Polymerization Of N-butyl Methacrylate Research Articles

The effects of catalyst and deactivator species in atom transfer radical polymerization of n-butyl methacrylate

Atom transfer radical polymerization (ATRP) of n-butyl methacrylate (n-BMA) was performed using CuIBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) as catalyst and tosyl chloride (TsCl) as initiator, and different poly(n-butyl methacrylate) samples were prepared by changing the ratios of monomer/initiator and monomer/catalyst. Comparison was made with the data of another ATRP system with 4,4′-di(5-nonanyl)-2,2′-bipyridine (dNbpy) ligand (n-BMA/CuIBr/dNbpy/TsCl). 1H NMR spectroscopy was used successfully to study monomer conversion during polymerization. For lower degree of polymerization (DP) ≤ 200, the corresponding products displayed narrow molecular weight distribution (D ≤ 1.1). Number average molecular weights (Mn) obtained by gel permeation chromatography (GPC) were higher than those calculated (Mn,theory), while in products with higher degree of polymerization (DP = 300), the Mn,theory surpassed Mn,GPC and molecular weight distribution enhanced (D ≤ 1.25). UV–visible spectroscopy was employed to study the probable coordination of monomer to copper bromide and/or ligand. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used for characterization of prepared poly(n-butyl methacrylate)s. Cyclic voltammetry (CV) for CuII/CuI redox couple was performed in solvent mixtures of isobutyl butyrate (saturated form of n-butyl methacrylate) and acetonitrile having different volume fractions (acetonitrile/butyl isobutyrate: 100/0, 80/20, 60/40, 40/60 and 20/80). By introducing moderately nonpolar butyl isobutyrate to polar aprotic acetonitrile, peak-to-peak separation increased. This implied slow electron transfer (lower KET in presence of monomer) that adjusted KATRP.

Termination Kinetics of Surface-Initiated Radical Polymerization Measured by Time-Resolved ESR Spectroscopy after Laser-Pulse Initiation

The single-pulse–pulsed-laser polymerization–electron spin resonance (SP-PLP-ESR) method was used to study the termination reaction in polymerization of n-butyl methacrylate (n-BMA) from silica nanoparticles. The polymerization from the surface was initiated by the surface-attached photoinitiator 2,2-dimethoxy-2-phenyl-1-(2-(2-(trimethoxysilyl)ethyl)phenyl)ethane-1-one (DMPTS). The obtained termination rate coefficient at 335 K of kt = (5.4 ± 0.7) × 106 L mol–1 s–1, which could unambiguously be assigned to the termination reaction between two surface-attached macroradicals, is about 2 orders of magnitude smaller than the value found in homogeneous n-BMA polymerization. Surprisingly, no chain-length dependence of the termination rate coefficient could be observed. This fact and temperature-dependent studies of kt, which yield an activation energy that is in perfect agreement with the activation energy of propagation of n-BMA, indicate that the termination between surface-attached macroradicals proceeds under reaction diffusion control, as their translational diffusion is suppressed.

Semi-continuous Heterophase Polymerization of n-Butyl Methacrylate: Effect of Monomer Feeding Rate

The effect of monomer feeding rate on particle size, molar masses, glass transition and tacticity of poly(n-butyl methacrylate) (PBMA) nanoparticles synthesized by semi-continuous heterophase polymerization under monomer-starved conditions is reported. Three feed rates were examined. Highly monomer-starved conditions at the two slower addition rates were confirmed by the low amount of residual monomer throughout the reaction and by the fact that the instantaneous polymerization and feeding rates became similar at later stages of the reaction. Under these conditions, polymer particles in the nanometer range (30 to 35 nm) were obtained. Glass transition temperatures are substantially higher than those reported for commercial PBMA. Polymers tacticity was determined by 13C-NMR spectroscopy. NMR measurements confirm that the syndiotactic content of the PBMA synthesized here is larger than those of the commercial ones made by free-radical polymerization. Molar masses are much lower than those expected from termination by chain transfer to monomer, which is the typical termination mechanism in microemulsion polymerization.

Synthesis, Characterization and Application of a Multi-Site Phase Transfer Catalyst in Radical Polymerization of n-Butyl Methacrylate—A Kinetic Study

The multi-site phase transfer catalyzed radical polymerization of n-butyl methacrylate (n-BMA) using newly synthesized and characterized 1,1,2,2-tetramethyl-1-benzyl-2-n-propylethylene-1,2-diammonium bromide chloride (TMBPEDBC) as a multi-site phase transfer catalyst was investigated in an aqueous-organic two-phase system at 60 ± 1°C under nitrogen circumstances. The kinetics and effects of various operating variables (monomer, initiator, catalyst, temperature, acid, and ionic strength) on the rate of polymerization (Rp) were examined in detail. The order with respect to monomer, initiator and multi-site phase transfer catalyst was found to be 0.50. A suitable kinetic reaction scheme has been proposed to account for experimental observations, and its significance is discussed.

Homopolymerization of n‐butyl methacrylate using bis(salicylaldiminate)copper(II)/ methylaluminoxane catalysts

AbstractPolymerization catalysts based on copper precursors appear particularly interesting due to the low metal cost, limited toxicity and modest sensitivity to deactivation by polar species. To date, α‐olefin and polar monomer coordination polymerization catalysed using copper catalysts has been scarcely investigated, and a good part of the literature is represented by patents. Here this research has been expanded to the study of the performances of bis(salicylaldiminate)copper(II)/methylaluminoxane (MAO) catalysts in the polymerization of n‐butyl methacrylate. The study of the catalytic activity of bis(salicylaldiminate)copper(II)/MAO systems in n‐butyl methacrylate polymerization was focused on the relationship between the catalytic behaviour and the main reaction conditions and ligand structures. The electronic and steric characteristics of the chelate ligands play an important role in the catalytic performances. The presence of electron‐withdrawing nitro groups on the chelate ligands increased the catalytic activity which reached 36 kgpolymer mol−1 h−1, the highest value up to now reported for copper systems in methacrylic or acrylic monomer polymerization. These performances were ascribed to copper catalysts activated by MAO: without copper precursor, working in the presence of MAO and free salicylaldimine ligand, complete inactivity was ascertained. Copyright © 2010 Society of Chemical Industry

MULTI-SITE PHASE TRANSFER CATALYZED RADICAL POLYMERIZATION OF n-BUTYL METHACRYLATE: A KINETIC STUDY

The kinetics and mechanism of radical polymerization of n-butyl methacrylate (n-BMA) using potassium peroxydisulfate (PDS) as a water-soluble initiator in the presence of 1,4-bis(tributyl methyl ammonium) benzene dichloride (TBMABDC) as a multi-site phase transfer catalyst (MPTC) were studied. The polymerization reactions were carried out under oxygen-free, unstirred conditions at a constant temperature of 60° ± 1°C in cyclohexane-water two-phase systems. The dependence of rate of polymerization (Rp) on concentrations of monomer, initiator, and catalyst, volume fraction of aqueous phase, solvent polarity, and temperature was determined. The reaction order with respect to monomer, initiator, and multi-site phase transfer catalyst was found to be 0.50, 1.0, and 0.52 respectively. Based on the experimental results, an appropriate reaction mechanism has been proposed and its significance discussed. The prepared polymer was characterized with spectral analysis.

Surfactant-Free, Controlled/Living Radical Emulsion Polymerization in Batch Conditions Using a Low Molar Mass, Surface-Active Reversible Addition-Fragmentation Chain-Transfer (RAFT) Agent

The purpose of this paper was to study the application of a surface-active trithiocarbonate RAFT agent, the 2-(dodecylthiocarbonothioylthio)-2-methylpropanoic acid, sodium salt (TTCA) in surfactant-free, ab initio, batch emulsion polymerization. Because of the highly water-soluble character of the leaving group favoring exit from the micelles or the particles over reinitiation, the polymerization of styrene was completely inhibited. In contrast, the polymerization of n-butyl methacrylate was fast and led to small, stable particles, demonstrating the good stabilizing efficiency of TTCA. However, the control over molar mass was not effective, as homopolymers with high molar mass were formed. This was related to the inappropriate leaving/initiating group and low chain transfer constant of the RAFT agent in the free-radical polymerization of methacrylic esters and was also observed in bulk. This poor efficiency was overcome by copolymerizing n-butyl methacrylate with a low percentage of styrene or n-butyl acrylate. In this case, the bulk copolymerization led to controlled copolymers with predicted molar mass and narrow molar mass distribution and the chain transfer efficiency was similarly high in surfactant-free emulsion polymerization. The good colloidal characteristics of the latexes with the stabilizing group attached at the chain-end were maintained, leading to autostabilized latexes with small particle diameter, below 150 nm. This work is the first example of the direct and efficient use of a surface-active, low molar mass, RAFT agent in emulsifier-free, batch emulsion polymerization, leading simultaneously to a good control over molar mass and narrow molar mass distribution, together with good colloidal properties.

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.

Effects of Agitation on Oxygen Inhibition, Particle Nucleation, Reaction Rates, and Molecular Weights in Emulsion Polymerization of n-Butyl Methacrylate

Oxygen-free conditions are required during emulsion polymerization reactions to eliminate the inhibition effect of oxygen on the free-radical mechanism of polymerization. Results of a kinetic study of the emulsion polymerization of n-butyl methacrylate using a 1-dm3 reaction calorimeter indicate that oxygen, even in concentrations as low as 1 ppm, not only prolongs the induction period that precedes the chain propagation but also influences the particle nucleation and molecular weights. Agitation promotes the transfer of residual oxygen from the reactor headspace into the emulsion and, therefore, has an effect on the particle nucleation step and other reaction events that follow.

Studies of higher temperature polymerization ofn-butyl methacrylate andn-butyl acrylate

Free-radical acrylic polymerizations of n-butyl methacrylate and n-butyl acrylate at temperatures above 120°C show significant departure from classic free-radical kinetics. An extended model of depropagation, where the equilibrium monomer concentration varies with temperature and polymer content, is postulated and shown to adequately explain the data for n-butyl methacrylate. Intramolecular chain transfer and scission is postulated to explain the apparent reduction in molecular weight and rate of polymerization seen in n-butyl acrylate polymerization, with supporting experimental evidence found via electrospray-ionization mass spectrometry.

Influence of the swelling state of seed polymer particles with monomer on the morphology of micron-sized monodispersed composite polymer particles produced by seeded polymerization utilizing the dynamic swelling method

Micron-sized mono-dispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles (PS/PBMA=2/1 by weight) having a heterogeneous structure in which many fine PBMA domains dispersed in a PS matrix near the particle surface were produced by seeded polymerization of n-butyl methacrylate (BMA) of which almost all had been absorbed by 1.8 µm-sized monodispersed PS seed particles utilizing the dynamic swelling method. The morphology was varied by changing the PS/BMA ratio and polymerization temperature. It was concluded that the swelling state of 2 µm-sized BMA-swollen PS particles in the seeded polymerization process is one of the important factors to control the morphology of the composite particles.

Application of a calorimetric method in radiation-induced polymerization—III: Determination of propagation and termination rate constants for n-butyl methacrylate

A study on the polymerization of n-butyl methacrylate has been performed using 60COγ-rays. The kinetics were followed by a calorimetric method already used with methyl- and ethyl-methacrylate. In this case also, the rate of polymerization was found to be proportional to (dose rate) 1 2 over wide ranges of dose rate and temperature. Rate constants for propagation and termination steps have been determined; the results agree with those for the other monomers and with literature data.

Polymerization of esters of methacrylic acid. Part I.—the polymerization of n-butyl methacrylate

Polymerization of esters of methacrylic acid. Part I.—the polymerization of n-butyl methacrylate