Isobutyl Vinyl Ether Research Articles

Solubility of Monomers for Chain Polymerization in Ionic Liquids Predicted by the Conductor-Like Screening Model for Real Solvents

Ionic liquids have been extensively investigated as clean solvents for chain polymerization reactions, such as radical polymerization, anionic polymerization, and cationic polymerization. However, the low solubility of the monomers in ionic liquids often plagues the efficiency of these reactions. In this study, solubility of two typical vinyl monomers of p-methylstyrene (p-MeSt) and isobutyl vinyl ether (IBVE) were studied in 1750 possible ionic liquids (50 cations and 35 anions) by conductor-like screening model for real solvents. The influences of cation structures, anion structures, and ion chain length on the solubility were systemically studied. The interaction energies and σ-profiles were also employed to explain major factors on solubility. The results revealed that a larger size of the nonpolar region of the cation or anion results in the higher solubility for p-MeSt and IBVE, as well as the longer alkyl chain in cation or anion. In this study, a theoretical method for selecting ionic liquids for ...

Near‐Infrared Free‐Radical and Free‐Radical‐Promoted Cationic Photopolymerizations by In‐Source Lighting Using Upconverting Glass

AbstractA method is presented for the initiation of free‐radical and free‐radical‐promoted cationic photopolymerizations by in‐source lighting in the near‐infrared (NIR) region using upconverting glass (UCG). This approach utilizes laser irradiation of UCG at 975 nm in the presence of fluorescein (FL) and pentamethyldiethylene triamine (PMDETA). FL excited by light emitted from the UCG undergoes electron‐transfer reactions with PMDETA to form free radicals capable of initiating polymerization of methyl methacrylate. To execute the corresponding free‐radical‐promoted cationic polymerization of cyclohexene oxide, isobutyl vinyl ether, and N‐vinyl carbazole, it was necessary to use FL, dimethyl aniline (DMA), and diphenyliodonium hexafluorophosphate as sensitizer, coinitiator, and oxidant, respectively. Iodonium ions promptly oxidize DMA radicals formed to the corresponding cations. Thus, cationic polymerization with efficiency comparable to the conventional irradiation source was achieved.

Near-Infrared Free-Radical and Free-Radical-Promoted Cationic Photopolymerizations by In-Source Lighting Using Upconverting Glass.

A method is presented for the initiation of free-radical and free-radical-promoted cationic photopolymerizations by in-source lighting in the near-infrared (NIR) region using upconverting glass (UCG). This approach utilizes laser irradiation of UCG at 975 nm in the presence of fluorescein (FL) and pentamethyldiethylene triamine (PMDETA). FL excited by light emitted from the UCG undergoes electron-transfer reactions with PMDETA to form free radicals capable of initiating polymerization of methyl methacrylate. To execute the corresponding free-radical-promoted cationic polymerization of cyclohexene oxide, isobutyl vinyl ether, and N-vinyl carbazole, it was necessary to use FL, dimethyl aniline (DMA), and diphenyliodonium hexafluorophosphate as sensitizer, coinitiator, and oxidant, respectively. Iodonium ions promptly oxidize DMA radicals formed to the corresponding cations. Thus, cationic polymerization with efficiency comparable to the conventional irradiation source was achieved.

Halogen-Bonding-Mediated and Controlled Cationic Polymerization of Isobutyl Vinyl Ether: Expanding the Catalytic Scope of 2-Iodoimidazolium Salts.

Metal-free initiating systems for living cationic polymerizations are desirable from the viewpoint of environmentally benign polymer synthesis. We describe here the development of a halogen-bonding-mediated and controlled cationic polymerization of isobutyl vinyl ether (IBVE) using 2-iodoimidazolium salts as an organocatalyst. Due to the ionic nature of the catalysts, the polymerization should be performed in CH2 Cl2 . The HCl-adduct of IBVE was the most suitable initiator, and the polymerization was carried out at -10 °C under the catalyst concentration of 10 mm to suppress alcohol elimination from the polymer chain. The addition of a small amount of nBu4 NCl (0.02 equivalent) was effective to accomplish the controlled cationic polymerization and obtain polyIBVE, having the molecular weight distribution below 1.3.

Triflate esters as in-situ generated initiating system for carbocationic polymerization of vinyl ethers, isoprene, myrcene and ocimene

Thermo-induced carbocationic polymerization of isobutyl vinyl ether (IBVE), isoprene, myrcene and ocimene is reported using triflate esters as in-situ generated single-molecule initiating system. 3-Methyl-2-butenyl triflate is used for IBVE polymerization at room temperature resulting in polymers with Mn∼9500gmol−1 and Mw/Mn∼2. Triflate-ester initiated polymerization of isoprene leads to oligomers with branched and ultimately cross-linked structures. Myrcene cationic polymerization, in CH2Cl2 or cyclohexane, using 2-propenyl triflate and 1-(4-metoxyphenyl)ethyl triflate as initiators yields low molar mass oligomyrcenes with loss of olefinic protons. Ocimene cationic polymerization is reported for the first time.

Chemical surface modification of aluminum oxide nanoparticles with graft copolymer of aluminum oxide and poly(isobutyl vinyl ether) mechanochemically synthesized in vacuum at low temperature

Chemical surface modification of aluminum oxide (AO) nanoparticles with graft copolymer of AO and poly(isobutyl vinyl ether) (PIBVE) (AO-graft-PIBVE) was carried out by ball milling of AO nanoparticles with IBVE in vacuum at low temperature. The AO-graft-PIBVE was evidenced by FT-IR and 1H NMR spectra. The surface modified AO nanoparticles with mono-dispersed particle diameter exhibited structural blue color which was evidenced by photograph, optical spectroscopy (UV-Vis-NIR) and SEM image. The key atoms for the mechanochemical reactions were assigned by the net charge and the distribution of the HOMO and/or LUMO at each atom estimated by molecular orbital calculations. The reaction scheme is proposed; naked Al cations of AO (AO-Al+) were produced by ionic scission of aluminum-oxygen bond by ball milling and trapped at the surface of AO nanoparticles. The AO-Al+ reacted with IBVE, formed a novel bond between the Al-atom of AO-Al+ and the C-atom of IBVE, and resulted in AO-Al-IBVE+. The AO-Al-IBVE+ sequentially reacted to the C-atom of IBVE, and finally resulted in AO-graft-PIBVE. The PIBVE homopolymer was simultaneously produced by the ball milling of AO with IBVE in vacuum at low temperature. The key atoms for the reactions were assigned by the molecular orbital calculations.

Diversifying Cationic RAFT Polymerization with Various Counteranions: Generation of Cationic Species from Organic Halides and Various Metal Salts.

A combination of hydrogen chloride adduct of isobutyl vinyl ether (IBVE-HCl) and various metal salts (AgOTf, AgPF6, AgSbF6, NaBArF (BArF: [3,5-(CF3)2Ph]4B)) efficiently generated initiating cationic species with different low, weakly, or non-nucleophilic counteranions (OTf-, PF6-, SbF6-, BArF-) and induced a cationic reversible-addition-fragmentation chain-transfer (RAFT) or degenerative chain-transfer (DT) polymerization of IBVE, ethyl vinyl ether, p-methoxystyrene, and α-methylstyrene (αMS) in the presence of appropriate thiocarbonylthio compounds or thioethers as reversible chain-transfer agents. The polymerization behaviors in terms of polymerization rate, polymer molecular weight, terminal structure, and stereochemistry were affected by the counteranions, whereas the molecular weight control was achieved by appropriate RAFT or DT agents for all of these counteranions. With a weakly or noncoordinating BArF anion and a trithiocarbonate, a nearly atactic poly(IBVE) with a narrow molecular weight distribution (Mw/Mn < 1.1) was obtained. When using nonoxoanions, such as SbF6-, PF6-, and BArF-, in the presence of thioethers, controlled cationic polymerization of αMS was achieved while frequent irreversible β-proton elimination occurred using TfO-. Thus, this method widens the scope of living or controlled cationic polymerizations with various counteranions.

Metallocene-mediated cationic polymerization of vinyl ethers: Kinetics of polymerization and synthesis and characterization of statistical copolymers

ABSTRACTThe cationic polymerization of ethyl, n-butyl and iso-butyl vinyl ether, EVE, BVE and iBVE, respectively, was efficiently conducted using bis(η5-cyclopentadienyl)dimethyl hafnium, Cp2HfMe2, or bis(η5-cyclopentadienyl)dimethyl zirconium, Cp2ZrMe2 in combination with either tris(pentafluorophenyl)borate, B(C6F5)3, or tetrakis(pentafluorophenyl)borate dimethylanilinum salt, [B(C6F5)4]−[Me2NHPh]+, as initiation systems. The evolution of polymer yield, molecular weight and molecular weight distribution with time was examined. In addition, the influence of the initiating system, the monomer and the reaction conditions on the control of the polymerization was studied. Furthermore, statistical copolymers of EVE with BVE were prepared employing Cp2HfMe2 and [B(C6F5)4]−[Me2NHPh]+ as the initiation system. The reactivity ratios were estimated using both linear graphical and non-linear methods. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length, which were derived using the monomer reactivity ratios. The glass transition temperatures, Tg, of the copolymers were measured by Differential Scanning Calorimetry, DSC, and the results were compared with predictions based on several theoretical models. The kinetics of thermal decomposition of the copolymers along with the respective homopolymers was studied by thermogravimetric analysis within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies.

Cationic polymerization of vinyl ethers with alkyl or ionic side groups in ionic liquids

ABSTRACTControlled cationic polymerization of isobutyl vinyl ether was demonstrated to proceed in an ionic liquid (IL), 1‐butyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide, using a 1‐(isobutoxy)ethyl acetate/TiCl4 initiating system, ethyl acetate as an added base, and 2,6‐di‐tert‐butylpyridine as a proton trap reagent. Judicious choices of metal halide catalysts, counteranions of ILs, and additives were essential for controlling the polymerization. The polymerization proceeded much faster in the IL than in CH2Cl2, indicating an increased population of ionic active species in the IL due to the high polarity. Polymers with a relatively narrow molecular weight distribution were obtained in the IL with a bis(trifluoromethanesulfonyl)imide ( ) anion even in the absence of an added base, which suggested possible interactions of the counteranion of the IL with the growing carbocations. Moreover, the direct cationic polymerization of a vinyl ether with pendant imidazolium salts, 1‐(2‐vinyloxyethyl)‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide, proceeded in a homogeneous state in 1‐methyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide. The solubilities of the obtained polymers were readily tuned by counteranion exchange. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1774–1784

Synthesis of Biodegradable Copolymer of Poly(isobutyl vinyl ether)-co-Poly(ε-Caprolactone) using Half-Sandwich Metallocene Catalyst and their Application as Plasticizer for Poly(Vinyl Chloride)

ABSTRACTIn this work, we studied the synthesis of biodegradable copolymers of the type poly(isobutyl vinyl ether)-co-(ε-caprolactone) (PIBVE-co-PCL) using a homogeneous mono-cyclopentadienyltitanium catalyst and methylaluminoxane (MAO) as co-catalyst. These copolymers can also be used as plasticizers for flexible poly(vinyl chloride) (PVC), improving its thermal properties. The copolymer PIBVE-co-PCL could be synthesized with a high conversion (&gt;90%). The use of 39 wt.% of the copolymer in the formulation of PVC decreases its glass transition temperature (Tg) by -6.51 °C. By varying the copolymer composition it is possible to obtain PVC with different Tg values that could be used for different applications. A particular application where one could use this type of copolymer is in PVC formulations for the fabrication of blood bags. The toxicity of dioctyl phthalate (DOP), which is the more commonly used plasticizer for PVC, limits the use of these formulations for the mentioned purpose. The PVC plasticized with the biodegradable copolymer showed an increase in the degradation temperature, improving the thermal stability of the PVC formulation in comparison with the phthalates usually used as plasticizers.

Rapid living cationic polymerization of vinyl ethers by a single-molecular initiating system

Initiated by an organic molecule trifluoromethanesulfonimide (HNTf2) without any Lewis acid or Lewis base stabilizer, cationic polymerization of isobutyl vinyl ether (IBVE) takes place rapidly and the polymerization is proved to be in a controlled/living manner. The conversion of IBVE could easily achieve 99% in seconds. The product poly(isobutyl vinyl ether) is narrowly distributed and its molecular weight increases linearly with time and fits well with the corresponding theoretical value. This single-molecular initiating system also works well in the living cationic polymerization of ethyl vinyl ether. HNTf2 is considered playing multiple roles which include initiator, activator, and stabilizer in the polymerization. It is quite different from the hydrogen halide-catalyzed polymerizations of vinyl ethers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1373-1377

Cationic polymerization of vinyl ethers and p‐methoxystyrene by a benign initiating system: Silver salt/arylmethyl halide/dialkyl sulfide

ABSTRACTThree vinyl ethers (VEs: isobutyl vinyl ether, ethyl vinyl ether, and isopropyl vinyl ether) and an active styrene derivative, p‐methoxystyrene (pMOS), were employed for cationic polymerization using a benign initiating system, AgClO4/Ph2CHBr/dialkyl sulfide. Choosing a sulfide with suitable nucleophilicity was important for achieving controlled polymerization. Additionally, selecting an appropriate reaction temperature based on monomer reactivity was also crucial for suppressing side reactions. Highly controlled polymerizations of VEs and pMOS were further confirmed by proton nuclear magnetic resonance (1H NMR) and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS). In addition, the coordination of the arylmethyl cation to the added base obviously influenced the initiation, as demonstrated by 1H NMR analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 861–870

Synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by dinuclear half-metallocene catalyst and atom transfer radical polymerization

The synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by using the combination of metallocene catalyst and atom transfer radical polymerization (ATRP) has been tried. This synthetic method takes advantages of both metallocene catalyst to form stereoregular polymer with high activity and ATRP with the controlled molecular weights and low polydispersity. The recent dinuclear half-sandwich complexes of titanium with xylene bridge, [Ti(η5-cyclopentadienyl)Cl2L]2-ortho, meta-[CH2-C6H4-CH2] (L = Cl, L = O-2,6-iPr2C6H3 ) were successfully synthesized. These catalysts were characterized by 1H NMR, 13C NMR and elemental analysis. Copolymers have been characterized by using gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). The collected copolymers have got narrow molecular weight distribution (≤1.8) and the improvement of stereoregularity (racemo dyads, r, are from 45 % to 56 %).

Thioether-Mediated Degenerative Chain-Transfer Cationic Polymerization: A Simple Metal-Free System for Living Cationic Polymerization

Cationic degenerative chain-transfer polymerization of vinyl ethers and p-alkoxystyrenes was investigated using a series of thioethers as a reversible chain-transfer agent via the equilibrium between a growing carbocationic species and the resulting sulfonium intermediate in the presence of a small amount of triflic acid (TfOH) as a cationogen. The stable thioether, which was easily prepared from isobutyl vinyl ether (IBVE) and n-butanethiol, efficiently controls the molecular weight of the resulting poly(IBVE) up to Mn ∼ 1 × 105 with narrow molecular weight distributions (MWDs) (Mw/Mn ∼ 1.2). Upon increasing the bulkiness of the alkyl substituents in the thiols (R–SH; R: n-Bu < s-Bu < t-Bu) or those in the monomers (CH2═CHOR′, R′: ethyl < isobutyl < cyclohexyl), the MWDs became broader due to the slower formation of the sulfonium intermediate for the degenerative chain-transfer reaction. For p-methoxystyrene, thioethers derived from bulkier alkylthiols or more electron-rich thiophenols are more effective. A silyl-protected difunctional dithioether produced telechelic polymers possessing hydroxyl groups at both chain ends and stable thiol linkers in the middle of the polymer chains. These polymers were subsequently used in chain-extension reactions in conjunction with diisocyanates and diols as chain extenders to be converted into high molecular weight polymers linked via urethane linkages.

Novel method of the surface modification of the microcrystalline cellulose powder with poly(isobutyl vinyl ether) using mechanochemical polymerization

The surface modification of microcrystalline cellulose (MCC) powder with poly(isobutyl vinyl ether) (PIBVE) chains of block copolymers of MCC and PIVBE (MCC-block-PIBVE) was produced by ball milling of MCC with isobutyl vinyl ether (IBVE) in vacuum at 77K. The polymerization of IBVE was initiated by mechano-cations of MCC (MCC+) on the MCC powder surface in vacuum at 77K. MCC+s located on the surface of MCC powder were produced by heterogeneous scissions of the β-1,4 glycosidic linkages comprising MCC main chain by ball milling in vacuum at 77K, and existed on the powder surface of MCC in vacuum at 77K as cations isolated from counter mechano-anions. The counterion-free MCC+s on the powder surface of MCC interacted with IBVE during milling, covalently bonded to IBVE, and simultaneously formed counterion-free cations (MCC-IBVE+) on the MCC powder surface. The counterion-free MCC-IBVE+s initiated a novel cationic polymerization of IBVE on the surface of MCC powder under vacuum, produced MCC-block-PIBVE, and gave rise to a surface chemical modification of MCC powder with MCC-block-PIBVE. This scheme is supported by 1H NMR, FT-IR, ESR, GPC, and MO calculations.

Polymerization of vinyl ethers initiated by dendritic cations using flow microreactors

Cationic polymerization of vinyl ethers initiated by an electrogenerated dendritic diarylcarbenium ion in the presence of 2,6-di-tert-butylpyridine was developed using a flow microreactor. The carbocationic polymer end generated by polymerization of isobutyl vinyl ether was effectively trapped by various nucleophiles such as trimethyl(1-phenylvinyloxy)silane and allyltrimethylsilane to give polymers with very narrow molecular weight distribution. The block copolymerization of two vinyl ethers followed by trapping with nucleophiles was successfully accomplished to give structurally well-defined macromolecules.

A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base

ABSTRACTAryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me2S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2050–2058

In situ and readily prepared metal catalysts and initiators for living cationic polymerization of isobutyl vinyl ether: dual-purpose salphen as a ligand framework for ZrCl4and an initiating proton source

A well-defined catalyst, generated quantitativelyin situsimply by mixing ZrCl4and a salphen ligand was shown to induce the living cationic polymerization of isobutyl vinyl ether.

Cationic polymerization of isobutyl vinyl ether in an imidazole-based ionic liquid: characteristics and mechanism

Controlled cationic polymerization of IBVE was successfully achieved in an ionic liquid, and corresponding elementary reactions and a mechanism were proposed.

Radical copolymerisation of chlorotrifluoroethylene with isobutyl vinyl ether initiated by the persistent perfluoro-3-ethyl-2,4-dimethyl-3-pentyl radical

The radical copolymerisation of chlorotrifluoroethylene with isobutyl vinyl ether initiated by trifluoromethyl radicals generated by β-scission of a persistent radical is reported.