Cationic Polymerization Of Isobutyl Vinyl Ether Research Articles

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.

Cationic polymerization of isobutyl vinyl ether coinitiated with heteropolyacid or its salts in aqueous medium

The suspension cationic polymerization of isobutyl vinyl ether (IBVE) in aqueous medium could be achieved by using H3PW12O40, AlPW12O40, FePW12O40, K3PW12O40, or Na3PW12O40 as efficient water-tolerant coinitiators in the presence of HCl. The addition reaction of IBVE with H2O occurred to form IBVE–H2O adduct and then subsequent decomposition immediately took place or turned to acetaldehyde diisobutyl acetal (A) in the presence of AlPW12O40, and (A) decomposed rapidly to form 2-isobutanol (B) and acetaldehyde (C). Cationic polymerization of IBVE in aqueous medium was promoted greatly with increasing HCl concentration and proceeded extremely rapidly to get high polymer yield even at low concentration of AlPW12O40 of 0.3 mM. A sufficient amount of HCl was needed to decrease the hydrolysis of initiator IBVE–HCl and to accelerate the polymerization in aqueous medium simultaneously. The yield and molecular weight of poly(IBVE) increased with increasing concentrations of HCl and AlPW12O40 or with decreasing temperature. The isotactic-rich poly(IBVE)s with m diad of around 60%, having Mn of 1200–4500 g mol−1 and monomodal molecular weight distribution could be obtained via cationic polymerization of IBVE in aqueous medium. This is the first example of cationic polymerization of IBVE in aqueous medium coinitiated by heteropolyacid and its salts. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Heterogeneously Catalyzed Living Cationic Polymerization of Isobutyl Vinyl Ether Using Iron(III) Oxide

Heterogeneously catalyzed living cationic polymerization of isobutyl vinyl ether (IBVE) with Fe2O3 in the presence of an added base is described. Cationic polymerization of IBVE using Fe2O3 in conjunction with ethyl acetate or 1,4-dioxane and IBVE−HCl, a suitable cationogen, proceeded smoothly in a heterogeneous system to produce polymers with very narrow molecular weight distributions (Mw/Mn ≤ 1.1). The living polymerization was also achieved under unfavorable conditions: at higher temperature (30 °C) or in the presence of a small amount of water. Furthermore, Fe2O3 was readily separable from product polymers according to simple procedures. The reused Fe2O3 was very similar in catalytic activity to the virgin counterpart even after multiple use, producing nearly monodisperse polymers.

“LIVING-LIKE” CATIONIC POLYMERIZATION OF ISOBUTYL VINYL ETHER INITIATED BY CARBOXYL GROUPS ON CARBON BLACK SURFACE/ETHYLALUMINUM DICHLORIDE SYSTEM IN THE PRESENCE OF 1,4-DIOXANE

The effect of 1,4-dioxane as an added base on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups on carbon black surface/ethylaluminum dichloride (EtAlCl2) system was investigated. Although the cationic polymerization of IBVE by carbon black/EtAlCl2 system the absence of 1,4-dioxane instaneously proceeded and the monomer conversion achieved 100% within a minute. The molecular weight distribution (MWD) of polyIBVE obtained was very broad. On the contrary, the MWD of polyIBVE obtained was very narrow and narrower than that obtained from the carbon black/ZnCl2 initiating system by the addition of 1,4-dioxane. The number-average molecular weight (Mn) of polyIBVE obtained was directly proportional to monomer conversion in the cationic polymerization. However, the Mn of polyIBVE obtained from the polymerization by the initiating system in the the presence of 1,4-dioxane was smaller than that of the calculated value, assuming that polyl(IBVE) chain forms per unit carboxyl group on carbon black surface. It was concluded that carbon black/EtAlCl2 initiating systems in the presence of 1,4-dioxane has an ability to initiate “living-like” cationic polymerization of IBVE based on the above results. PolyIBVE was grafted onto a carbon black surface after quenching the above “living-like” cationic polymerization systems with methanol.

Cationic polymerization behavior of isobutyl vinyl ether with arenesulfonates as non‐salt‐type latent thermal initiators

Substituted and unsubstituted benzenesulfonic acid cyclohexyl esters (1–7) were synthesized, and their possibility as latent thermal initiators in the cationic polymerization of isobutyl vinyl ether (IBVE) was examined to develop novel non-salt type latent cationic initiators. Thermal decomposition of cyclohexyl p-nitrobenzenesulfonate (2) in C6D6 at 80°C proceeded to exclusively afford cyclohexene as well as p-nitrobenzenesulfonic acid. Cationic polymerization of IBVE with 1 mol % of an arenesulfonate (1–6) in bulk was carried out at 40–100°C for 12 h. No polymerization took place below 50°C, while the consumption of IBVE depending on both the polymerization temperature and the structure of the arenesulfonates was observed above 60°C. The obtained polyIBVEs showed bimodal GPC curves in several cases, revealing the intervention of two independent propagation species in the polymerization. The cationic polymerization of IBVE with cyclohexyl 2,4,6-triisopropylbenzenesulfonate (7) at 80°C confirmed the acceleration effect of bulkiness on the polymerization rate. It was concluded that the polymerization was largely dependent on both electronic and steric factors of the aryl groups of the initiators which were directly related to the stability of the sulfonate anions. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 293–301, 1999

Cationic polymerization behavior of isobutyl vinyl ether with arenesulfonates as non-salt-type latent thermal initiators

Substituted and unsubstituted benzenesulfonic acid cyclohexyl esters (1–7) were synthesized, and their possibility as latent thermal initiators in the cationic polymerization of isobutyl vinyl ether (IBVE) was examined to develop novel non-salt type latent cationic initiators. Thermal decomposition of cyclohexyl p-nitrobenzenesulfonate (2) in C6D6 at 80°C proceeded to exclusively afford cyclohexene as well as p-nitrobenzenesulfonic acid. Cationic polymerization of IBVE with 1 mol % of an arenesulfonate (1–6) in bulk was carried out at 40–100°C for 12 h. No polymerization took place below 50°C, while the consumption of IBVE depending on both the polymerization temperature and the structure of the arenesulfonates was observed above 60°C. The obtained polyIBVEs showed bimodal GPC curves in several cases, revealing the intervention of two independent propagation species in the polymerization. The cationic polymerization of IBVE with cyclohexyl 2,4,6-triisopropylbenzenesulfonate (7) at 80°C confirmed the acceleration effect of bulkiness on the polymerization rate. It was concluded that the polymerization was largely dependent on both electronic and steric factors of the aryl groups of the initiators which were directly related to the stability of the sulfonate anions. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 293–301, 1999

Atom Transfer Radical Polymerization of Poly(vinyl ether) Macromonomers

The present paper focuses on the atom transfer radical polymerization (ATRP) of vinyl ether (VE) based macromonomers with a methacryloyl group at the chain end. Living cationic polymerization of isobutyl VE (IBVE) initiated with the HCl adduct of a VE carrying a pendant methacryloyl group in conjunction with ZnI2 yielded the macromonomer (MA-PIBVE) with a narrow molecular weight distribution (MWD) (Mw/Mn < 1.1). The ATRP of MA−PIBVE was carried out using a halide initiator and the CuBr/4,4‘-di-n-heptyl-2,2‘-bipyridine catalytic system. The number-average molecular weight of the polymacromonomer increased in proportion to the monomer conversion, while the MWDs stayed fairly narrow (Mw/Mn ∼ 1.2). Thus a novel type of polymacromonomers with controlled chain lengths for both the backbone and the side chain have been synthesized through a combination of living cationic polymerization and ATRP techniques.

Role of added Lewis base and alkylaluminum halide on living cationic polymerization of vinyl ether

AbstractIn the living cationic polymerization of isobutyl vinyl ether (IBVE) by the CH3CH (OiBu) OCOCH3 (1)/EtAlCl2 initiating system in the presence of the added base in hexane at +40°C, the stability of the initiating system 1/EtAlCl2, which form initiating species CH3CH⊕ (OiBu) derived from 1, was investigated. In the presence of the Lewis base such as ethyl acetate or 1,4‐dioxane, the active species was stable for 300 min even at +40°C in the absence of IBVE, and the living polymers were quantitatively obtained by adding IBVE. However, the active species was partly consumed by side reactions during the standing time for 60 min in the presence of a less basic additive such as ethyl benzoate, and about 50% of the active species was deactivated in the presence of methyl chloroacetate. Consequently, in the case of a less basic additive such as methyl chloroacetate (which was effective for the fast living polymerization), it can be seen that the careful selection of polymerization conditions was required. The living polymerization rate was dependent on the second order of EtAlCl2 concentration. EtAlCl2 induced the cleavage of 1 into CH3CH⊕ (OiBu) and EtAl⊖Cl2(OCOCH3), and the reactivity of CH3CH⊕ (OiBu) and propagating carbocation may be controlled by EtAl⊖Cl2(OCOCH3) with the aid of other EtAlCl2. Et1.5AlCl1.5 exists as a bimetallic complex of EtAlCl2 and Et2AlCl, and it is expected that the polymers having a bimodal molecular weight distribution will be obtained due to two kinds of counteranions coming from EtAlCl2 and Et2AlCl. However, in the cationic polymerization of IBVE by 1/Et1.5AlCl1.5 in the presence of ethyl acetate, the living polymer exhibiting a unimodal and very narrow molecular weight distribution was obtained. Thereby, it was suggested that the counteranions, EtAl⊖Cl2(OCOCH3) and Et2Al⊖Cl(OCOCH3), exchange rapidly with each other. © 1994 John Wiley &amp; Sons, Inc.