Synthesis and characterization of amphiphilic diblock copolymers of methyl tri(ethylene glycol) vinyl ether and isobutyl vinyl ether

Water-soluble diblock copolymers of methyl tri(ethylene glycol) vinyl ether (hydrophilic block) and isobutyl vinyl ether (hydrophobic block) of different molecular weights and composition were synthesized by living cationic polymerization. The molecular weight and comonomer composition of these copolymers were determined by GPC and ¹H NMR spectroscopy, respectively. Aqueous solutions of the copolymers were characterized in terms of their micellar behavior using dynamic light scattering, aqueous GPC, and dye solubilization. All the copolymers formed aggregates with the exception of a diblock copolymer with only two hydrophobic monomer units. The micellar hydrodynamic size scaled with the 0.61 power of the number of hydrophobic units, in good agreement with a theoretical exponent of 0.73. An increase in the length of the hydrophobic block at constant hydrophilic block length or an increase in the overall polymer size at constant block length ratio both resulted in lower critical micelle concentrations (cmcs). The cloud points of 1% w/w aqueous solutions of the polymers were determined by turbidimetry. An increase in the length of the hydrophobic block at constant hydrophilic block length caused a decrease in the cloud points of the copolymers. However, an increase in the overall polymer size at constant block length ratio led to an increase in the cloud point. © 1996 John Wiley & Sons, Inc.     

Thermal dissociation of ethylene glycol vinyl ether

The pyrolysis of ethylene glycol vinyl ether (EGVE), an initial product of 1,4-dioxane dissociation, was examined in a diaphragmless shock tube (DFST) using laser schlieren densitometry (LS) at 57 ± 2 and 122 ± 3 Torr over 1200-1800 K. DFST/time-of-flight mass spectrometry experiments were also performed to identify reaction products. EGVE was found to dissociate via two channels: (1) a molecular H atom transfer/C-O scission to produce C(2)H(3)OH and CH(3)CHO, and (2) a radical channel involving C-O bond fission generating ˙CH(2)CH(2)OH and ˙CH(2)CHO radicals, with the second channel being strongly dominant over the entire experimental range. A reaction mechanism was constructed for the pyrolysis of EGVE which simulates the LS profiles very well over the full experimental range. The decomposition of EGVE is clearly well into the falloff region for these conditions, and a Gorin model RRKM fit was obtained for the dominant radical channel. The results are in good agreement with the experimental data and suggest the following rate coefficient expressions: k(2,∞) = (6.71 ± 2.6) × 10(27) × T(-3.21)exp(-35512/T) s(-1); k(2)(120 Torr) = (1.23 ± 0.5) × 10(92) × T(-22.87)exp(-48?248/T) s(-1); k(2)(60 Torr) = (2.59 ± 1.0) × 10(88) × T(-21.96)exp(-46283/T) s(-1).     

Swelling behavior of amphiphilic hydrogels of copolymers of the vinyl ether of ethylene glycol and vinyl isobutyl ether,and their interaction with cationic surfactant

Amphiphilic hydrogels of copolymers of the vinyl ether of ethylene glycol and vinyl isobutyl ether were synthesized by -radiation-induced free radical polymerization. Hydrogels with certain copolymer compositions showed thermo-sensitive behavior in aqueous solutions. The swelling behavior of the hydrogels in cetylpyridinium bromide aqueous solution was studied. Increased swelling of the hydrogels was observed in the surfactant solutions. The increased swelling was more prominent for the hydrogels with a higher content of hydrophobic moiety in the copolymer composition, and with higher surfactant concentration. The reason for this phenomenon is discussed. Treatment of some hydrogels in the surfactant solutions resulted in higher swelling ability in distilled water with distinct thermo-induced contraction over a narrow temperature interval.     

Thermo‐ and pH‐sensitive amphiphilic gels of copolymers of vinyl ether of ethylene glycol

Novel thermo‐sensitive linear and crosslinked copolymers of vinyl ether of ethylene‐glycol and vinyl butyl ether have been synthesized by gamma‐irradiation copolymerization. The effect of comonomer hydrophobicity, neutral salts addition and nature of cations and anions on the position of lower critical soluble temperature of water‐soluble copolymers and swelling‐deswelling behavior of networks is demonstrated. The combination of thermosensitivity and pH sensitivity of hydrogels are realized in the case of crosslinked terpolymers. Copyright © 1999 John Wiley & Sons, Ltd.     

Thermoresponsive copolymers of methacrylic acid and poly(ethylene glycol) methyl ether methacrylate

Copolymers of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) were prepared and their cloud points in aqueous solution were studied as a function of comonomer ratio, solution pH, and presence of hydrophobic comonomers. Under acidic conditions, the cloud point falls below 0 °C for copolymers with between 25% to 60% ether content, because of the formation of hydrophobic H‐bonded ether–acid complexes. The cloud point also decreases with solution pH. For equivalent ether to acid ratios, the cloud point decreases with decreasing PEG chain length, because of the presence of a larger number of hydrophobic methyl and methacrylate groups. Similarly, the cloud point decreases upon incorporation of hydrophobic comonomers such as butyl, lauryl, or glycidyl methacrylates. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6095–6104, 2005     

Polystyrene nanoparticles based on poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers

The solubilization of styrene by poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers has been examined. From turbidity measurements the solubility limit of the monomer in the micelles was obtained and the distribution coefficients were evaluated. Dynamic light scattering revealed that below the solubility limit, solubilization leads to a slight increase in micelle size, while above the solubility limit, there is a dramatic increase in particle size and turbidity as oil-in-water emulsions are formed through coalescence of monomer-swollen micelles. Polymerizations carried out below the solubility limit using the graft copolymer micelles as templates resembled microemulsion polymerizations in nature and led to very fine sterically stabilized polystyrene latex particles. Through careful control of the monomer concentration and the polymerization temperature it was possible to obtain spherical nanosize latex particles with similar size to those of the micelle precursors (10 nm) up to 11% monomer by weight. Polymerizations above the solubility limit, on the other hand, showed similarities with emulsion polymerizations and resulted in larger particles with higher polydispersity.     

Composite proton-conducting membranes based on poly(ethylene glycol vinyl glycidyl ether)

Composite proton-conducting membranes in the form of interpolymer films are prepared in an aqueous medium from sulfo-acid-modified poly(ethylene glycol vinyl glycidyl ether) and poly(vinyl alcohol). The initial poly(hydroxysulfo acid) is synthesized through the radical polymerization of ethylene glycol vinyl glycidyl ether followed by modification with sodium sulfite via epoxy groups and treatment with a cationite in the H form. The proton-conducting membranes feature improved thermal stability (200–250°C), a breaking strength of 1.0–8.9 MPa, elasticity (a relative elongation at break of 1.0–8.2%), chemical resistance, and specific proton conductivity attaining 10^?1 S/cm after doping with orthophosphoric acid.     

Poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers: preparation and aqueous solution properties

A series of water-soluble, amphiphilic graft copolymers has been prepared by free-radical copolymerization of methoxypoly(ethylene glycol) macromonomers, with either methyl methacrylate or butyl methacrylate as the comonomers, in water/ethanol solvent mixtures. Lower molecular weight copolymers were obtained by increasing the concentration of the initiator, azobisisobutyronitrile (AIBN), used in the polymerization reaction. However, the route used also led to the formation of significant quantities of tetramethylsuccinodinitrile, a toxic byproduct resulting from the cage reaction of AIBN. Static fluorescence measurements using pyrene as a probe, along with 1H NMR experiments, showed that the graft copolymers form aggregates in water at very low concentrations (approximately 0.01 g l(-1)) with the pendant hydrophilic graft chains forming a stabilizing shell around the hydrophobic backbone. An increase in the hydrophile-lipophile balance of the graft copolymers was found to lead to smaller aggregates with lower aggregation numbers and highly swollen hydrophilic shells, as revealed by small angle neutron scattering (SANS).     

Identification and quantification of polyethylene glycol types in polyethylene glycol methyl ether and polyethylene glycol vinyl ether

Quantitative determination of polyethylene glycol (PEG) impurities in two monofunctional polyglycol types, PEG methyl ether (M-PEG) and PEG vinyl ether (V-PEG), has been carried out by reversed-phase liquid chromatography with evaporative light scattering detection (ELSD). In addition to optimizing the resolution between PEG and monofunctional PEG peaks, the major focus has been to determine the molecular weights of PEG impurities in M-PEG and V-PEG of diverse molecular weights. The latter is achieved by examining liquid chromatography–mass spectrometry (LC–MS) mass spectra of both monofunctional PEG and PEG in several cases, and matching peak retention times with those of available PEG standards for all M-PEG and V-PEG sample types. This information is helpful in selecting the appropriate PEG standard to determine PEG content in each sample type. ELSD response factors for various PEG standards have also been compared. It has been found that PEG standards with molecular weights from 1000 Da to 8000 Da show responses that are within 10% of each other. However, a low molecular weight PEG such as PEG 400, provides approximately 30% less response compared to its higher molecular weight counterparts.     

Reactions of selenium bromides with butyl vinyl ether

Russian Journal of Organic Chemistry -     

Synthesis of new,functionalized poly(butyl vinyl ether) oligomers and novel copolymers containing these materials

This paper reports the synthesis and characterization of new, functionalized poly(alkyl vinyl ether) oligomers, and block copolymers containing poly(alkyl vinyl ether) and poly(methyl methacrylate). Using the HI/ZnI₂ initiating system in nonpolar solvents (hexane, toluene) at −20°C, both monofunctional and difunctional poly(alkyl vinyl ether) oligomers of predicted molecular weights precisely terminated with aldehyde, primary hydroxyl and ester endgroups have been prepared. Novel diblock copolymers comprised of poly(methyl methacrylate) and poly(butyl vinyl ether) have also been synthesized using a combination of living cationic and living group transfer polymerization.     

Copolymerization of N-vinylpyrrole-2-carbaldehydes with styrene, N-vinylpyrrolidone, and ethylene glycol vinyl glycidyl ether

Polyfunctional reactive copolymers of N-vinylpyrrole-2-carbaldehydes with styrene, N-vinylpyrrolidone, and ethylene glycol vinyl glycidyl ether are synthesized in the presence of AIBN (2 wt %, 80°C, 50 h) with a yield of up to 98% and a molecular mass of up to 4800. The copolymers show paramagnetic behavior (N = 2.0 × 10¹⁵?2.0 × 10¹⁷ g^?1) and possess the properties of organic semiconductors (σ = 0.9 × 10^?11–2.8 × 10^?7 S/cm after doping with I₂).     

A highly efficient layered double hydroxide catalyst for direct ethoxylation of butyl acetate to oligo‐ethylene glycol butyl ether acetates

A novel synthetic route that directly inserts ethylene oxide into butyl acetate without any labile hydrogen to produce oligo‐ethylene glycol butyl ether acetates is developed using an efficient acid–base bifunctional catalyst. The layered double hydroxide materials, which have structures similar to that of hydrotalcite, are synthesized using co‐precipitation methods. After modification by organic acid, the as‐prepared catalysts exhibit higher butyl acetate conversion and ethylene oxide catalytic activity with narrow ethylene glycol butyl ether acetate adduct distribution. Copyright © 2016 John Wiley & Sons, Ltd.     

Interpolymer complexes of copolymers of vinyl ether of diethylene glycol with poly(acrylic acid)

 The complex formation reactions of poly(vinyl ether of diethylene glycol) as well as vinyl ether of diethylene glycol–vinyl butyl ether copolymers with poly(acrylic acid) have been studied in aqueous and alcohol solutions. The formation of interpolymer complexes which were stabilized by hydrogen bonds was shown. The effects of molecular weight of poly(acrylic acid) and the nature of the nonionic polymer on the composition and stability of interpolymer complexes were clarified. The critical pH values of complexation were determined for different systems with various molecular weights and hydrophobic–hydrophilic balances. The stability of the interpolymer complexes formed in aqueous and alcohol solutions with respect to dimethylformamide addition was evaluated. The role of hydrophobic interactions and the presence of active groups on stability of the interpolymer complexes is discussed. Received: 23 July 2001 Accepted: 27 September 2001     

Thermal decomposition of copolymers from ethylene with some vinyl derivatives

The thermal degradation of ethylene-vinyl acetate (EVA), ethylene-vinyl-3,5-dinitrobenzoate (EVDNB) and ethylene-vinyl alcohol (EVAL) copolymers have been studied using differential thermal analysis (DTA) and thermogravimetry (TG) under isothermal and dynamic conditions in nitrogen. Thermal analysis indicates that EVA copolymers are thermally more stable than EVDNB samples. The degradation of the copolymers considered occurs as an additive degradation of each component polyethylene (PE) and poly(vinyl acetate) (PVA), poly(vinyl-3,5-dinitrobenzoate) (PVDNB) or poly(vinyl alcohol) (PVAL). The apparent activation energy of the decomposition was determined by the Kissinger and Flynn-Wall methods which agree well.     

Mass transfer of acetylacetone,ethylene glycol mono-n-butyl ether and ethylene glycol monophenyl ether across water-carbon tetrachloride and water-chloroform interfaces

The interfacial mass transfer kinetics of acetylacetone (acac), ethylene glycol mono-_n-butyl ether (EGBE) and ethylene glycol monophenyl ether (EGPE) across water-carbon tetrachloride (Ccl₄) and water-chloroform (CHCl₃) interfaces were studied by stirring the two phases at various speeds, maintaining a quiescent interface with a constant area. In the analysis of data, two rate-determining steps consisting of a diffusion toward the interface and a mass exchange between the interface and bulk phases are considered. It is shown that the transfer of EGBE and EGPE in both CHCl₃ and Ccl₄ systems is controlled by the diffusion step even at high stirring speeds, whereas the transfer of acac in Ccl₄ is controlled by the interfacial exchange step at high stirring speeds. An irreversible transfer has been also observed in the EGBE and EGPE systems at low stirring speeds.     

Adhesive properties of ethylene and vinyl acetate copolymers

Surface properties of ethylene and vinyl acetate copolymers (EVAs) are considered depending on their composition and history of surface formation. The kinetics of structural transformations in the near-surface layers of copolymers is investigated. Relaxation times and the equilibrium state of the EVA surface are determined. The orrelation dependence between the surface energy of copolymers and their adhesive properties for substrates of different natures is constructed.     

Microstructure of the chain of alkyl (meth)acrylate copolymers with vinyl butyl ether synthesized by the compensation method

Russian Chemical Bulletin - Copolymers of butyl acrylate and methyl methacrylate with vinyl butyl ether in excess at reflux of the latter were synthesized under comparable conditions gradually...