Kinetic study of RuIII‐catalyzed polymerization of methylmethacrylate initiated with n‐butylamine in the presence of carbon tetrachloride by a charge‐transfer mechanism

Ruthenium trichloride (RuCl₃ or Ru^III) catalyzed polymerization of methylmethacrylate (MMA) initiated with n‐butylamine (BA) in the presence of carbon tetrachloride (CCl₄) by a charge‐transfer mechanism has been investigated in a dimethylsulfoxide (DMSO) medium by employing a dilatometric technique at 60°C. The rate of polymerization (R_p) has been obtained under the conditions [CCl₄]/[BA] ? 1 and [CCl₄]/[BA] ? 1. The kinetic data indicate the possible participation of the charge‐transfer complex formed between the amine–Ru^III complex and CCl₄ in the polymerization of MMA. In the absence of either CCl₄ or BA, no polymerization of MMA is observed under the present experimental conditions. The rate of polymerization is inhibited by hydroquinone, suggesting a free‐radical initiation. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 70–77, 2011     

Polymerization of methyl methacrylate by charge-transfer mechanism with aliphatic primary amines and carbon tetrachloride

Polymerization of methyl methacrylate (MMA) with aliphatic primary amines and carbon tetrachloride has been investigated in th dimethylsulfoxide medium by employing a dilatometric technique at 60°C. The rate of polymerization (R_p) has been evaluated under the conditions, [CCl₄]/[amine] < 1 and > 1. The kinetic data indicate possible participation of the charge transfer complexes formed between the amine + CCl₄ and the amine + MMA in the polymerization of MMA. In the absence of CCl₄ or amine, no polymerization of MMA was observed under the present experimental conditions. The polymerization of MMA was inhibited by hydroquinone, indicating a free radical initiation. The energy of activation varied from 32 to 58 kJ mol^?1.     

Polymerization of methyl methacrylate with aminoalcohols and carbon tetrachloride initiated by charge-transfer mechanism

Polymerization of methylmethacrylate (MMA) with aminoalcohols, namely ethanolamine (EA), diethanolamine (DEA) and triethanolamine (TEA) in the presence of carbontetrachloride (CCl₄) has been investigated in the dimethylsulfoxide (DMSO) medium by employing a dilatometric technique. The rate of polymerization (R _p) has been evaluated under the conditions and > 1. The kinetic data reveal the possible participation of a charge-transfer complex in the polymerization reaction. In the absence of either CCl₄ or amine, no polymerization of MMA was observed under the present experimental conditions. The polymerization of MMA was inhibited by hydroquinone, indicating a free radical initiation.     

Polymerization of Methyl Methacrylate by Charge-Transfer Mechanism with Amines and Carbon Tetrachloride

The charge-transfer complex formed between an amine and carbon tetrachloride can initiate the polymerization of vinyl monomers in a nonaqueous solvent such as dimethylsulfoxide. Here we use cyclopentylamine (CPA) and heptylamine (HA) as the donor compounds for charge-transfer initiation of the polymerization of methl methacrylate (MMA). The rate of polymerization R_p = k[MMA]¹ [amine]^0.5 [CCl₄]^0.5 when [CCl₄] [amine] ≤ 1; when [CCl₄] [amine] < 1, R_p becomes independent of [CCl₄] and R_p = k[MMA]^1.5 [amine]^0.5. The average constant at 60°C for the polymerization of MMA in terms of monomer were (1.66 ± 0.03) × 10^?5 and (1.46 ± 0.04) × 10^?5 s^?1 with CPA and HA, respectively, when [CCl₄] [amine] ≤ 1, and (1.16 ± 0.04) × 10^?5 and (1.39 ± 0.08) × 10^?1 L/mol·s when [CCl₄]/[amine] < 1.     

Polymerization of methyl methacrylate by charge-transfer complex using n-butyl amine and carbon tetrachloride in dimethylsulphoxide

The charge-transfer complex formed by the interaction of an aliphatic amine, such as n-butylamine (nBA), and carbon tetrachloride (CCl₄) in dimethylsulphoxide (DMSO) initiates polymerization of methyl methacrylate (MMA) at 30°. The rate of polymerization is given by R_p = k[MMA]^0.83 [nBA]^0.5 [CCl₄]^0.5 when [CCl₄]/[nBA] is ? 1. When [CCl₄]/[nBA] > 1, R_p is independent of [CCl₄] and R_p = k[MMA]^1.46 [nBA]^0.5. The average rate constants are (1.42 ± 0.05) × 10^?6 1 mol^?1 sec^?1 in terms of MMA and (2.20 ± 0.06) × 10^?6 sec^?1 at 30° for higher and lower concentration of carbon tetrachloride respectively. A charge-transfer mechanism for polymerization is suggested.     

Polymerization of methyl methacrylate by a charge transfer mechanism with urea and iron (III) complex

Methyl methacrylate (MMA) can be polymerized by a charge transfer complex formed by the interaction of urea, methyl methacrylate, and carbon tetrachloride (CCl₄) in a nonaqueous solvent like dimethylsulfoxide (DMSO). The rate of polymerization can be accelerated by Lewis acids like Fe³⁺. This article reports the polymerization of MMA initiated by urea and CCl₄ and accelerated with hexakisdimethylsulfoxide iron (III) perchlorate, [Fe(DMSO)₆](ClO₄)₃, and A at 60°C. Definite induction periods were observed for the polymerization reaction initiated by urea and CCl₄ alone, but the induction period completely vanished when the molar ratio of urea to A reached 6:1. The molecular weights of the polymers with 6:1 molar ratio of urea to A were higher than with urea alone. The rate constant for the polymerization of MMA in the presence of [Fe(urea)₆]³⁺ was 1.03 × 10^?5 1 mol^?1 s^?1 at 60°C. The transfer constant for CCl₄ for polymerization with urea alone is 2.43 × 10^?3 at 60°C.     

Polymerization of methyl methacrylate by charge transfer mechanism by melamine and iron(III) complex

Methyl methacrylate (MMA) can be polymerized by the charge-transfer complex formed by the interaction of melamine (MM), MMA and carbon tetrachloride in a non-aqueous solvent like dimethyl sulphoxide (DMSO) or N-N-dimethylformamide. The polymerization can be accelerated by Lewis acids like Fe^3?. This paper reports the polymerization of MMA initiated by MM and CCl₄ and accelerated with hexakis dimethylsulphoxide iron(III) perchlorate [Fe(DMSO)₆] (ClO₄)₃. A, at 60°. Induction periods were observed for the polymerization initiated by MM and CCl₄ alone, but not when the molar ratio of MM to A became 3:1. The molecular weights of the polymers with 3:1 molar ratio of MM to A were higher than with MM alone. The rate constant for the polymerization of MMA in presence of [Fe(MM)₃]³⁺ was 1.4181 × 10^?5 1 mol^?1 sec^?1 at 60°. The transfer constant for CCl₄, in the absence of A, is 4.66 × 10^?3.     

Charge transfer initiation of methylmethacrylate by isopropylamine

Methylmethacrylate (MMA) can be initiated by charge transfer complexes (i) formed by the interaction of aliphatic amines and MMA and (ii) formed by the interaction of aliphatic amines and carbon tetrachloride in a solvent like N-N dimethylformamide (DMF), dimethyl sulphoxide (DMSO) or chloroform. This paper reports the polymerization of MMA by isopropylamine (IPA) in the presence of CCl₄ in DMSO at 30. The rate of polymerization, R_p increases rapidly with CCl₄ up to a concentration of 0.25 mol l^?1 but, for a higher concentration, it is practically independent of the CCl₄ concentration. R_p is proportional to (IPA concentration)^{1 2} and to power of (MMA concentration)^1.30 when [CCl₄] ? [IPA]. The average rate constant, k, is 2.1 × 10^?6 l mol^{· 1} sec^{? 1}.     

Preparation of a copolymer of methyl methacrylate and 2‐(dimethylamino)ethyl methacrylate with pendant 4‐benzyloxy‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy and its initiation of the graft polymerization of styrene by a controlled radical mechanism

The macroinitiator of a copolymer (PMD_BTM) of methyl methacrylate (MMA) and 2‐(dimethylamino)ethyl methacrylate (DAMA) with 4‐benzyloxy‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy (BTEMPO) pendant groups was prepared by the photochemical reaction of tertiary amine groups of the copolymer with benzophenone in the presence of BTEMPO. The radical copolymerization of MMA and DAMA was carried out first with azo‐bis‐isobutyronitrile (AIBN) as an initiator; then, the dimethylamine groups of the copolymer constituted a charge‐transfer complex with benzophenone under UV irradiation, and the methylene of ternary amine and diphenyl methanol radicals were produced. The former was capped by BTEMPO, and the nitroxide (BTEMPO) was attached to the polymeric backbone. The amount of pendant BTEMPO on PMD_BTM was measured by ¹H NMR. PMD_BTM initiated the graft polymerization of styrene via a controlled radical mechanism, and the molecular weight of the PMD‐g‐polystyrene increased with the polymerization time. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 604–612, 2001     

Effect of Rh(III) and Ru(II) complexes in the polymerization of vinyl monomers initiated by charge transfer mechanism

The initiation of polymerization of vinyl monomers such as methyl methacrylate (MMA) and methyl acrylate (MA) by a charge transfer complex formed between n-butylamine(nBA) and carbon tetrachloride (CCl₄) in dimethylsulfoxide (DMSO) at 30°C is slow. The effect of the dimethylsulfoxide complexes of Rh(III) and Ru(II) on the polymerization of MMA and MA in the presence of nBA, and CCl₄ in DMSO has been studied. The rate of polymerization and percent conversion of the MMA and MA at 30°C are evaluated at the critical concentration of the metal complexes. At the critical range of the metal complex concentrations, both R_p, and percent conversion of MMA and MA were found to be highest. However, above and below the critical concentrations, R_p and percent conversion of the monomers were found to decrease. A suitable mechanism for the polymerization has been proposed.     

Stereocontrol in the free‐radical polymerization of methacrylates with fluoroalcohols

The free‐radical polymerization of methyl methacrylate (MMA), ethyl methacrylate (EMA), isopropyl methacrylate (IPMA), and tert‐butyl methacrylate (t‐BuMA) was carried out under various conditions to achieve stereoregulation. In the MMA polymerization, syndiotactic specificity was enhanced by the use of fluoroalcohols, including (CF₃)₃COH as a solvent or an additive. The polymerization of MMA in (CF₃)₃COH at −98 °C achieved the highest syndiotacticity (rr = 93%) for the radical polymerization of methacrylates. Similar effects of fluoroalcohols enhancing syndiotactic specificity were also observed in the polymerization of EMA, whereas the effect was negligible in the IPMA polymerization. In contrast to the polymerizations of MMA and EMA, syndiotactic specificity was decreased by the use of (CF₃)₃COH in the t‐BuMA polymerization. The stereoeffects of fluoroalcohols seemed to be due to the hydrogen‐bonding interaction of the alcohols with monomers and growing species. The interaction was confirmed by NMR measurements. In addition, in the bulk polymerization of MMA at −78 °C, syndiotactic specificity and polymer yield increased even in the presence of a small amount {[(CF₃)₃COH]/[MMA]_o < 1} of (CF₃)₃COH. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4693–4703, 2000     

Vinyl Polymerization. 371. Polymerization of Methyl Methacrylate Initiated by the System of Polyvinylferrocene and Carbon Tetrachloride

The polymerization of vinyl monomers initiated with the system of polyvinylferrocene (PVFc) and carbon tetrachloride (CCl₄) was carried out in dark. Methyl methacrylate (MMA) and acrylonitrile (AN) could be polymerized, while styrene (St) was hardly polymerized under the conditions used. The polymerization proceeded through a free-radical mechanism and was concluded to be initiated by attack of vinyl monomer, having a polarized vinyl group, on the charge-transfer complex of PVFc/CCl₄. In the polymerization of MMA, the initiating ability of PVFc was much larger than that of ferrocene (Fc-H) or poly(ferrocenylmethyl methacrylate) (PFMMA) and was comparable to that of polyferrocenylenemethylene (PFM). The overall activation energy was estimated to be 34.2 kJ/mole.     

Synthesis of well‐defined syndiotactic poly(methyl methacrylate) with low‐temperature atom transfer radical polymerization in fluoroalcohol

The copper‐mediated atom transfer radical polymerization of methyl methacrylate (MMA) in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) was studied to simultaneously control the molecular weight and tacticity. The polymerization using tris[2‐(dimethylamino)ethyl]amine (Me₆TREN) as a ligand was performed even at ?78°C with a number‐average molecular weight (M_n) of 13,400 and a polydispersity (weight‐average molecular weight/number‐average molecular weight) of 1.31, although the measured M_n's were much higher than the theoretical ones. The addition of copper(II) bromide (CuBr₂) apparently affected the early stage of the polymerization; that is, the polymerization could proceed in a controlled manner under the condition of [MMA]₀/[methyl α‐bromoisobutyrate]₀/[CuBr]₀/[CuBr₂]₀/[Me₆TREN]₀ = 200/1/1/0.2/1.2 at ?20°C with an MMA/HFIP ratio of 1/4 (v/v). For the field desorption mass spectrum of Cu^IBr/Me₆TREN in HFIP, there were [Cu(Me₆TREN)Br]⁺ and [Cu(Me₆TREN)OCH(CF₃)₂]⁺, indicating that HFIP should coordinate to the Cu^I/Me₆TREN complex. The syndiotacticity of the obtained poly(methyl methacrylate)s increased with the decreasing polymerization temperature; the racemo content was 84% for ?78°C, 77% for ?30°C, 75% for ?20°C, and 63% for 30°C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1436–1446, 2006     

Cyclodextrins in polymer synthesis: free radical polymerization of cyclodextrin host‐guest complexes of methyl methacrylate or styrene from homogenous aqueous solution

The polymerization of methylated β‐cyclodextrin (m‐β‐CD) 1 : 1 host‐guest compounds of methyl methacrylate (MMA) ( 1 ) or styrene ( 2 ) is described. The polymerization of complexes 1 a and 2 a was carried out in water with potassium peroxodisulfate (K₂S₂O₈)/sodium hydrogensulfite (NaHSO₃) as radical redox initiator at 60°C. Unthreading of m‐β‐CD during the polymerization led to water‐insoluble poly(methyl methacrylate) (PMMA) ( 3 ) and polystyrene ( 4 ). By comparison, analogously prepared polymers from uncomplexed monomers 1 and 2 in ethanol as organic solvent with 2,2′‐azoisobutyronitrile (AIBN) as radical initiator showed significantly lower molecular weights and were obtained in lower yields in all cases. Polymerization of m‐β‐CD complexed MMA in water, initiated with 2,2′‐azobis(N,N ′‐dimethyleneisobutyroamidine) dihydrochloride, occurred much faster than the polymerization of uncomplexed MMA in methanol under similar conditions. Furthermore, it was shown, that the precipitation polymerization of complexed MMA from homogeneous aqueous solution can be described by equations (P_n^–1 ∝ lsqb;Irsqb;^0.5) similar to those for classical polymerization in solution.     

The effect of mixed solvents pyridine–carbon tetrachloride on the radical polymerization of methyl methacrylate

A study was made of the methyl methacrylate (MMA) solution polymerization in CCl₄-pyridine mixtures as well as in net components at 30, 50, and 70°C. The results obtained show that there are no significant deviations from additivity in the overall chain transfer constants that fit the straight line between the values of Cs for CCl₄ and pyridine. It can be concluded that the EDA interaction between CCl₄ and pyridine does not change the sensitivity of each component for chain transfer from propagation PMMA free radical. The pyridine in the system increases the rate of MMA polymerization as a result of the higher rate of initiation.     

Cuso4‐amine redox‐initiated radical polymerization of methyl methacrylate mediated by a CuCl2 complex: Homogeneous reverse ATRP

Kinetic results of CuSO₄/2,2'‐bipyridine(bPy)‐amine redox initiated radical polymerization of methyl methacrylate (MMA) at 70 to 90 °C in dimethylsulfoxide suggest that such initiation is characteristic of a slow rate and a low initiator efficiency, but tertiary amines exhibit a relatively higher rate. UV‐Vis spectroscopy confirms the alpha‐amino functionality of PMMA chains. CuCl₂/bPy successfully mediates the redox‐initiated radical polymerization of MMA with aliphatic tertiary amines in a fashion of slow‐initiated reverse atom transfer radical polymerization (ATRP), i.e. both the initiator efficiency of aliphatic tertiary amines and the average molecular weight of PMMA increase gradually, while the molecular weight distribution remains narrow but become broader with the conversions. As the PMMA chains contain alpha amino and omega C‐Cl moieties, UV‐induced benzophenone‐initiated radical polymerization and Cu^ICl/bPy‐catalyzed ATRP initiated from PMMA lead to block copolymers from terminal functionalities. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2562‐2578     

Syntheses of Some New Group 4 non-Cp Complexes Bearing Schiff-base, Thiophene Diamide Ligands Respectively and Their Catalytic Activities for a-Olefin Polymerization

Totally sixteen new titanium and zirconium non-Cp complexes supported by Schiff-base, or thiophene diamide ligands have been synthesized. The complexes are obtained by the reaction of M(OPr-i)4(M=Ti,Zr) with the corresponding Schiff-base ligand in 1:1 molar ratio in good yield. The thiophene diamide titanium complex has been prepared from trimethylsilyl amine [N,S,N] ligand and TiCl4 in toluene at 120℃. All complexes are well charac-terized by ^1H NMR, IR, MS and elemental analysis. When activated by excess methylaluminoxane (MAO), complexes show moderate catalytic activity for ethylene polymerization, and complex If (R^1=CH3,R^2=Br) exhibits the highest activity for ethylene and styrene polymerization. When the complexes were preactivated by triethylaluminum (TEA), both polymerization activities and syndiotacticity of the polymers were greatly improved.     

Radical polymerization of new functional monomer: Methacryloyl isocyanate containing 4‐chloro‐1‐phenol

New functional monomer methacryloyl isocyanate containing 4‐chloro‐1‐phenol (CPHMAI) was prepared on reaction of methacryloyl isocyanate (MAI) with 4‐chloro‐1‐phenol (CPH) at low temperature and was characterized with IR, ¹H, and ¹³C‐NMR spectra. Radical polymerization of CPHMAI was studied in terms of the rate of polymerization, solvent effect, copolymerization, and thermal properties. The rate of polymerization of CPHMAI has been found to be smaller than that of styrene under the same conditions. Polar solvents such as dimethylsulfoxide (DMSO) and N,N‐dimethyl formamide (DMF) were found to slow the polymerization. Copolymerization of CPHMAI (M₁) with styrene (M₂) in tetrahydrofuran (THF) was studied at 60°C. The monomer reactivity ratio was calculated to be r₁ = 0.49 and r₂ = 0.66 according to the method of Fineman—Ross. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 469–473, 2000     

Controlled/living polymerization of MMA promoted by heterogeneous initiation system (EPN‐X–CuX–bpy)

The polymerization of methyl methacrylate (MMA) promoted by heterogeneous initiation system (ethyl‐2‐halopropionate (EPN‐X)–CuX–2,2′‐bipyridyl (bpy), where X = Br or Cl) is studied in detail. The results show that ethyl‐2‐bromopropionate (EPN‐Br) is an efficient initiator as expected, and that CuCl–bpy, instead of CuBr–bpy, is a better catalyst for the controlled polymerization of MMA. The solvents with a high value of dielectric constant (ε) will lead to fast initiation and narrow molecular weight distribution (MWD). As a result, the controlled, living polymerization of MMA with EPN‐Br–CuCl–bpy can be got in ethyl acetate (EAc) at 100°C and in acetonitrile at 80°C. All results suggest that the initiation reaction is a controlling step in the controlled polymerization of MMA. The relationship between the UV spectra of CuCl–bpy and the performances of the polymerization in EAc or acetonitrile suggest that the formation of bis‐bpy complex, [Cubpy₂]X⁻, will lead to fast initiation and good control of the polymerization. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1255–1263, 1999     

Reverse atom transfer radical solution polymerization of methyl methacrylate under pulsed microwave irradiation

The reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) was successfully carried out under pulsed microwave irradiation (PMI) at 69 °C with N,N‐dimethylformamide as a solvent and with azobisisobutyronitrile (AIBN)/CuBr₂/tetramethylethylenediamine as an initiation system. PMI resulted in a significant increase in the polymerization rate of RATRP. A 10.5% conversion for a polymer with a number‐average molecular weight of 34,500 and a polydispersity index of 1.23 was obtained under PMI with a mean power of 4.5 W in only 52 min, but 103 min was needed under a conventional heating process (CH) to reach a 8.3% conversion under identical conditions. At different [MMA]₀/[AIBN]₀ molar ratios, the apparent rate constant of polymerization under PMI was 1.5–2.3 times larger than that under CH. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3823–3834, 2002