Alternating Copolymerization of Methyl α-Phenylacrylate and Various Methacrylates

Yuki, Heimei; Ohta, Koji; Hatäda, Koichi; Ishikawa, Hiroyuki

doi:10.1295/polymj.11.323

Cited by 29 publications

(37 citation statements)

References 10 publications

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“…18 The utilization of the lithium tertiary alkoxides such as lithium tert-butoxide as initiator and nonpolar solvents gives highly isotactic polymers. 19 The moderate isotacticity of the present sample is reported with the fact that it was possible to examine only the chloroform soluble fraction.…”

Section: Nmr Features Of Anionic Poly(tfema)mentioning

confidence: 99%

13C NMR Characterization of Polymers from 2,2,2-Trifluoroethyl Methacrylate

Passaglia

Aglietto

Ciardelli

et al. 1994

Polym J

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ABSTRACT:In an attempt to develop structural characterisation of polymers from fluorinated acrylic derivatives, a detailed 13 C NMR analysis of free radical and anionic poly(2,2,2-trifluoroethyl methacrylate) (poly(TFEM)) was performed as compared to relevant literature studies concerning the corresponding methyl methacrylate (MMA) polymers. On the other side, the moderately syndiotactic microstructure of the poly(TFEM) samples fits very well with that of corresponding poly(MMA) samples and can be interpreted on the basis of the same statistical distribution of triads. Thus it appears that the presence of the -CHr--CF 3 group does not affect in a determining way the stereochemistry of the polymerization. According to this final statement, anionic initiators give prevailingly isotactic poly(TFEM) as detected by 13 C NMR.

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Section: Nmr Features Of Anionic Poly(tfema)mentioning

confidence: 99%

13C NMR Characterization of Polymers from 2,2,2-Trifluoroethyl Methacrylate

Passaglia

Aglietto

Ciardelli

et al. 1994

Polym J

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“…When the formation of high molecular weight product (Mn 2 x 10 4 ) was expected, the polymer was recovered by precipitation from the reaction mixture with hexane, followed by filtration and drying in vacuo. 1 Hand 13C NMR spectra were measured on a JNM-GX500 or JNM-FXIOO NMR spectrometer. In the 1 H NMR spectra of poly(EMA) and copolymer of EMA with MMA measured in CDCI 3 at 55°C and at 100 MHz, the methyl proton signals of ester group in EMA unit overlapped with a-methyl proton signals for the isotactic sequence.…”

Section: Experimentalsmentioning

confidence: 99%

Highly Isotactic and Living Polymerization of Ethyl Methacrylate with t-C4H9MgBr in Toluene and the Preparation of Block and Random Copolymers with High Stereoregularity

Kitayama

Ute

Yamamoto

et al. 1990

Polym J

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ABSTRACT:The polymerization of ethyl methacrylate (EMA) with t-C4H9MgBr in toluene at low temperature gave a highly isotactic polymer as in the case of living and highly isotactic polymerization of methyl methacrylate (MMA) with t-C4 H g MgBr. Although the molecular weight distribution (MWD) of the poly(EMA) was bimodal, both species giving higher and lower molecular weight fractions contributed to the formation of highly isotactic block copolymers with bimodal MWD, indicating the living nature of both species. The polymerization of EMA with the living anion of isotactic PMMA formed with t-C4H g MgBr gave a highly isotactic block copolymer with unimodal MWD. This suggests that the multiplicity of active species observed in the polymerization of EMA with t-C4H 9MgBr was caused by the initiation of EMA with t-C4 H g MgBr. Conventional copolymerization of EMA and MMA afforded a highly isotactic copolymer with bimodal MWD, confirming the above consideration. 13C NMR spectrum of the copolymer indicated the comonomer sequence to be random. Glass transition temperatures of the isotactic and syndiotactic copolymers of EMA and MMA could be changed from 8 to 120°C by changing composition and tacticity.KEY WORDS Isotactic Living Polymerization / Anionic Polymerization / Multiplicity of Active Species / Copolymer / Glass Transition Temperature / Methyl Methacrylate / Ethyl Methacrylate / 13 C NMR / Many papers have been published on the stereospecific polymerization of methacrylates with various anionic initiators. Isotactic polymethacrylates are usually prepared in non-polar solvents by anionic initiators such as alkyllithium or Grignard reagent. 1 ,2 However, most of the polymerization reactions cannot be fully controlled owing to side reactions and multiplicity of active species, making the molecular weight distribution (MWD) of the resulting polymer broad. Recently, we found that polymerization of methyl methacrylate (MMA) with t-C4H9MgBr prepared in diethyl ether gave highly isotactic poly(methyl methacrylate) (PMMA) with narrow MWD in a living manner in toluene at -78°C. 3,4 Stereoregularity in the anionic polymerization of methacrylates usually depends on the structure of the ester groups. For example, in the polymerization of ethyl methacrylate (EMA) with n-C4H9Li in toluene at -78°C, there are at least two types of active species which give isotactic and syndiotactic-rich polymers, 5 while the polymerization of MMA under the same conditions gives isotactic-rich polymer only.In this article, anionic polymerization of EMA by t-C4H9MgBr in toluene was studied in detail, especially in regard to the stereo-*

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“…In particular, the achievement of stereocontrol during radical polymerization, which is widely used in industry for a variety of monomers, is a significant goal. [1][2][3][4][5] Recently, we found that Lewis acids catalytically affected stereochemistry during the radical polymerization of ␣-(alkoxymethyl)acrylates, 6 -9 methacrylates, 10 and acrylamides; 11 for example, N-isopropylacrylamide afforded a highly isotactic polymer (up to m ϭ 92%) in the presence of yttrium trifluoromethanesulfonate [triflate; Y(OTf) 3 ], whereas a slightly syndiotactic polymer was obtained in the absence of Lewis acids.…”

Section: Introductionmentioning

confidence: 99%