094, 2006     

Synthesis and characterization of new polyureas derived from 4‐(4′‐Methoxyphenyl)urazole

4‐(4′‐Methoxyphenyl)urazole (MPU) was prepared from 4‐methoxybenzoic acid in five steps. The reaction of monomer MPU with n‐isopropylisocyanate was performed at room temperature in N,N‐dimethylformamide solution, and the resulting bis‐urea derivative was obtained in high yield and was finally used as a model for polymerization reaction. The step‐growth polymerization reactions of monomer MPU with hexamethylene diioscyanate, isophorone diioscyanate, and toluene‐2,4‐diioscyanate were performed in N,N‐dimethylacetamide solution in the presence of pyridine as a catalyst. The resulting novel polyureas have an inherent viscosity (η_inh) in a range of 0.07–0.21 dL/g in DMF and sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and TGA. Some physical properties and structural characterization of these novel polyureas are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1141–1146, 2002     

Synthesis of well‐defined poly(methyl methacrylate) nanoparticles by reverse atom transfer radical polymerization in a microemulsion

Well‐defined poly(methyl methacrylate) (PMMA) with an α‐isobutyronitrile group and an ω‐bromine atom as the end groups was synthesized by the microemulsion polymerization of methyl methacrylate (MMA) at 70°C with a 2,2′‐azobisisobutyronitrile/CuBr₂/2,2′‐bipyridine system. The conversion of the polymerization reached 81.9%. The viscosity‐average molecular weight of PMMA was high (380,000), and the polydispersity index was 1.58. The polymerization of MMA exhibited some controlled radical polymerization characteristics. The mechanism of controlled polymerization was studied. The presence of hydrogen and bromine atoms as end groups of the obtained PMMA was determined by ¹H‐NMR spectroscopy. The shape and size of the final polymer particles were analyzed by scanning probe microscopy, and the diameters of the obtained particles were usually in the range of 60–100 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3670–3676, 2006     

Single‐ and two‐step procedures of AGET emulsion ATRP of methyl methacrylate in a well‐mixed batch reactor

This study investigates the atom transfer radical emulsion polymerization of methyl methacrylate in a 2 L well‐mixed stirred batch reactor using activators generated by electron transfer as the initiation technique. The polymerization was carried out with ethyl‐2‐bromoisobutyrate as the initiator, copper bromide with 4,4′‐di‐5‐nonyl‐2,2′‐bipyridine as the catalyst system, Brij 98 as the surfactant, and ascorbic acid as the reducing agent. The reaction was carried out at constant temperature in the range of 50 to 70 °C under a blanket of nitrogen to minimize the presence of air in the system. Polymerizations were carried out according to single‐step and two‐step procedures. The coagulation was found to be a major problem, especially at high monomer conversion. However, adding more surfactant and lowering the reaction temperature weakened the effect of the coagulation but at the expense of the low monomer conversion. Measurement of molecular weight distribution and ? using gel permeation show that the two‐step techniques produced polymers with living features of atom transfer radical emulsion polymerization much better than those in the single‐step procedure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45308.     

ICAR ATRP of methyl methacrylate catalyzed by FeCl3·6H2O/succinic acid

In this work, methyl methacrylate (MMA) was polymerized by initiator for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) method to obtain low molecular weight living polymers. The ATRP initiator was ethyl 2‐bromoisobutyrate, the catalyst ligand complex system was FeCl₃·6H₂O/succinic acid, and the conventional radical initiator 2,2′‐azobisisobutyronitrile was used as a thermal radical initiator. Polymers with controlled molecular weight were obtained with ppm level of Fe catalyst complex at 90°C in N,N‐dimethylformamide. The polymer was characterized by nuclear magnetic resonance (NMR). The molecular weight and molecular weight distribution of the obtained poly (methyl methacrylate) were measured by gel permeation chromatography method. The kinetics results indicated that ICAR ATRP of MMA was a “living”/controlled polymerization, corresponding to a linear increase of molecular weights with the increasing of monomer conversion and a relatively narrow polydispersities index. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of novel bipyridyl ligands and application in preparation of polyketone

In this article, novel 2,2′‐bipyridyl derivatives were synthesized and the excellent bipyridyl ligands were chosen as catalyst to apply in the copolymerization of carbon monoxide (CO) and styrene (ST) to prepare polyketone. 4,4′‐Dicarboxyl‐2,2′‐bipyridine(4,4′‐dcpy) was synthesized by use of synthesized 4,4′‐dimethyl‐2,2′‐bipyridine(4,4′‐dmpy). The products (4,4′‐dmpy and 4,4′‐dcpy) were characterized by melting point, NMR, IR, GC‐MS, and elemental analysis. The effects of different ligands and various reaction conditions incuding the usage of ligand, p‐toluenesulfonic acid, solvent, p‐benzoquinone, the CO pressure, and reaction temperature on catalytic activity of the copolymerization were investigated. The catalytic activity of 4,4′‐dmpy, 4,4′‐dcpy and 2,2′‐bipyridine were compared. The results showed that the addition of the electron‐donating substituent can enhance catalytic activity, with the sequence as follows: 4,4′‐ dimethyl‐2,2′‐bipyridine > 2,2′‐bipyridine > 4, 4′‐carboxy 2,2′‐ bipyridine. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000–000, 2012     

Reverse atom transfer radical polymerization of acrylonitrile under microwave irradiation

Reverse atom transfer radical polymerization was first used to successfully synthesize polyacrylonitrile under microwave irradiation. FeCl₃, coordinated by isophthalic acid, was used as the catalyst, and 2,2′‐azobisisoheptonitrilewas used as the initiator. N,N‐Dimethylformamide was used as the solvent to improve the solubility of the ligand. Under the same experimental conditions, the apparent rate constant under microwave irradiation was higher than that under conventional heating. The polymerization not only showed the best control of the molecular weight and its distribution but also provided a rather rapid reaction rate with the [acrylonitrile]/[2,2′‐azobisisoheptonitrile]/[FeCl₃]/[isophthalic acid] ratio of 300 : 1 : 1 : 2. The polymers obtained were used as macroinitiators to initiate the chain extension and successfully synthesize acrylonitrile polymers with a molecular weight higher than 50,000 and a narrow polydispersity as low as 1.30. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of telechelic C60 end‐capped polymers under microwave irradiation

Bromo‐Double‐Terminated polystyrene (Br‐PSt‐Br) and poly(methyl methacrylate) (Br‐PMMA‐Br) with predesigned molecular weight and narrow polydispersity were prepared by atom transfer radical polymerization (ATRP) using the initiating system aa′‐dibromo‐p‐xylene(DBX) / CuBr/2,2′‐bipyridine(bipy). The precursor bromo‐terminated polymers were subsequently functionalized with fullerene C₆₀ using CuBr/bipy as the catalyst system under microwave irradiation (MI). The telechelic C₆₀ end‐capped products were characterized by gel permeation chromatography (GPC), UV‐vis, FT‐IR, TGA, DSC, ¹H NMR, and ¹³C NMR. The results showed that microwave irradiation could significantly increase the rate of fullerenation reaction, and the physical properties and structure of the C₆₀ end‐capped polymers are not modified by the use of the microwave. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 828–834, 2006