Polymerization Of Methyl Vinyl Ether Research Articles

End‐group modified poly(methyl vinyl ether): Characterization and LCST demixing behavior in water

AbstractA range of hydrophilic poly(methyl vinyl ether) (PMVE) polymers was synthesized by living cationic polymerization of methyl vinyl ether (MVE), having different hydrophilic or hydrophobic chain‐end functionalities. The dissimilar end‐groups were either introduced by end‐capping of the growing polymer chain with LiBH4, methanol, and water or by functional initiation with 2‐bromo‐(3,3‐diethoxy‐propyl)‐2‐methylpropanoate. The synthesized PMVEs were characterized by 1H NMR, size exclusion chromatography, and matrix‐assisted laser desorption ionization time of flight, displaying a narrow polydispersity. Modulated temperature DSC was applied to study the influence of the nature of the end‐groups on the solubility behavior of PMVE in water. Terminal‐modification with a hydroxyl function improves the solubility, whereas a Br‐containing end‐group causes the polymer to be insoluble in water at room temperature; however, the special type III lower critical solution temperature demixing behavior being maintained. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 461–469, 2006

Evaluation of the Potential of [{Me2C(Cp)2}Zr(Me)]+ and [{Me2C(Cp)2}Zr(H)]+ as Single-Site Catalysts for Controlled Methyl Vinyl Ether Polymerizations by Density Functional Calculations

Density functional calculations were carried out on the B3LYP level of theory to study the initiation and propagation steps of polymerization of methyl vinyl ether (MVE) using [Me2C(Cp)2Zr(Me)]+ and [Me2C(Cp)2Zr(H)]+ as catalysts. From the obtained results it is concluded that initiation is possible in general with [Me2C(Cp)2Zr(H)]+ as the catalyst and unlikely to happen with [Me2C(Cp)2Zr(Me)]+. Also with [Me2C(Cp)2Zr(H)]+ active propagation channels were found, which generally render the polymerization possible. However, the range of suitable reaction conditions appears to be so narrow that subtleties, which cannot be treated easily in a computational study, might still prevent polymerization. Furthermore, inactive but not irreversible propagation paths were found, which lead to species that are favored energetically compared to species in active reaction channels. This finding also hints at a successful polymerization to be problematic but not necessarily impossible. Also, the search for a catalyst precursor compoundwhich was located as [Me2C(Cp)2Zr(H)(Ph)]was successful.

Thermosensitive polymer structures based on segmented copolymer networks

Segmented polymer networks with LCST-behavior have been prepared by free radical initiated copolymerization of α,ω-bis-methacrylate terminated poly(methyl vinyl ether) (PMVE) with 2-hydroxy ethyl methacrylate (HEMA) or butyl acrylate (BA). The PMVE bis-macromonomers have been obtained via a semi-continuous process by end-capping the living cationic polymerization of methyl vinyl ether (MVE) with HEMA. The phase separation temperature can be varied by changing the PMVE/comonomer ratio. Incorporation of PMVE-grafts in the hydrogels increases the rate of deswelling and improves the mechanical properties. The application of the segmented networks for thermo-controllable solid phase extraction has been demonstrated by their thermosensitive adsorption behavior of toluene from a water solution.

Controlled cationic polymerization of methyl vinyl ether with a semi-continuous process

A semi-continuous process for the controlled cationic polymerization of methyl vinyl ether (MVE) was developed. The initiating system was a combination of 1,1-diethoxyethane (DEE), trimethyl silyl iodide (TMSI), and ZnI2 as activator. The optimal reaction conditions were a reaction temperature of-5 °C in toluene, an initiator to activator ratio of 5 to 1, and a monomer feed rate of 0.86 mol/h. With these reaction conditions, poly(methyl vinyl ethers) (PMVEs) with molecular weights up to 7500 could be prepared in quantities up to 30 g with narrow molecular weight distributions (MWD<1.2) and still possessing active chain ends which can be end-capped with a nucleophilic terminator.

Cationic macromolecular engineering via furan derivatives

General methodologies for the synthesis of linear and star-block copolymers and functional polymers using furan derivatives are reviewed, based on a study of addition reactions of 2-substituted furans to living polyisobutylene (PIB+). Rapid and quantitative mono-addition of 2-alkyl (and aryl)furans (2-R-Fu), a new class of non-(homo)polymerizable monomers, to PIB+ has been observed in conjunction with TiCl4 as Lewis acid in hexane/CH2Cl2 or CH3Cl 60/40 (v/v) at −80 °C and with BCl3 in CH3Cl at −40 °C, in the presence of proton trap. The resulting stable allylic cation (PIB-Fu+-R) was found to be an efficient initiating species for the polymerization of methyl vinyl ether (MeVE). Using 2,5-bis[1-furanyl)-1-methylethyl]-furan, coupling of living PIB was found to be rapid and quantitative in hexanes(Hex)/CH3Cl 60/40 or 40/60 (v/v) solvent mixtures at −80 °C in conjunction with TiCl4, as well as in CH3Cl at −40 °C with BCl3 as Lewis acid. The kinetics of addition of 2-R-Fu to PIB+ was investigated by UV-vis spectroscopy. Based on these results and those obtained with substituted 1,1-diarylethylenes earlier, the absolute rate constants of ionization (ki), reversible termination (k−i) and propagation (kp) in the polymerization of IB have been determined. By a similar approach the corresponding rate constants have also been determined for the polymerization of styrene.

Cationic Macromolecular Design and Synthesis Using Furan Derivatives

General methodologies for the synthesis of block copolymers and functional polymers using furan derivatives are reported on the basis of a study of addition reactions of 2-substituted furans to living polyisobutylene (PIB+). Rapid and quantitative monoaddition of 2-methylfuran (2-MeFu) and 2-tert-butylfuran (2-tBuFu) to PIB+ has been observed in conjunction with TiCl4 as Lewis acid in hexanes (Hex)/CH2Cl2 or CH3Cl 60/40 v/v at −80 °C and with BCl3 in CH3Cl at −40 °C, in the presence of proton trap. Upon monoaddition, the formation of the stable allylic cation was confirmed by trapping the resulting cation with tributyltin hydride, which yielded PIB with dihydrofuran functionality. Quenching with methanol resulted in the quantitative formation of 2-alkyl-5-PIB-furan. The stable allylic cation was found to be an efficient initiating species for the polymerization of methyl vinyl ether (MeVE), yielding P(IB-b-MeVE) block copolymers by sequential monomer addition with up to 75% crossover efficiency. 2-PIB-Fu, a polymeric capping agent, was obtained in quantitative yields in a reaction of PIB+ with 2-Bu3SnFu in Hex/CH3Cl 60/40 v/v in the presence of TiCl4 at −80 °C. In a subsequent reaction of 2-PIB-Fu with living PIB+, under conditions similar to capping PIB+ with 2-tBuFu, close to quantitative coupling of the two PIB chains was achieved. The concept of coupling a living cationic polymer with an ω-furan functional polymer to obtain AB-type linear block copolymers and for the synthesis of ABC- and AA‘B-type three-arm star-block copolymers is presented.

Near-monodisperse,n-alkyl, end-functionalized poly(methyl vinyl ether)s: Synthesis by living cationic polymerization and solution characterization

Water-soluble amphiphilic diblock copolymers were synthesized by the living cationic polymerization of methyl vinyl ether (hydrophilic block) and its subsequent termination with n-alcohols of chain lengths varying from one to eight, and three n-alkyl carboxylic acids with 10, 12, and 18 carbon atoms. Additionally, water and ethylene glycol were tested as terminating agents. The extent of the functionalization was determined using 1 H NMR spectroscopy. The cloud points of 1% w/w aqueous solutions of the polymers as determined by turbidimetry decreased from 32 to 21°C as the number of carbon atoms of the terminating agent increased. Aqueous GPC revealed micellization of the stearic acid-terminated block copolymer, while the other block copolymers existed mainly as unimers.

Poly(methyl vinyl ether-b-octadecyl vinyl ether): a New Non-ionic Surfactant

Block copolymers consisting of methyl vinyl ether (MeVE) units and octadecyl vinyl ether (ODVE) units were synthesized using the cationic living polymerization technique. The polymerization of MeVE was initiated with the trimethyl silyl iodide/1,1-diethoxyethane/ZnI 2 system at -40°C in toluene and the living polymer thus obtained was used as initiator for the polymerization of ODVE at 0°C. The combination of hydrophilic (PMeVE) and hydrophobic (PODVE) segments provides the block copolymers with non-ionic surfactant properties, which have been evaluated by measurement of the stabilities of water-decane emulsions.

Amphiphilic Block Copolymers by Sequential Living Cationic Polymerization: Synthesis and Characterization of Poly(isobutylene-b-methyl vinyl ether)

The living polymerization of methyl vinyl ether (MeVE) was achieved using initiators obtained by capping 2,4,4-trimethyl-2-chloropentane (TMPCl) with 1,1-diphenylethylene (DPE), or 1,1-ditolylethyl...

Quasiliving Carbocationic Polymerization. VIII. Quasiliving Polymerization of Methyl Vinyl Ether and Its Blocking from Quasiliving Poly(isobutyl Vinyl Ether) Dication

Abstract Quasiliving carbocationic polymerization of methyl vinyl ether (MVE) was achieved with the p-dicumyl chloride (p-DCC)/AgSbF6 initiator system by the slow and continuous monomer-addition (quasiliving) technique. A polar solvent (CH2Cl2) and a low reaction temperature (-70°C) were optimum for the quasiliving MVE polymerization. Under these conditions, the number-average molecular weight (M n) of poly(MVE) increased linearly with the cumulative weight of added monomer (WMVE), and linear M n versus WMVE plots passed through the origin. M n's were inversely proportional to the initial initiator (p-DCC) concentration. Reactions in a nonpolar solvent (toluene) at -70°C or in a polar solvent (CH2Cl2) at −30°C resulted in deviations from these quasiliving characteristics. Block polymerization of MVE from quasiliving poly(isobutyl vinyl ether) dications by the quasiliving technique (p-DCC/AgSbF6 initiator, CH2Cl2 solvent,(-70°C) led to novel isobutyl vinyl ether (IBVE)-MVE block polymers in high yield (>93 wt%) and at high blocking efficiency. The block polymers, most likely poly(MVE-b-IBVE-b-MVE), having M n = 10,900–14,000 [M n(center block) = 6,200–9,0001, were soluble in n-heptane and insoluble in water, and gave hazy homogeneous solutions when dissolved in methanol at room temperature.

Radiation-Induced Polymerization of Methyl Vinyl Ether

Abstract The radiation- induced polymerization of methyl vinyl ether under super-dry and wet conditions was studied. Little difference in the rates of polymerization was found. It seems clear that only an extremely slow free-radical polymerization was taking place. Possible reasons for the lack of concurrent cationic polymerization are discussed.

An investigation on the mechanism of homogeneous cationic polymerization of methyl vinyl ether by NMR spectroscopy

AbstractMethyl vinyl ether‐α.β‐d2 was synthesized and polymerized with BF3·OEt2 or stannic chloride‐trichloroacetic acid as catalyst at −78 up to 0°C in toluene or methylene chloride. The NMR spectra of the polymers were determined on nitromethane solutions and the triad tacticity was obtained from the methoxyl absorptions. Pentad resonances were observed on chlorobenzene solutions. Tetrad resonances were assigned from the methylene proton absorptions in the deuterium‐decoupled spectra, assuming that the polymerization proceeded according to the first‐order MARKOVIAN trial. It was found that the proportions of the two meso methylene protons were nearly equal irrespective of polymerization conditions and the mode of double bond opening was discussed.

NMR studies on the stereospecific polymerization of methyl vinyl ether. Part I. Polymerization by metal halides: Penultimate effect

AbstractMethyl vinyl ether (MVE) was polymerized under various conditions by BF3·O(C2H5)2 and SnCl4·CCl3CO2H catalysts. The effect of polymerization conditions on the steric structure of poly(methyl vinyl ether) (PMVE) was studied by NMR spectra. It was found that the triad isotacticity of PMVE decreased and the syndiotacticity and heterotacticity increased with increasing polarity of the solvent and increasing polymerization temperature. This result coincided with the qualitative conclusion estimated from softening point and infrared spectra. However, the variation of tacticity by the change of the polarity of a solvent was not so large as expected. There was no large difference between the behavior of BF3·O(C2H5)2 and SnCl4·CCl3CO2H as catalysts. From the relation between the difference of free energy of monomer addition due to the steric structure of the polymer and the polymerization temperature, it was concluded that the penultimate effect really existed and was due to only the difference in enthalpy in the MVE–BF3. O(C2H5)2 or MVE–SnCl4·CCl3CO2H systems. The penultimate effect was not greatly changed by the polymerization conditions in these systems.

NMR studies on the stereospecific polymerization of methyl vinyl ether. Part II. Polymerization by sulfuric acid–aluminum sulfate complex: Enantiomorphic catalyst sites model

AbstractHighly crystalline poly(methyl vinyl ether) (PMVE) was produced in toluene in a temperature range of 0 to −20°C. with the use of sulfuric acid–aluminum sulfate complex (SA catalyst). It was found from the NMR spectra that these polymers contained more than 50% of the triad isotactic fraction and the melting point of the unfractionated polymer was about 130°C. However, PMVE containing a large amount of the isotactic fraction was insoluble in nitromethane, so the triad tacticity of highly crystalline PMVE could not be quantitatively determined. The molecular weight of PMVE increased with increasing conversion and increasing polymerization temperature. This behavior is different from that in metal halide catalysts. Also, the stereoregularity of PMVE decreased with increasing monomer concentration. However, addition of a polar solvent and increasing the polymerization temperature had little effect on the stereoregularity of the polymer. The increase in the isotactic fraction at high catalyst concentration and the difference in the monomer composition in the copolymerization of methyl vinyl ether with 2‐chloroethyl vinyl ether by SA catalyst from that obtained by BF3·O(C2H5)2 suggest that the absorption of MVE on a catalyst surface is an important step in the propagation step by SA catalyst. The fraction of the triad tacticity calculated from the enantiomorphic catalyst sites model8 coincided with the experimental results. This fact shows that the steric structure of the adding monomer is determined only by the nature of the catalyst irrespective of the nature of a growing chain end. It is concluded, on considering also the results of the previous paper, that completely different factors can control the steric structure of a polymer even for the same monomer when different catalysts are used.

Stereoregular polymerization of methyl vinyl ether with fluoro aluminum initiators

AbstractThe reactions of HF, BF3, or certain organic fluorine compounds with AlCl3, (C2H5)3Al, or ethylaluminum chlorides in chlorinated hydrocarbons give rise to gels which exhibit pronounced stereoregular polymerization initiating ability toward methyl vinyl ether. The active sites are believed to involve species of the type RAlF4. Polymeric products having a wide range of stereoregularities are obtained. Several polymerization variables were examined. The reaction systems exhibit a variety of appearances and interesting rheological sequences. These are the consequences of differential solubility behaviors of the various stereoregular fractions. The most highly stereoregular fractions may be fabricated as fibers, films, or molded objects. Fractions of intermediate stereoregularity exhibit interesting emulsion‐forming properties. Stereoregularity is shown to afford a novel control over degree of water absorption in films.