Polymerization Of Isobutyl Vinyl Ether Research Articles

Fast living cationic polymerization of vinyl ethers with iron(III) chloride in the presence of a cyclic ether: Most active and environmentally benign catalyst for the living cationic polymerization of vinyl ethers

The fast living cationic polymerization of isobutyl vinyl ether was demonstrated with FeCl3 as a Lewis acid catalyst in the presence of a cyclic ether. The reaction was completed in 15 s even under mild conditions and was 5 or 1000 times faster than the reaction with SnCl4 or EtAlCl2, respectively, in the presence of 1,4-dioxane. The faster reaction was attributed to the superior ability of FeCl3 to extract Cl− in comparison with the other two acids. In addition, the molecular weight distributions of the product polymers were invariably very narrow (weight-average molecular weight/number-average molecular weight < 1.1). Through the reduction of the basicity of a cyclic ether (e.g., 1,3-dioxolane), ultrafast living polymerization (97% in 3 s) was achieved.

Living cationic polymerization of isobutyl vinyl ether (II): Photoinduced living cationic polymerization in a mixed solvent of toluene and diethyl ether

AbstractA new method of preparation of living cationic polymer of isobutyl vinyl ether via photoinduced polymerization in the presence of diphenyliodonium iodide (DPII, initiator) and zinc iodide in a mixed solvent of toluene/diethyl ether, which was irradiated at −78°C for short period, was completed within 15 min. The reaction was allowed for further reaction in the dark until monomer was fully consumed. It was found that increase in the conversion of monomer to polymer during the irradiation is very limited. Confirmation of the linear dependence of number‐average molar mass of resulting polymer on % conversion together with the fact that polymerization proceeds until monomer consumption, and controllability of number‐average molar mass of resulting polymer, depending on the molar ratio of monomer and initiator, strongly suggests the living nature of this polymerization, unless reaction temperature becomes higher than 0°C, i.e., the absence of chain breaking process. The narrow molar mass distribution, whose polydispersity index values are less than 1.2, reveals that the rate of initiation where irradiation is usually completed within 15 min is much faster than that of propagation in cationic nature in this system. Effect of some major factors, such as solvent polarity and temperature, on the living nature of the polymerization was also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3581–3586, 2006

Cationic polymerization of isobutyl vinyl ether initiated with transition‐metal ate complexes

AbstractThe cationic polymerization of isobutyl vinyl ether was examined with transition‐metal ate complexes with trityl cation as initiators. The initiators were generated by the reaction of triphenylmethyl chloride [trityl chloride (TrCl)] with ate complexes of Nb, Mo, and W with lithium cation, which were obtained in situ by the reaction of the transition‐metal halides with anionic reagents (organolithium or lithium amide). When the polymerization was initiated with a mixture of TrCl and Li+[NbH5(NnBuPh)]−, the resulting poly(isobutyl vinyl ether)s had narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight = 1.13–1.20). Although the polymerization was supposed to be initiated by the electrophilic attack of the trityl cation, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis of the resulting poly(isobutyl vinyl ether)s revealed the presence of H at the α‐chain end. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2636–2641, 2006

Instant living cationic polymerization using SnCl4/EtAlCl2 with a weak Lewis base: Ultrafast polymerization in seconds

The living cationic polymerization of isobutyl vinyl ether in 1–2 s is demonstrated with SnCl4 and EtAlCl2 in the presence of a weak base, ethyl chloroacetate, at subzero temperatures. The reaction proceeds 105 times faster than the reaction with conventional EtAlCl2 systems in the presence of a stronger base such as ethyl acetate at 0 °C yet remains highly controlled, yielding polymers with the near theoretical number-average molecular weight and with narrow molecular weight distributions (weight-average molecular weight/number-average molecular weight = 1.03). Two Lewis acids play different important roles in this system: EtAlCl2 generates initiating species quantitatively from an adduct of isobutyl vinyl ether and acetic acid, whereas SnCl4 promotes rapid polymerization.

Synthesis of Oligo(isobutyl vinyl ether) with a Silyl Enol Ether End Group and their Aldol Reactions with Benzaldehyde

Cationic polymerizations of isobutyl vinyl ether (iBVE) were carried out in the presence of a difunctional silyl enol ether, 3,3-dimethylpent-2,4-(trimethylsilyloxy)-1,4-diene. This procedure gave oligomers with silyl enol ether end groups. The silyl enol ether groups reacted in Lewis acid mediated aldol reactions with benzaldehyde to give predominately the β-hydroxy ketone product at the chain end. Benzaldehyde could be added either prior to initiation (ab initio methodology) or at a time after the propagation of iBVE had completed (sequential methodology). The ah initio methodology was shown to produce similar materials to the sequential method but the latter required higher reaction temperatures.

Photo-induced living cationic polymerization of isobutyl vinyl ether in the presence of various combinations of halides of diphenyliodonium and zinc salts in methylene chloride

Living nature of photoinduced cationic polymerization of isobutyl vinyl ether (IBVE) in the presence of various combinations of diphenyliodonium halide (DPIX), a photocationic initiator and zinc halide (ZnX2) in methylene chloride has been investigated. Attainment of 100 % conversion and a linear relationship between % conversion and number average molar mass of the resulting polymer, strongly suggests the living nature of this system. Livingness of the polymerization system was observed irrespective to the type of halide anion of the initiator and zinc salts unless the reaction temperature is not higher than −30°C. The rate of polymerization decreases in the order of iodide > bromide > chloride when halide salt of DPIX and ZnX2 are used. It is postulated that the cationic initiation is started by the insertion of weakly basic monomer in to the activated C-X terminal of the monomer adduct which is a reaction product of monomer and HX, a photolytic product of DPIX, formed in situ during the photo-irradiation process. It was concluded that polymerization is initiated by the insertion of weakly basic monomer into activated C-X terminal of monomer adduct due to the pulling action of ZnX2, which successively producing a new polarized C-X terminal for the propagation in cationic nature. This led us to a conclusion that the living nature of this cationic polymerization is ascribable to the polarized C-X growing terminal, which is stable enough to depress the processes of chain transfer or termination process.

Cationic Polymerization of Vinyl Ethers in the Presence of Silyl Enol Ethers

AbstractSummary: Vinyl ether oligomers with reactive end groups were prepared by alkylation of silyl enol ethers during propagation. Silyl enol ethers were added to the cationic polymerization of isobutyl vinyl ether, ethyl vinyl ether and methyl vinyl ether. The polymerizations were carried out under non‐living conditions so that, in the absence of added silyl enol ether, MALDI TOF mass spectrometry gave evidence for end groups other than those derived from reaction with the methanol capping agent. Addition of either phenyl‐1‐(trimethylsilyloxy)ethylene or 1‐methoxyphenyl‐1‐(trimethylsilyloxy)ethylene significantly reduced the fraction of end groups derived from intramolecular termination reactions, such as elimination, at temperatures between 21 and −78 °C. However, as in living systems lowering the reaction temperature increased the proportion of chains with the desired chain‐end functionality (i.e. aryl ketone derived from alkylation of the silyl enol ether). α‐β Elimination also produced a population of isobutyl vinyl ether oligomers with α‐β unsaturated ketone end groups.Structure of an oligo(isobutyl vinyl ether) with a substituted phenyl ketone end group.imageStructure of an oligo(isobutyl vinyl ether) with a substituted phenyl ketone end group.

Organosilicon‐Assisted Transformation of Living Anionic into Living Cationic Polymerization

AbstractA novel method is described for transforming an anionic polymerization process into a cationic polymerization process assisted by organosilyl groups. The reaction of the p‐tolyldimethylsilyl end group of polystyrene and trifluoromethanesulfonic acid produced a silyl triflate end group that served as a macroinitiator for the living cationic polymerization of isobutyl vinyl ether. The SiO linkage in the block copolymers underwent specific cleavage by reaction with tetrabutylammonium fluoride.magnified image

Polymerization of vinyl ethers with transition‐metal catalysts: An examination of the stereoregularity of the formed polymers

AbstractThe polymerization of isobutyl vinyl ether (IBVE) and tert‐butyl vinyl ether (TBVE) was carried out with metallocene and nonmetallocene catalysts, and the stereoregularity of the formed polymers was examined with 13C NMR spectroscopy. IBVE afforded polymers with 63–68% dyad isotacticity by polymerization with mixtures of metallocene catalysts and methyl aluminoxane as a cocatalyst in toluene as a solvent. However, TBVE yielded polymers with 47–52% dyad isotacticity (21–28% triad isotacticity) under the same conditions, the isotacticity being lower than that of poly(isobutyl vinyl ether) (PIBVE). Nonmetallocene catalysts, including Ti, Zr, and Hf complexes with two phenoxy imine chelate ligands, provided PIBVE and poly(tert‐butyl vinyl ether) with 63–68 and 45–51% dyad isotacticity, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3938–3943, 2002

Mass spectrometric analysis of chain end functionalization inab initio cationic polymerization

Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and LC-ESI MS was applied in the analysis of ab initio chain end functionalization in cationic polymerization of isobutyl vinyl ether. Well-resolved mass spectra of vinyl ether oligomers were obtained. The MALDI spectra give information on polymerization and functionalization process, as well as chain end functionality and side reactions occurred in the system.

Phosphonates as non-salt-type latent initiators for vinyl ether polymerization

Phosphonates, O, O-di-1-phenylethyl phenylphosphonate ( 1), O, O-di- tert-butyl phenylphosphonate ( 2), and O, O-dicyclohexyl phenylphosphonate ( 3), were examined as non-salt-type latent initiators in the polymerization of isobutyl vinyl ether (IBVE), phenyl vinyl ether (PVE), and tri(ethylene glycol) divinyl ether (DVE-3). The polymerization of IBVE and PVE did not proceed below 90 and 120°C, but rapidly proceeded above these temperatures with 1, respectively. DVE-3 cured with 1 quantitatively at 150°C for 12 h to afford brown gel insoluble in common organic solvents. The phosphonates served as novel non-salt-type latent initiators in the polymerization of the vinyl ether monomers.

HEXA-ARMED STAR-SHAPED POLY(VINYL ETHER) VIA CONTROLLED CATIONIC POLYMERIZATION WITH A NEW HEXA-FUNCTIONAL INITIATOR

Reaction of hexa(methoxymethyl) melamine (HMMM) with trimethylsilyl iodide (TMSI) at −45°C, leads to quantitative formation of hexa(iodomethyl) melamine (HIMM), which, upon addition of ZnI2, acts as a hexa-functional initiator for the cationic polymerization of isobutyl vinyl ether (IBVE). Under the appropriate polymerization conditions, star-shaped, hexa-armed “living” polymers are obtained.

MALDI‐TOF‐MS analysis of living cationic polymerization of vinyl ethers. II. Living nature of growing end and side reactions

AbstractMatrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis revealed that the HCl–vinyl ether adduct/SnCl4/n‐Bu4NCl initiating system induced living cationic polymerization of isobutyl vinyl ether in CH2Cl2 at −78 °C, that is, the well‐resolved spectra demonstrated that the produced polymers consist of only one series of polymers carrying one initiator fragment at the α end and one methoxy group originated from quenching with methanol at the ω end. The polymer molecular weight as well as the terminal structure were unchanged even when the reaction mixtures were kept unquenched at −78 °C for an interval of more than five times longer than the reaction period after complete consumption of monomer, which indicates the long lifetime of the living end even under such starved conditions. In contrast, the polymers obtained at a higher temperature, −15 °C, showed an additional minor series of polymers formed via proton initiation, originating from adventitious water. Under the starved conditions, other side reactions occurred to generate minor series of polymers with an aldehyde ω end or a diisobutyl acetal ω end. Rather surprisingly, however, unsaturated CC end groups were not detected, which means the absence of β‐proton elimination under these conditions. © 2001 John Wiley &amp; Sons, Inc. J Polym Sci A: Polym Chem 39: 1249–1257, 2001

Stereoregulation in cationic polymerization. III. High isospecificity with the bulky phosphoric acid [(RO)2PO2H]/SnCl4 initiating systems: Design of counteranions via initiators

In the cationic polymerization of isobutyl vinyl ether (IBVE) with binary initiating systems consisting of a protonic acid as an initiator and a Lewis acid as an activator/catalyst, phosphoric acid derivatives [(RO) 2 POOH] coupled with SnCl 4 gave highly isotactic poly(IBVE)s, whereas those with a bulky substituent (R), [C 4 H 9 CH(C 2 H 5 )CH 2 O] 2 POOH (7) and (n-C 10 H 21 ) 2 POOH (8), led to the highest isotacticity [meso dyad (m) = 86%]. In contrast, isospecificity was lower with IBVE-HCl and CF 3 COOH under the same conditions. From the effects of the polymerization temperature (-78 to 0 °C), it was concluded that the high isospecificity with 7 and 8 was due to an enthalpic factor.

“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.

A new multifunctional initiator system for the living cationic polymerization of vinyl ethers

Combination of hexa(chloromethyl)melamine (HCMM) and zinc chloride was found to be a multifunctional initiator system for the living cationic polymerization of isobutyl vinyl ether. HCMM was synthesized by reaction of hexa(methoxymethyl)melamine and boron trichloride. Characterization of the polymers by means of GPC and 1H NMR showed that initiation was rapid and quantitative and that the initiator is hexafunctional, leading to six-armed star-shaped polymers.

Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. III. Benzoic acid and related weakly acidic carboxylic acids for the living polymerization of isobutyl vinyl ether

The cationic polymerization of isobutyl vinyl ether with weakly acidic benzoic acids (1 and 4) and related carboxylic acids (3 and 5) in conjunction with SnBr4 led to living polymers with narrow molecular weight distributions (MWDs). The steric effects of the phenyl group directly connected to the carbonyl group in the carboxylate counteranion on the living nature and the polymer MWDs are discussed.

Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. III. Benzoic acid and related weakly acidic carboxylic acids for the living polymerization of isobutyl vinyl ether

The cationic polymerization of isobutyl vinyl ether with weakly acidic benzoic acids (1 and 4) and related carboxylic acids (3 and 5) in conjunction with SnBr4 led to living polymers with narrow molecular weight distributions (MWDs). The steric effects of the phenyl group directly connected to the carbonyl group in the carboxylate counteranion on the living nature and the polymer MWDs are discussed.

Aromatic Acetals as New Initiators for Cationic Polymerization of Isobutyl Vinyl Ether

A series of aromatic acetals (1) from substituted phenols [CH3CH(OiBu)OAr; Ar = C6H5, p-CH3OC(O)C6H4, p-CH3C(O)C6H4, p-NO2C6H4, 4-NO2-2,6-di-C6H5−C6H2, o-CH3C(O)C6H4] were employed as new initiators in conjunction with Lewis acids (MtXn) for the living cationic polymerization of isobutyl vinyl ether (IBVE). Most of them were quantitatively synthesized by the addition of the corresponding phenols to IBVE. When coupled with aluminum chloride (AlCl3), 1 gave polymers with broad molecular weight distributions (MWDs), whereas the addition of ethyl acetate (10 vol %) to these systems led to the formation of controlled polymers whose number-average molecular weights (Mn) were directly proportional to monomer conversion, with relatively narrow distributions (Mw/Mn ∼ 1.2). The aromatic acetals in conjunction with tin halides (SnX4; X = Cl, Br) gave relatively high meso contents (81%) in toluene at −78 °C.

Matrix-assisted laser desorption ionization time of flight mass spectrometry analysis of living cationic polymerization of vinyl ethers. I. Optimization of measurement conditions for poly(isobutyl vinyl ether)

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was utilized for the analysis of polymers obtained by the living cationic polymerization of isobutyl vinyl ether (IBVE) with the HCl-VE adduct/SnCl4/n-Bu4NCl initiating system in CH2Cl2 at −78 °C. Under optimized analysis conditions, well-resolved spectra were obtained for samples with number-average molecular weights of ≤104 with the use of 1,8-dihydroxy-9(10H)-anthracenone (dithranol) as a matrix and sodium trifluoroacetate as an added salt. The MS spectra showed only one series of peaks separated exactly by the mass of the IBVE. The observed mass of each peak was in good agreement with the theoretical one, which possesses one initiator fragment at the α end and one methoxy group originated from quenching with methanol at the ω end. Thus, detailed end group analysis is possible for poly(VE). © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4023–4031, 2000