Synthesis and thermal behavior of poly(methyl methacrylate)/Maghnia bentonite nanocomposite prepared at room temperature via in situ polymerization initiated by a new Ni(II)α‐benzoinoxime complex

Poly(methyl methacrylate) (PMMA) and poly(methyl methacrylate)/clay nanocomposite (PMMA/OBT) were successfully prepared in dioxan at room temperature via in situ radical polymerization initiated by a new Ni(II)α‐ Benzoinoxime complex as a single component in presence of 3% by weight of an organically modified bentonite (OBT) (originated from Maghnia, Algeria) and characterized by FTIR, ¹H‐NMR and viscometry. Mainly intercalated and partially exfoliated PMMA/OBT nanocomposite was elaborated and evidenced by X‐Ray diffraction (XRD) and transmission electron microscopy (TEM). The intrinsic viscosity of PMMA/OBT nanocomposite is much higher than the one of pure PMMA prepared under the same conditions. Differential scanning calorimetry (DSC) displayed an increase of 10°C in the glass transition temperature of the elaborated PMMA/OBT nanocomposite relative to the one of pure PMMA. Moreover, the TGA analysis confirms a significant improvement of the thermal stability of PMMA/OBT nanocomposite compared to virgin PMMA: the onset degradation temperature of the nanocomposite, carried out under nitrogen atmosphere, increased by more than 45°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymerization of methyl methacrylate at high temperature with 1‐butanethiol as chain transfer agent

The free‐radical polymerization of methyl methacrylate (MMA) at high temperature (120 to 180°C) has been studied in the presence of di‐tertiobutyle peroxide as an initiator and 1‐butanethiol as a chain transfer agent. No solvent was used, and the polymerization was run to high monomer conversion. Based on the experimental data collected with a dilatometric reactor, the features of the reaction have been pointed out. Working at high temperature with a chain transfer agent proved efficient to reduce the intensity of the gel effect and control the molecular weight obtained. At a temperature up to 170°C, however, the burn‐out of the initiator limits the final conversion, and the increase of the polymerization rate during the gel effect has been more difficult to detect and quantify. An empirical expression of the termination rate constant has been adopted to describe the autoacceleration and predict the conversion versus time curves and the average molecular weight of the polymer obtained. The mathematical model includes two adjustable parameters that have been determined as a function of the temperature and the initial concentration of the chain transfer agent. The agreement between the predicted and experimental data on conversion and molecular weight was good, while the polydispersity index was often underestimated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1589–1599, 1999     

Microemulsion polymerization of methyl methacrylate initiated with γ ray

Polymerization of methyl methacrylate was studied in an oil and water microemulsion stabilized with styrene 12-butinoyloxy-9-octadecenoic acid. During the polymerization the size change of the monomer-swollen particles with conversion was measured with photon correlation spectroscopy, and the hydrodynamic diameter of the final polymer latex was about 50 nm. The polymerization kinetics in this microemulsion were also investigated. The apparent plateau of the polymerization rate was observed at a low dose rate and high emulsifier content. The mechanism leading to this plateau was discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2621–2626, 1999     

Polymerization of methyl methacrylate catalyzed by macromolecule–copper (II) complex in sodium sulfite aqueous system

Vinyl polymerization initiated by a copper complex immobilized on a novel polymer and characterization has been studied. Monomer, 4‐aldehyde‐3‐hydroxy phenyl acrylate (Ahpa), and its homopolymer, poly(4‐aldehyde‐3‐hydroxy phenyl acrylate) (PAhpa), were synthesized and characterized using IR, elemental analysis, ¹H NMR, TOF MS, etc. The side chain of the polymer can further coordinate with transition metal ions. Its polymeric Cu(II) complex in Na₂SO₃ system is proved to be another useful catalyst in polymerization of methyl methacrylate (MMA) at room temperature. The obtained poly(methyl methacrylate) (PMMA) is similar to those determined by conventional free radical polymerization at the same conditions. Moreover, the catalytic mechanism studied was a “Coordination Hydrogen‐Transfer” process, which is different from that of CuCl₂/Na₂SO₃ system, but analogous with that of PVAm‐Cu(II)/Na₂SO₃ (PVAm = polyvinylamine) system, was speculated and testified. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1285–1290, 2007     

Photo‐Induced atom transfer radical polymerization with nanosized α‐Fe2O3 as photoinitiator

Photo‐induced atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was achieved in poly(ethylene glycol)‐400 with nanosized α‐Fe₂O₃ as photoinitiator. Well‐defined poly(methyl methacrylate) (PMMA) was synthesized in conjunction with ethyl 2‐bromoisobutyrate (EBiB) as ATRP initiator and FeCl₃·6H₂O/Triphenylphosphine (PPh₃) as complex catalyst. The photo‐induced polymerization of MMA proceeded in a controlled/living fashion. The polymerization followed first‐order kinetics. The obtained PMMA had moderately controlled number‐average molecular weights in accordance with the theoretical number‐average molecular weights, as well as narrow molecular weight distributions (M_w/M_n). In addition, the polymerization could be well controlled by periodic light‐on–off processes. The resulting PMMA was characterized by ¹H nuclear magnetic resonance and gel permeation chromatography. The brominated PMMA was used further as macroinitiator in the chain‐extension with MMA to verify the living nature of photo‐induced ATRP of MMA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42389.     

Copolymerization of methyl methacrylate with 4‐vinylpyridine initiated by a novel Ni(II)α‐Benzoinoxime complex

Copolymerizations of methyl methacrylate (MMA) with 4‐vinylpyridine (4VP) were performed from different monomer feed ratios in 1,4‐dioxan at 30°C under free radical initiation experimental conditions, using Ni(II)α‐Benzoinoxime complex as initiator. The obtained copolymers (PMMA4VP) were examined by FTIR and ¹H NMR spectroscopies. The composition of these copolymers was calculated, using ¹H NMR spectra and elemental analysis. Monomer reactivity ratios were estimated from Fineman–Ross (FR, r_m = 0.550, r_v = 1.165) and Kelen–Tudos (KT, r_m = 0.559, r_v = 1.286) linearization methods, as well as nonlinear error in variables model (EVM) method using the RREVM computer program (RREVM, r_m = 0.559, r_v = 1.264). These values suggest that MMA‐4VP pair copolymerizes randomly. ¹H NMR spectra provide information about the stereochemistry of the copolymers in terms of sequence distributions and configurations. These results showed that the age of the Ni complex has an impact not only on its activity towards polymerization reactions but also on the features of the corresponding copolymers, whereas the chemical composition was insensitive to this prominent factor. The mechanism of MMA‐4VP copolymerization is consistent with a radical process as supported by microstructure and molecular weight distribution studies. Thermal behaviours of these copolymers were investigated by differential scanning calorimetry and thermogravimetric analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Polymerization of methyl methacrylate with Ni(acac)2–methylaluminoxane catalyst

Polymerization of methyl methacrylate (MMA) with nickel(II) acetylacetonate [Ni(acac)₂] in combination with methylaluminoxane (MAO) was investigated. Ni(acac)₂ was found to be an effective catalyst for the polymerization of MMA. From a kinetic study of the polymerization of MMA with the Ni(acac)₂–MAO catalyst, the overall activation energy was estimated to be 15 kJmol⁻¹. The polymerization rate (R_p) was expressed as follows: R_p = k [MMA]^1.0[Ni(acac)₂–MAO]^0.6 (the MAO/Ni mole ratio was kept constant). The mechanism for the polymerization of vinyl monomers with the Ni(acac)₂–MAO catalyst is discussed. © 2000 Society of Chemical Industry     

Synthesis and thermal properties of poly(methyl methacrylate)‐poly(L‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer

Poly(methyl methacrylate)‐poly(L ‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer was prepared using atom transfer radical polymerization (ATRP). The structure and properties of the copolymer were analyzed using infrared spectroscopy, gel permeation chromatography, nuclear magnetic resonance (¹H‐NMR, ¹³C‐NMR), thermogravimetry, and differential scanning calorimetry. The kinetic plot for the ATRP of methyl methacrylate using poly(L ‐lactic acid) (PLLA) as the initiator shows that the reaction time increases linearly with ln[M]₀/[M]. The results indicate that it is possible to achieve grafted chains with well‐defined molecular weights, and block copolymers with narrowed molecular weight distributions. The thermal stability of PLLA is improved by copolymerization. A new wash‐extraction method for removing copper from the ATRP has also exhibits satisfactory results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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(I) bromide coordinated by the ionic liquid 1‐[(diethyl amine)amine]ethyl‐3‐methyl imidazolium chloride to catalyze the atom transfer radical polymerization of methyl methacrylate in 1‐allyl‐3‐methyl imidazolium chloride

A coordinating ionic liquid (IL), 1‐[(diethyl amine)amine]ethyl‐3‐methyl imidazolium chloride ([N₃MIM]Cl), was prepared as an alternative to a simple organic ligand to coordinate to copper(I) bromide (CuBr). We, thereby, obtained a novel catalyst for atom transfer radical polymerization (ATRP) reactions. This catalyst was applied to the ATRP of methyl methacrylate in the IL 1‐allyl‐3‐methyl imidazolium chloride ([AMIM]Cl). The chemical structures of the ILs obtained were confirmed by Fourier transform infrared spectroscopy, mass spectrometry, and ¹H‐NMR analyses. The coordination ability of [N₃MIM]Cl was assessed by cyclic voltammetry, and the redox potential of [N₃MIM]Cl–CuBr was ?0.507 V. The [N₃MIM]Cl–CuBr complex was expected to be a markedly more active catalyst than the amine DETA–CuBr complex. The coordination mode toward CuBr was also examined. The [N₃MIM]Cl–CuBr catalyst system showed good controllability in the aforementioned ATRP reaction in [AMIM]Cl. The Cu catalyst was easily separated from the obtained polymer with the coordinating IL as a ligand. Consequently, the coordinating IL overcame the shortcomings of traditional organic ligands, such as poor compatibility with IL media and poor separation of the catalyst from the polymer; this makes it highly promising for applications in the ATRP field. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45484.     

Synthesis and characterization of polyrotaxanes comprising α‐cyclodextrins and poly(ε‐caprolactone) end‐capped with poly(butyl methacrylate)s

Biodegradable polyrotaxane‐based triblock copolymers were synthesized via the bulk atom transfer radical polymerization (ATRP) of n‐butyl methacrylate (BMA) initiated with polypseudo‐rotaxanes (PPRs) built from a distal 2‐bromoisobutyryl end‐capped poly(ε‐caprolactone) (Br‐PCL‐Br) with α‐cyclodextrins (α‐CDs) in the presence of Cu(I)Br/N,N,N′,N″,N″‐pentamethyldiethylenetriamine at 45 ºC. The structure was characterized in detail by means of ¹H NMR, gel permeation chromatography, wide‐angle X‐ray diffraction, DSC and TGA. When the feed molar ratio of BMA to Br‐PCL‐Br was changed from 128 to 300, the degree of polymerization of PBMA blocks attached to two ends of the PPRs was in the range 382 ? 803. Although about a tenth of the added α‐CDs were still threaded onto the PCL chain after the ATRP process, the movable α‐CDs made a marked contribution to the mechanical strength enhancement, blood anticoagulation activity and protein adsorption repellency of the resulting copolymers. Meanwhile, they could also protect the copolymers from the attack of H₂O and Lipase AK Amano molecules, exhibiting a lower mass loss as evidenced in hydrolytic and enzymatic degradation experiments. © 2013 Society of Chemical Industry     

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     

Influence of γ‐irradiation on poly(methyl methacrylate)

Poly(methyl methacrylate) (PMMA) was γ‐irradiated (5–20 kGy) by a ¹³⁷Cs source at room temperature in air. The changes in the molecular structure attributed to γ‐irradiation were studied by mechanical testing (flexure and hardness), size‐exclusion chromatography, differential scanning calorimetry, thermal gravimetric analysis, and both Fourier transform infrared and solution ¹³C‐NMR spectroscopy. Scanning electron microscopy was used to investigate the influence of the dose of γ rays on the fracture behavior of PMMA. The experimental results confirm that the PMMA degradation process involves chain scission. It was also observed that PMMA presents a brittle fracture mechanism and modifications in the color, becoming yellowish. The mechanical property curves show a similar pattern when the γ‐radiation dose increases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 886–895, 2002     

Novel poly(methyl methacrylate)‐block‐polyurethane‐block‐poly(methyl methacrylate) tri‐block copolymers through atom transfer radical polymerization

Poly(methyl methacrylate)‐block‐polyurethane‐block‐poly(methyl methacrylate) tri‐block copolymers have been synthesized successfully through atom transfer radical polymerization of methyl methacrylate using telechelic bromo‐terminated polyurethane/CuBr/N,N,N,N″,N″‐pentamethyldiethylenetriamine initiating system. As the time increases, the number‐average molecular weight increases linearly from 6400 to 37,000. This shows that the poly methyl methacrylate blocks were attached to polyurethane block. As the polymerization time increases, both conversion and molecular weight increased and the molecular weight increases linearly with increasing conversion. These results indicate that the formation of the tri‐block copolymers was through atom transfer radical polymerization mechanism. Proton nuclear magnetic resonance spectral results of the triblock copolymers show that the molar ratio between polyurethane and poly (methyl methacrylate) blocks is in the range of 1 : 16.3 to 1 : 449.4. Differential scanning calorimetry results show T_g of the soft segment at ?35°C and T_g of the hard segment at 75°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of Poly(acrylamide-maleic Acid) Resin by Template Polymerization and Its Use for Adsorption of Co(II) and Ni(II)

Poly(acrylamide-maleic acid) resin P(AAm-MA) was prepared by template polymerization. Polyacrylamide PAAm was used as a template for the polymerization of MA in an aqueous solution using gamma rays as the initiator. The effects on the capacity of P(AAm-MA), such as concentration of maleic acid and amount of template polymer, were investigated. P(AAm-MA) has been utilized as an adsorbent for the removal of Co(II) and Ni(II) ions from an aqueous solution. The effects of time of equilibrium, pH, temperatures, and dosage of the adsorbent on the removal of Co(II) and Ni(II) ions have been studied. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm models. The equilibrium process was described well by the Langmuir isotherm model.     

Polymerization of methyl methacrylate with a thermal iniferter: Diethyl 2,3‐dicyano‐2,3‐di(p‐tolyl)succinate

A hexa‐substituted ethane type compound, diethyl‐2,3‐dicyano‐2,3‐di(p‐tolyl)succinate (DCDTS), was successfully synthesized and used for initiation of methyl methacrylate (MMA) polymerization. The reaction demonstrated the characteristics of a “living” polymerization; i.e., both the yield and the molecular weight of the resulting polymers increased linearly with increasing reaction time, the molecular‐weight distribution of PMMA obtained was ～1.60 and almost unaffected by the conversion, and the resultant polymer can be chain extended by adding fresh MMA. End group analysis of the resultant PMMA confirmed that DCDTS behaves as a thermal iniferter for MMA polymerization. A block copolymer was prepared from the resultant PMMA, which contains a hexa‐substituted C? C bond functional end group. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2566–2572, 2001     

Synthesis of well‐defined polystyrene‐graft‐poly(methyl methacrylate)

A well‐defined graft copolymer, polystyrene‐graft‐poly(methyl methacrylate), was synthesized in two steps. In the first step, styrene and p‐vinyl benzene sulfonyl chloride were copolymerized via reversible addition–fragmentation chain transfer polymerization (RAFT) in benzene at 60 °C with 2‐(ethoxycarbonyl)prop‐2‐yl dithiobenzoate as a chain transfer agent and 2,2′‐azobis(isobutyronitrile) as an initiator. In the second step, poly[styrene‐co‐p‐(vinyl benzene sulfonyl chloride)] was used as a macroinitiator for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in toluene at 80 °C with CuCl as a catalyst and 2,2′‐bipyridine as a ligand. With sulfonyl chloride groups as the initiating sites for the ATRP of MMA, high initiation efficiencies were obtained. Copyright © 2006 Society of Chemical Industry     

Microcomposites of Poly(ε‐caprolactone) and Poly(methyl methacrylate) Prepared by Suspension Polymerization in the Presence of Poly(ε‐caprolactone) Macromonomer

Poly(methyl methacrylate)‐poly(ε‐caprolactone) (PMMA/PCL) microparticles were synthesized by suspension polymerization of methyl methacrylate in the presence of PCL. The incorporation of a small amount of a macromonomer, methacryloyl‐terminated PCL (M‐PCL), into the reaction mixture, led to the formation of grafted systems, namely PMMA‐g‐PCL/PCL. The synthesis of the macromonomer and its characterization by nuclear magnetic spectroscopy (¹H NMR) is described. The role of M‐PCL as an effective compatibilizing agent in the composite was investigated. PMMA/PCL and PMMA‐g‐PCL/PCL composites were fully characterized by ¹H NMR, gel permeation chromatography (GPC) and thermal analysis, including thermogravimetric analysis (TGA), conventional differential scanning calorimetry (DSC), modulated DSC (MDSC) and dynamic mechanical thermal analysis (DMTA). Finally, the morphology of the prepared systems was investigated by scanning electron microscopy (SEM). The addition of compatibilizing agent led the formation of a more homogeneous microcomposite with improved mechanical properties.

SEM picture of PMMA‐g‐PCL/PCL composite surface.     

Co(acac)2‐Mediated Radical Polymerization of Acrylonitrile: Control Over Molecular Weights and Copolymerization With Methyl Methacrylate

The cobalt‐mediated radical polymerization of acrylonitrile in DMSO using cobalt (II) acetylacetonate [Co(acac)₂] as mediator is studied. Both the evolution of molecular weight and conversion over time under various conditions are monitored. Molecular weights increase sharply at the beginning of the reaction and subsequently grow linearly with conversion. No branching of the polymer is observed by ¹³C NMR. By a careful design of the reaction parameters, number‐average molecular weights >1.2 · 10⁵ g · mol^?1 with a PDI around 2.4 together with conversions of up to 90% within 24 h are achieved. The copolymerization parameters of acrylonitrile with methyl methacrylate in DMSO at 30 °C are determined using the Kelen‐Tüdõs approach giving r_AN = 0.33, r_MMA = 0.71.

     

Free‐radical copolymerization of [(4‐isopropyl phenyl) oxycarbonyl] methyl methacrylate with acrylonitrile and methyl methacrylate

The present investigation has been achieved in accordance with the Diels–Alder reaction (1,4 cycloaddition) to produce a new halogenated bicyclic adduct. ortho‐Bromoallylbenzoate is a new dienophile that was prepared in a pure form, and its structure was confirmed. The Diels–Alder syntheses of hexachlorocyclopentadiene and the new dienophile were studied to determine the optimum condensation reaction conditions under a temperature range of 90–160°C, reaction times of 1–8 h, and molar diene/dienophile ratios from 1:1 to 5:1 as a consequence. The optimum conditions reached were a temperature of 140°C, an initial diene/dienophile molar ratio of 3:1, and a duration time of 6 h. The maximum stoichometric yield under these optimum conditions (82.5%) was obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2331–2338, 2003