2-chloroethyl Vinyl Ether Research Articles

Facile access to redox responsive self-healing coating materials via living cationic block copolymerization of styrene and 2-chloroethyl vinyl ether

Poly(alkyl vinyl ether)-based functional copolymers have wide applications in many high-tech areas. However, their synthesis is still challenging which limits their applications. This article describes the synthesis of an unprecedented redox-responsive polystyrene-block-poly(2-thioethyl vinyl ether) (PSt-b-PTEVE) diblock copolymers via sequential “water tolerant” cationic polymerization of St and CEVE, followed by post-polymerization transformation of the pendant -CH2CH2Cl functionalities of PCEVE segment to -CH2CH2SH functionalities. The initiating system enabled controlled cationic polymerization of styrene (St), yielding well-defined PSt (at least up to 22500 g/mol) with relatively low dispersity (Đ ≤ 1.36) and polystyrene-block-poly(2-chloroethyl vinyl ether) (PSt-b-PCEVE) diblock copolymers with acceptable dispersity values (Đ ≤ 1.38) thereof, demonstrating high chain-end fidelity. The controlled character of the cationic polymerization reaction was confirmed by linear kinetic plots, linear increase of Mns (with low Đs) and synthesis of PSts of changing Mns simply by varying initial [St]0/[Initiator]0 feed ratio. The synthesized PSt-b-PTEVE diblock copolymers exhibited redox responsivity and self-healing behaviour. The self-healing property of the PSt-b-PTEVE diblock copolymer was studied by optical microscopy. For this, first, a mechanical cut was introduced in the cross-linked PSt-b-PTEVE thin films and then images were taken at regular intervals to investigate the healing. These promising PSt-b-PTEVE diblock copolymers might have potential applications in many emerging areas, including functional coating.

Two-step degradable ABAC-type periodic poly(cyclic acetal)s synthesized by sequence-programmed monomer formation and subsequent polyaddition based on cyclotrimerization of one vinyl monomer and two aldehydes

ABAC-type periodic poly(cyclic acetal)s were synthesized via a two-step method consisting of the synthesis of a sequence-programmed cyclic trimers from one vinyl monomer and two bifunctional aldehydes (isophthalaldehyde or terephthalaldehyde) and the successive cyclotrimerization of the cyclic trimer with another vinyl monomer. The use of 1,1-diphenylethylene (DPE) was important for synthesizing the cyclic trimer in high yield because the successive cyclotrimerization and other side reactions were suppressed due to the steric hindrance of DPE. The ABA-type sequence-programmed cyclic trimer consisting of one DPE molecule (unit B) and two dialdehydes (unit A) possesses two unreacted aldehyde moieties; hence, the cyclic trimer successfully underwent successive cyclotrimerization with vinyl ethers (VEs) (unit C), such as 2-chloroethyl VE (CEVE) and ethyl 2-methyl-1-propenyl ether (EMPE). As a result, ABAC-type periodic poly(cyclic acetal)s with alternately arranged two phenyl rings and VE-derived side chains were produced. The two types of cyclic acetal structures in the main chain exhibited different acid degradability. Indeed, the CEVE-derived cyclic acetal structures were selectively degraded under acidic conditions at 60 °C for 15 min, which was followed by the subsequent degradation of the DPE-derived cyclic acetal structures in 24 h. In addition, the ABAC-type periodic polymers exhibited good thermal properties, which were attributed to the cyclic acetal structures.

Statistical Copolymers of N-Vinylpyrrolidone and 2-Chloroethyl Vinyl Ether via Radical RAFT Polymerization: Monomer Reactivity Ratios, Thermal Properties, and Kinetics of Thermal Decomposition of the Statistical Copolymers.

The radical statistical copolymerization of N-vinyl pyrrolidone (NVP) and 2-chloroethyl vinyl ether (CEVE) was conducted using the Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization technique, employing [(O-ethylxanthyl)methyl]benzene (CTA-1) and O-ethyl S-(phthalimidylmethyl) xanthate (CTA-2) as the Chain Transfer Agents (CTAs), leading to P(NVP-stat-CEVE) products. After optimizing copolymerization conditions, monomer reactivity ratios were estimated using various linear graphical methods, as well as the COPOINT program, which was applied in the framework of the terminal model. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the monomers' mean sequence lengths. Thermal properties of the copolymers were studied by Differential Scanning Calorimetry (DSC) and kinetics of their thermal degradation by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG), applying the isoconversional methodologies of Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS).

Alternating cationic copolymerization of vinyl ethers and sequence-programmed cyclic trimer consisting of one vinyl ether and two aldehydes for ABCC-type periodic terpolymer

Alternating cationic copolymerizations of 2-chloroethyl vinyl ether (CEVE; unit A) and cyclic trimers prepared from the cyclotrimerization of one vinyl monomer (unit B) and two aldehyde molecules (unit C) were...

Statistical Copolymers of n-Butyl Vinyl Ether and 2-Chloroethyl Vinyl Ether via Metallocene-Mediated Cationic Polymerization. A Scaffold for the Synthesis of Graft Copolymers.

The cationic statistical copolymerization of n-butyl (be) and 2-chloroethyl vinyl ether (CEVE), is efficiently conducted using bis(η5-cyclopentadienyl)dimethyl zirconium (Cp2ZrMe2) in combination with tetrakis(pentafluorophenyl)borate dimethylanilinum salt [B(C6F5)4]–[Me2NHPh]+, as an initiation system. The reactivity ratios are calculated using both linear graphical and non-linear methods. Structural parameters of the copolymers are obtained by calculating the dyad sequence fractions and the mean sequence length, which are derived using the monomer reactivity ratios. The glass transition temperatures (Tg) of the copolymers are measured by Differential Scanning Calorimetry (DSC), and the results are compared with predictions based on several theoretical models. The statistical copolymers are further employed as scaffolds for the synthesis of graft copolymers having poly(vinyl ether)s as a backbone and either poly(ε-caprolactone) (PCL) or poly(l-lactide) (PLLA) as side chains. Both the grafting “onto” and the grafting “from” methodologies are employed. The reaction sequence is monitored by Size Exclusion Chromatography (SEC), NMR and IR spectroscopies. The advantages and limitations of each approach are thoroughly examined.

Characteristics and Mechanism of Vinyl Ether Cationic Polymerization in Aqueous Media Initiated by Alcohol/B(C₆F₅)₃/Et₂O.

Aqueous cationic polymerizations of vinyl ethers (isobutyl vinyl ether (IBVE), 2-chloroethyl vinyl ether (CEVE), and n-butyl vinyl ether (n-BVE)) were performed for the first time by a CumOH/B(C6F5)3/Et2O initiating system in an air atmosphere. The polymerization proceeded in a reproducible manner through the careful design of experimental conditions (adding initiator, co-solvents, and surfactant or decreasing the reaction temperature), and the polymerization characteristics were systematically tested and compared in the suspension and emulsion. The significant difference with traditional cationic polymerization is that the polymerization rate in aqueous media using B(C6F5)3/Et2O as a co-initiator decreases when the temperature is lowered. The polymerization sites are located on the monomer/water surface. Density functional theory (DFT) was applied to investigate the competition between H2O and alcohol combined with B(C6F5)3 for providing a theoretical basis. The effectiveness of the proposed mechanism for the aqueous cationic polymerization of vinyl ethers using CumOH/B(C6F5)3/Et2O was confirmed.

Atmospheric degradation of 2-chloroethyl vinyl ether, allyl ether and allyl ethyl ether: Kinetics with OH radicals and UV photochemistry

Unsaturated ethers are oxygenated volatile organic compounds (OVOCs) emitted by anthropogenic sources. Potential removal processes in the troposphere are initiated by hydroxyl (OH) radicals and photochemistry. In this work, we report for the first time the rate coefficients of the gas-phase reaction with OH radicals (kOH) of 2-chloroethyl vinyl ether (2ClEVE), allyl ether (AE), and allyl ethyl ether (AEE) as a function of temperature in the 263–358 K range, measured by the pulsed laser photolysis–laser induced fluorescence technique. No pressure dependence of kOH was observed in the 50–500 Torr range in He as bath gas, while a slightly negative T-dependence was observed. The temperature dependent expressions for the rate coefficients determined in this work are:kOH,2ClEVE(T)=(9.0±2.0)×10−12exp(478±72T)cm3molecule−1s−1,kOH,AE(T)=(1.3±0.4)×10−11exp(442±91T)cm3molecule−1s−1,kOH,AEE(T)=(5.8±1.3)×10−12exp(563±62T)cm3molecule−1s−1,The estimated atmospheric lifetimes (τOH) assuming kOH at 288 K were 3, 2, and 4 h for 2ClEVE, AE and AEE, respectively. The kinetic results are discussed in terms of the chemical structure of the unsaturated ethers by comparison with similar compounds. We also report ultraviolet (UV) and infrared (IR) absorption cross sections (σλ and σ(ν˜), respectively). We estimate the photolysis rate coefficients in the solar UV actinic region to be less than 10−7 s−1, implying that these compounds are not removed from the atmosphere by this process. In addition, from σ(ν˜) and τOH, the global warming potential of each unsaturated ether was calculated to be almost zero. A discussion on the atmospheric implications of the titled compounds is presented.

Controlled Cationic Copolymerization of Vinyl Monomers and Cyclic Acetals via Concurrent Vinyl-Addition and Ring-Opening Mechanisms

Vinyl monomers and cyclic acetals were demonstrated to copolymerize with sufficient crossover propagation reactions in a controlled manner via the generation of long-lived species. Such unusual propagation reactions, mediated by the active species derived from different types of monomers, were shown to require an appropriate dormant–active equilibrium, achieved via the elaborate design of the initiating systems. The controlled copolymerization of 2-chloroethyl vinyl ether (CEVE) and 1,3-dioxepane (DOP) proceeded using SnCl4 as a catalyst in conjunction with ethyl acetate and 2,6-di-tert-butylpyridine, yielding multiblock-like copolymers as a result of several rounds of crossover reactions per chain. Under the same conditions, when 2-methyl-1,3-dioxolane (MDOL) was used instead of DOP, the polymerization proceeded in a highly controlled manner and involved more frequent crossover reactions. In addition, MDOL underwent almost no homopropagation reactions, unlike DOP. The nature of the cyclic acetal-derived ...

New semi-IPN PEMFC membranes composed of crosslinked fluorinated copolymer bearing triazole groups and sPEEK for operation at low relative humidity

The synthesis, processing, crosslinking, and characterization of original proton conducting membranes are presented. First, fluorinated terpolymers were obtained from the radical terpolymerization of chlorotrifluoroethylene (CTFE), 2-chloroethyl vinyl ether (CEVE) and glycerine carbonate vinyl ether (GCVE) followed by two chemical modifications into poly(IEVE-alt-CTFE)x-g-1H-1,2,4-triazole-3-thiol-co-(GCVE-alt-CTFE)y terpolymer that bear dangling cyclocarbonate and triazole functions (where IEVE stands for 2-iodoethyl vinyl ether). The successful grafting (overall yields >80%) of these terpolymers was monitored by 1H and 19F NMR spectroscopy and by thermal analyses (DSC and TGA) and did not shown any opening of the cyclocarbonate ring. Such fluorofunctional terpolymers were involved in the preparation of blend membranes with sulfonated PEEK (sPEEK), followed by the crosslinking in the presence of two telechelic diamines of different chain lengths via cyclocarbonate/amine reaction. The characterizations of these resulting membranes (thickness = 35–50 μm) in term of thermal stability (>200 °C under air), water uptake (as low as <20%), conductivity, and mechanical properties (strain–stress relationships and by dynamical mechanical analysis) were comprehensively investigated to understand the influence of the nature of the diamines, the crosslinking, and the presence of azole group on membrane microstructure. Proton conductivities of crosslinked blend membranes comprising such fluorinated polymer components functionalized with triazole at 140 °C and at low relative humidity (<25%) reached 4.3 mS cm−1 for a blend membrane containing 60%-wt of s-PEEK and 40%-wt of poly(CTFE-alt-IEVE)82%-g-1H-1,2,4-triazole-3-thiol86%-co-(CTFE-alt-GCVE)18% terpolymer. They displayed glass transition temperatures, Young modulus and tensile strengths up to 223 °C, 4 MPa and 6%, respectively.

Triblock and pentablock terpolymers by sequential base-assisted living cationic copolymerization of functionalized vinyl ethers

A series of novel, well-defined triblock and pentablock terpolymers of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiEGVE) were synthesized by sequential base-assisted living cationic polymerization.

From glycidyl carbonate to hydroxyurethane side-groups in alternating fluorinated copolymers

Fluoropolymers bearing five-membered cyclocarbonate pendant groups were synthesized by radical co- or ter-polymerization of chlorotrifluoroethylene (CTFE) with various vinyl ethers [glycerol carbonate vinyl ether (GCVE), ethyl vinyl ether (EVE) and 2-chloroethyl vinyl ether (CEVE)] in good yields. Poly[(CTFE-alt-EVE)-co-(CTFE-alt-GCVE)] and poly[(CTFE-alt-CEVE)-co-(CTFE-alt-GCVE)] terpolymers feature higher molecular weights than poly(CTFE-alt-GCVE) copolymers. Then, the first examples of fluorinated polymers bearing hydroxyurethane moieties (PFHUs) were prepared by the chemoselective reaction of the pendant cyclocarbonates with isopropylamine, leading to primary and secondary hydroxyl dangling groups. The chemical structure of these PFHUs was confirmed by FTIR analysis and 1D (1H, 13C, 135DEPT/APT) and 2D (COSY, HMQC) NMR spectroscopies. Size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyses of the PFHUs revealed a higher molecular weight and a decrease in the glass transition and decomposition temperatures, as compared to the parent cyclocarbonate polymers.

Synthesis and characterizations of alternating co- and terpolymers based on vinyl ethers and chlorotrifluoroethylene

The synthesis of new terpolymers based on chlorotrifluoroethylene (CTFE), 2-chloroethylvinyl ether (CEVE) and 1H,1H,2H,2H-perfluorodecyl vinyl ether (FAVE8), in 1,1,1,3,3-pentafluorobutane initiated by tert-butylperoxypivalate (TBPPI) and CF3˙ radicals is presented. The products were obtained in high yields and their composition was assessed by 1H and 19F NMR spectroscopy and elemental analysis, confirming the very good alternation between CTFE and vinyl ether (VE) monomeric units. The molecular weights of the resulting products were determined by size exclusion chromatography and their thermal properties, i.e. degradation temperature under air and glass transition temperature (Tg), were also assessed. The introduction of the fluorinated vinyl ether in the terpolymers did affect the thermal stability and induced a linear decrease of the Tg values of the resulting materials. Films were also cast from acetone to carry out water contact angle measurements that were higher for higher FAVE8 contents.

Design and Photonic Properties of Novel Fluorinated Copolymers Bearing Phthalocyanine Side Groups

The design and characterization of amorphous alternating copolymers endowed with a satisfactory thermal stability are reported. These alternating poly(CTFE-alt-CEVE) copolymers are synthesized by radical copolymerization of chlorotrifluoroethylene (CTFE) with 2-chloroethyl vinyl ether (CEVE), which are first modified into poly[CTFE-alt-(2-iodoethyl vinyl ether)] copolymers and then azidated in high yields. Alkynyl CF3-containing phthalocyanines (Pcs) are then grafted via a copper-catalyzed Huisgen dipolar 1,3-addition (“grafting onto”), hence providing fluorinated copolymers with different degrees of grafting (from 10 to 72%) of Pc dangling groups. Electronic spectral (absorption, excitation, and fluorescence) and photophysical properties (fluorescence lifetimes, τF, and quantum yields, ΦF) are evaluated.

A facile synthesis of clickable and acid-cleavable PEO for acid-degradable block copolymers

End-functionalized polyethylene oxides containing cleavable acetal and clickable azide terminal groups (PEO-acetal-N3 and N3-acetal-PEO-acetal-N3) were obtained by the reaction between commercially available PEOs and 2-chloroethyl vinyl ether using pyridinium p-toluenesulfonate. This results in acetal-linkages which can be further functionalized by nucleophilic displacement with sodium azide. Both reactions proceeded quantitatively to produce clickable and cleavable PEOs in good yields. The obtained PEOs were subsequently converted into macroinitiators for nitroxide-mediated polymerization (NMP) by “click” reaction with an alkyne functionalized alkoxyamine. Styrene polymerization from the macroinitiators proceeded successfully to give well-defined acid degradable block copolymers (PEO-acetal-PS and PS-acetal-PEO-acetal-PS), all of which were shown to have narrow molecular weight distributions (Mw/Mn ∼ 1.2). Significantly, highly ordered nanophase separated thin films of hexagonally-packed cylindrical PEO domains embedded in a PS matrix could be prepared from the PEO-acetal-PS diblock copolymers with removal of the PEO block by treatment with acid yielding nanoporous thin films with primary hydroxyl groups decorating the pores' interiors.

Thermoresponsive phase behavior of poly(2-chloroethyl vinyl ether- alt-maleic anhydride) solutions in propyl acetate/ n-alkane mixed solvents

Thermoresponsive phase behavior of poly(2-chloroethyl vinyl ether- alt-maleic anhydride) (P(CVE-MA)) in mixed solvent of propyl acetate (PrAc) and n-alkane has been investigated. At a proper solvent composition of PrAc/ n-octane, the polymer solution was transparent at lower temperature, and became turbid with heating, which suggest that this polymer solution exhibits lower critical solution temperature (LCST) type phase behavior. Controllability of the cloud point of the polymer solution was studied by light scattering technique. At the fixed polymer concentration of 1 mass%, the cloud point value changed from 76 °C to 31 °C with increasing the n-octane content from 6 to 16 mass% in the mixed solvent, with excellent linear relationship. The cloud point curve plotted against polymer concentration shifted to higher temperature with decreasing molecular weight of P(CVE-MA). The cloud point curve also shifted to higher temperature when the chain length of the added n-alkane became longer, and this result was explained by n-alkane's polarity and molecular size.

Kinetic study of the OH-initiated photo-oxidation of four unsaturated (allyl and vinyl) ethers under simulated atmospheric conditions

Using the relative rate technique, rate constants for the gas-phase reactions of hydroxyl radicals with n-propyl vinyl ether (k1), 2-chloroethyl vinyl ether (k2), allyl ether (k3) and allyl ethyl ether (k4) have been measured. Experiments were carried out at (298 ± 2) K and atmospheric pressure using N2 and ultra pure air as bath gas. Using isoprene, 1-methyl-1-cyclohexene, 2-methyl-2-butene, 3-buten-1-ol and 2-methyl-2-propen-1-ol as reference compounds, the following rate constants were derived: k1 = (11.0 ± 0.4) × 10−11, k2 = (9 ± 1) × 10−11, k3 = (6.8 ± 0.7) × 10−11 and k4 = (4.2 ± 0.7) × 10−11, in units of cm3 molecule−1 s−1. This is the first experimental detcermination of k2–k4. The rate constants obtained are compared with the previous literature data for corresponding alkenes reactions with OH and the observed reactivity trends are discussed. The atmospheric implications of the results are considered.

LCST-type phase behavior of poly(2-chloroethyl vinyl ether-alt-maleic anhydride) in n-butyl acetate

Novel polymer solutions exhibiting lower critical solution temperatures (LCSTs) have been studied. An alternating copolymer of 2-chloroethyl vinyl ether and maleic anhydride was synthesized through free-radical solution polymerization. This copolymer can exhibit LCST-type phase behavior in n-butyl acetate (BuAc) under relatively mild conditions at temperatures sufficiently below its boiling point. The effects of molecular weight, polymer concentration and addition of cosolvent on the polymer solution’s cloud point temperature (Tcp) were investigated. The Tcp value was nearly constant over a wide range of concentrations and increased when the polymer concentration was reduced below a certain value. The experimental LCST-type phase diagram can be reasonably described by Flory–Huggins theory. The addition of non-solvents could reduce the Tcp of the polymer solution in BuAc, whereas the addition of good solvents could increase the Tcp. These LCST-type phase behaviors may be attributed to specific polar interactions between the polymer and the solvent.

Lower critical solution temperature behavior of poly(2-chloroethyl vinyl ether-alt-maleic anhydride) in organic media

Lower critical solution temperature behavior of poly(2-chloroethyl vinyl ether- alt -maleic anhydride) in organic media

Living cationic polymerization of an azide-containing vinyl ether toward addressable functionalization of polymers

We first achieved the living cationic polymerization of azide-containing monomer, 2-azidoethyl vinyl ether (AzVE), with SnCl4 as a catalyst (activator) in conjunction with the HCl adduct of a vinyl ether [H-CH2CH(OR)-Cl; R  CH2CH2Cl, CH2CH(CH3)2]. Despite the potentially poisoning azide group, the produced polymers possessed controlled molecular weights and fairly narrow distributions (Mw/Mn ∼ 1.2) and gave block polymers with 2-chloroethyl vinyl ether. The pendent azide groups are easily converted into various functional groups via mild and selective reactions, such as the Staudinger reduction and copper-catalyzed azide-alkyne 1,3-cycloaddition (CuAAC; a “click” reaction). These reactions led to quantitative pendent functionalization into primary amine (NH2), hydroxy (OH), and carboxyl (COOH) groups, at room temperature and without any acidic or basic treatment. Thus, poly(AzVE) is a versatile precursor for a wide variety of functional vinyl ether polymers with well-defined structures and molecular weights. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1449–1455, 2010

New fluorinated polymers bearing pendant phosphonic groups for fuel cell membranes: Part 1 synthesis and characterizations of the fluorinated polymeric backbone

Radical copolymerizations of chlorotrifluoroethylene (CTFE) with vinyl ethers such as 2-chloroethyl vinyl ether (CEVE) and ethyl vinyl ether (EVE) were performed at 75 °C in the presence of peroxide initiator. Three copolymers were obtained and characterized by means of both NMR and elemental analysis. Then, the chlorine atoms in the side chains were converted into iodine atoms by nucleophilic substitution, which was monitored by 1H NMR spectroscopy. A series of five copolymers with different amounts of iodine atoms in the side chains were thus obtained. These copolymers exhibited molecular weight values of about 25,000 g mol −1, and the thermal analysis of the copolymers showed a starting degradation from about 220 °C. The T g values were in the range of 34–41 °C and showed a linear dependence versus the content of iodine atoms.