Polymérisation anionique du méthacrylate de méthyle par les organo-alcalins-I

Pascault, J. P.; Kawak, J.; Golé, Jean; Pham, Quang Tho

doi:10.1016/0014-3057(74)90093-7

Cited by 31 publications

(5 citation statements)

References 20 publications

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“…Very similar results were obtained by Pascault, Kawak, Gole, and Pham, 22 for the anionic polymerization of MMA and by Elias, Goeldi, and Kamar 23 for the radical polymerization.…”

Section: (M)(r)supporting

confidence: 75%

Homogeneous Polymerization of Methyl Methacrylate Initiated by Potassium Salts of Methanol and t-Butyl Alcohol in the Presence of Cryptand [222]

Viguier

Collet

Schué

1982

Polym J

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ABSTRACT:Homogeneous polymerization of methyl methacrylate initiated by potassium salts of methanol and t-butyl alcohol was studied in toluene in the presence of cryptand [222). The polymers prepared were predominantly syndiotactic. The isotacticities increased slightly with an increase in temperature. More than thirty years ago, it was claimed that alkali metal salts of primary alcohols could not initiate the polymerization of methyl methacrylate (MMA) in ether.' More recently, the oligomerization of MMA by CH 3 0-jCH 3 0H solutions has been studied.Z· 3 Oligomers having a degree of polymerization up to six were isolated and characterized. Initiation proceeded by the addition of CH 3 0-to the double bond, and termination by protonation from the methanol.t-Alkoxides, n-butoxides, derivatives of poly(ethylene oxide) of alkali metals as well as ethylmagnesium alkoxides for the initiation of the homogeneous polymerization of methacrylic acid esters have been described in previous papers. 4 -10 It has also been shown that the polymerization of MMA by alkali metal salts of 2-methoxyethanol and like compounds can be carried out in aprotic dipolar solvents such as hexamethylphosphoramide, dimethyl sulfoxide, and dimethylacetamide." Polymerization was greatly promoted by these solvents, even when in small quantities. It is also well known that cryptands such as (I) complex cationic species very strongly and hence promote nucleophilic reactionsY Several studies on the polymerization using such complexing agents have been reported. 13 _,In this paper, we report on the homogeneous polymerization of MMA in toluene by potassium salts of methanol and t-butyl alcohol in the presence of cryptand (1). It was accepted, according to our previous communication, 17 that such complexing agents increase the reactivity of the alkoxide. (Potassium methoxide and t-butoxide are noted respectively MeOK and t-BuOK.) EXPERIMENTAL MaterialsThe purification of toluene and MMA as well as the experimental techniques are described elsewhere.17 Potassium salts of the alcohols were prepared by the reaction of potassium metal with an excess of alcohol in toluene followed by removing solvent and alcohol under vacuum at 100°C during at least 15 hours. This gave the alkoxides as snow-137

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“…Very similar results were obtained by Pascault, Kawak, Gole, and Pham, 22 for the anionic polymerization of MMA and by Elias, Goeldi, and Kamar 23 for the radical polymerization.…”

Section: (M)(r)supporting

confidence: 75%

Homogeneous Polymerization of Methyl Methacrylate Initiated by Potassium Salts of Methanol and t-Butyl Alcohol in the Presence of Cryptand [222]

Viguier

Collet

Schué

1982

Polym J

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“…Anionic Polymerization of MMA and Monomer I. All polymerizations were performed under an argon pressure of about [30][31][32][33][34][35][36][37][38][39][40] Torr in an all-Pyrex glass reactor, allowing the use of vacuum and argon sweeping cycles. DMF and the monomer and initiator solutions were introduced under argon from Schlenk vessels or through self-sealing rubber caps by using a syringe technique.…”

Section: Methodsmentioning

confidence: 99%

“…These characteristic features may be ascribed to slow initiation with respect to fast propagation, as already noticed for MMA in THF solution. [35][36][37][38] The sharp tacticity contrast between PMMA and the poly(zwitterion) obtained under similar conditions (DMF, Li+, -40 "C) is especially striking and requires further discussion (see Table VIII). PMMA is predominantly syndiotactic and shows here again only weak deviations from the two stereopropagation mechanisms ( P ( m / r ) = 0.833 and P ( r / m ) = 0.147).…”

Section: Stereoregularity Of the Radical Poly(zwitterions)mentioning

confidence: 96%

Poly(ammonium alkoxydicyanoethenolates) as new hydrophobic and highly dipolar poly(zwitterions). 2. Mechanistic aspects of the polymerization

Pujol-Fortin¹,

Galin²,

Galin³

1991

Macromolecules

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Some mechanistic aspects of the polymerization of 2,2-dicyano-l-[2-(2-(methacryloyloxy)-ethyl)dimethylammonio)ethoxy]ethenolate were studied to check the possible influence of the highly dipolar lateral zwitterionic group ( p N 26 D) on the polymerization of this methacrylate. Kinetics of the free-radical polymerization in homogeneous dimethylformamide (DMF) solution were analyzed by calorimetry. The molar heat of polymerization, = -58 kJemo1-1, is very similar to those generally observed for alkyl methacrylates. The increase of the activation parameters E, and A derived from the overall rate constant K (K = A exp(-E./RT) = (k,2fkd/kt)0.5) observed in the presence of preformed poly(zwitteri0n) in the reaction medium (E, = 71 f 2 kJ-mol-1, In A = 19.5 f 1 (A in (L.m01-~)~.5.s-l) with respect to blank experiments (E, = 61 f 2 kJ-mol-l, In A = 16 f 0.5 (A in (L-m01-1)0%-~) is not compatible with genuine template effects. Stereoregularity of the radical poly(zwitterions) (1H NMR of the a-CH3 backbone at 400 MHz) is barely sensitive to temperature within the range -20 to +140 O C and to solvent effects (trifluoroethanol, NaSCN (3 M) aqueous solution): the chains are significantly less syndiotactic ((mm) = 0.09 f 0.02, (mr) = 0.44 f 0.04, (rr) = 0.47 f 0.05) than PMMA. Anionic polymerization of the zwitterionic monomer may be initiated by fluorenyllithium in DMF solution at -40 "C: it results in heterotactic polymers ((mm) = 0.22, (mr) = 0.58, (rr) = 0.20), in sharp contrast with methyl methacrylate, probably as a result of strong specific ion-dipole interactions between the zwitterionic groups and the terminal reactive ion pair of the growing chain in the transition state.

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“…These data include poly(methyl methacrylate) and poly(ethyl methacrylate) obtained by octylpotassium, 16 biphenylpotassium 18 fluorenylpotassium 19 or potassium alkoxide 20 in polar solvents. Thus the anionic polymerization initiated with potassium compounds in a polar solvent such as tetrahydrofuran appears to be generally suitable for the formation of heterotactic polymers.…”

Section: T/°cmentioning

confidence: 99%

Heterotactic Polymers of α-Substituted Acrylic Acid Esters

Hatäda

Sugino

Ise

et al. 1980

Polym J

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ABSTRACT:Polymerizations of various methacrylates and 0(-(p-substituted phenyl)acrylates were studied in toluene and tetrahydrofuran by several anionic initiators. The polymerization with octylpotassium in tetrahydrofuran was found to be the most suitable for the formation of the heterotactic polymer, defined as the polymer containing more than 50% heterotactic triads. Methacrylic acid esters of the primary alcohol gave the heterotactic polymers, whose heterotactic contents increased with an increase in the bulkiness of the ester group. Methacrylic esters of secondary alcohol generally gave heterotactic polymers with octylpotassium in tetrahydrofuran. In the polymerizations of methacrylic acid esters of tertiary alcohol, the heterotactic contents decreased with an increase in the bulkiness of the ester group. A perfectly atactic polymer was obtained in the polymerization of methyl 0(-phenylacrylate with butyllithium in tetrahydrofuran, but it gave the heterotactic polymer when initiated with octylpotassium in tetrahydrofuran. Methyl 0(-pchlorophenylacrylate produced the heterotactic polymer in tetrahydrofuran with butyllithium as well as with octylpotassium. In the case of methyl 0(-p-bromophenylacrylate, the heterotactic polymer was obtained even in the polymerization in toluene with butyllithium. These results indicate that the acrylic acid ester having the bulkier substituent tends to give the.heterotactic polymer more easily by anionic initiator. KEY WORDSHeterotactic Polymer / Alkyl Methacrylate / ()(-Substituted Acrylate / Methyl Methacrylate / Methyl 0(-Phenylacrylate / Cyclohexyl Methacrylate / Octylpotassium / Fluorenylcesium/ 13 C-NMR Spectrum / Glass Transition Temperature/ Many papers have been published on polymerization in which highly isotactic or syndiotactic polymers were obtained. However, there have been few publications concerning the formation of heterotactic polymers. Heterotactic poly(vinyl alcohol) was reported by Nozakura et al. 1 • 2 and heterotactic poly(acetaldehyde) by Brame and Vogl,3 and Goodman and Brandrup. 4 A polymer having more than 50% portion ofheterotactic triads should be defined as a heterotactic polymer since the heterotactic contents can attain at most 50% even when the regulation in the polymerization is sterically random. The formation ofheterotactic polymer appears to be very interesting since a higher order of stereoregulation would be required for the heterotactic polymerization than for the isotactic or syndiotactic one.In our previous paper 5 the formation ofheterotactic polymers of methyl a-(p-bromophenyl)acrylate and methyl a-(p-chlorophenyl)acrylate was briefly reported. In this work, we have studied the anionic polymerizations of various methacrylates and aphenylacrylates under various conditions, and found that the bulkiness of a-substituent was one of the important factor necessary for the heterotactic growth in the polymerization and that the polymerization in tetrahydrofuran initiated with octylpotassium was suitable for the formation of the heterotactic ...

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Polymérisation anionique du méthacrylate de méthyle par les organo-alcalins-I

Cited by 31 publications

References 20 publications

Homogeneous Polymerization of Methyl Methacrylate Initiated by Potassium Salts of Methanol and t-Butyl Alcohol in the Presence of Cryptand [222]

Homogeneous Polymerization of Methyl Methacrylate Initiated by Potassium Salts of Methanol and t-Butyl Alcohol in the Presence of Cryptand [222]

Poly(ammonium alkoxydicyanoethenolates) as new hydrophobic and highly dipolar poly(zwitterions). 2. Mechanistic aspects of the polymerization

Heterotactic Polymers of α-Substituted Acrylic Acid Esters

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