Poly(ethylene oxide) macromonomers. 7. Micellar polymerization in water

Ito, Koichi; Tanaka, Kazuo; Tanaka, Hiroshige; Imai, Genji; Kawaguchi, Seigou; Itsuno, Shinichi

doi:10.1021/ma00009a035

Cited by 195 publications

(158 citation statements)

References 2 publications

(2 reference statements)

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“…20 Thus the degree of polymerization as determined by SEC (Figure 1a) was very close to that predicted by the molar ratio of EO to the initiator charged, i.e., n = 1 + [EO] o /[E 1 K] o , and the molecular weight distribution was narrow with M w /M n = 1.12. In 1 H NMR spectrum (Figure 2a), the intensity ratio of the methoxy (a) and oxyethylene (b) peaks at δ3.4 and δ3.7, respectively, was also very close to that expected, i.e., 3/4n, supporting the incorporation of the methoxy end-group as an initiator fragment in each polymer chain.…”

Section: Preparation Of Eo-so Block Macromonomerssupporting

confidence: 70%

Syntheses of Poly(ethylene oxide-b-styrene oxide) Macromonomers and Their Application to Emulsion and Dispersion Copolymerizations with Styrene

Imai

Kawaguchi

Ito

2003

Polym J

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ABSTRACT:Poly(ethylene oxide-b-styrene oxide) macromonomers carrying p-vinylbenzyl ether end group were prepared by sequential anionic polymerization of ethylene oxide and styrene oxide with potassium 2-methoxyethoxide, followed by reaction with p-vinylbenzyl bromide to the end-group functionality up to 85%. The macromonomers have been successfully applied to emulsion and dispersion copolymerizations with styrene to afford monodisperse polymeric microsheres in water and in methanol-water (9/1 v/v) mixture, respectively. Incorporation of the macromonomer into the particle is more effective, so resulting in smaller particle size, in the emulsion than in the dispersion system. The particle size in the latter system decreased with the macromonomer concentration in accord with a previously proposed power-law theory and with the chain length of the styrene oxide block.KEY WORDS Macromonomers / Ethylene Oxide / Styrene Oxide / Block / p-Vinylbenzyl EndGroup / Emulsion / Dispersion / Amphiphilic macromonomers find increasing concern in view of their potential use for preparation of polymeric microspheres of submicron to micron size by emulsion and dispersion copolymerizations with a hydrophobic monomer in water and alcoholic media, respectively, without conventional surfactants ('soapfree'). They are usually composed of hydrophilic polymer chains (tails) and the hydrophobic polymerizable end groups (heads), which copolymerize in situ with a substrate hydrophobic monomer to afford graft copolymers. So they serve as effective stabilizers firmly (covalently) attached on the particle surfaces in such a manner that the hydrophobic heads act as anchors while the hydrophilic tails work as steric stabilizers against flocculation. So far a lot of macromonomers have been reported for design of various kinds of polymer microspheres. [1][2][3][4][5] In design of such macromonomers, considerable attention has been paid for control of hydrophiliclyophilic balance (HLB). To our experience, properly hydrophobically enhanced heads as well as properly long hydrophilic tails appear to be important in fine size control and stability of the microspheres to be obtained. In case of poly(ethylene oxide) (PEO) macromonomers with styryl or methacrylate end groups, introduction of some alkylene spacers 6-9 has been successful in this regard. Also interesting is the amphiphilic macromonomer of block copolymer type, 10-14 in which hydrophilic segments are connected through hydrophobic segments to polymerizable end groups. Examples include block macromonomers from poly(2-oxazoline)s, 10, 11 PEO-b-polystyrene (PSt), 12 PEO-bpoly(butylene oxide), In extension of our PEO macromonomer studies, in this paper we discuss preparation of PEO-bpoly(styrene oxide) (PSO) macromonomers with pvinylbenzyl (VB) end groups for use in emulsion and dispersion copolymerization with styrene. Here we expected that PSO segments with VB would provide good balance with the hydrophilic PEO chains for particle size control. The surface properties of PEO-b-PSO block copolymer...

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Section: Preparation Of Eo-so Block Macromonomerssupporting

confidence: 70%

Syntheses of Poly(ethylene oxide-b-styrene oxide) Macromonomers and Their Application to Emulsion and Dispersion Copolymerizations with Styrene

Imai

Kawaguchi

Ito

2003

Polym J

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“…Therefore, they behave as amphiphiles and their solubility and behavior depend on the chemical nature of the solvent. Ito et al [14][15][16] took advantage of the amphiphilic character of monofunctional PEO macromonomers to polymerize them, by free radical polymerization processes in water, to high yields. They demonstrated that free radical homopolymerization (or co-polymerization) of PEO macromonomers differs from that of low molar mass monomers in their structure and propagation rate.…”

Section: Peo Macromonomer Polymerization 321 Preliminary Remark αmentioning

confidence: 99%

From free radical to atom transfer radical polymerization of poly(ethylene oxide) macromonomers in nanostructured media

Buathong¹,

Peruch²,

Isel³

et al. 2004

Designed Monomers and Polymers

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Abstract-Polymerization of bifunctional α,ω-methacryloyloxypoly(ethylene oxide) (PEO) macromonomers was performed in water (or in organic solvents) via free radical or Atom Transfer Radical Polymerization (ATRP). Rapid cross-linking was observed when the reaction was conducted at 60 • C via classical free radical polymerization with potassium peroxodisulfate as initiator. ATRP also yielded hydrogels, but the system was much more complex. In both cases, the characteristics of the resulting hydrogels (amount of extractable material, equilibrium swelling degree and uniaxial compression modulus) were studied. They depend on several parameters (precursor molar mass, macromonomer concentration, polymerization time and nature of the initiating system). The hydrogels obtained by ATRP are characterized by higher amounts of extractable materials and exhibit rather poor mechanical properties. Regardless of the polymerization process (free radical or ATRP), far better results were obtained when the reaction was conducted in water. In fact, in aqueous media, the hydrophobic end-standing polymerizable methacrylic units of the macromonomers self-organize, after which gel formation takes place much more rapidly.

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“…22 In Table I are listed characteristics of the graft copolymer, poly(styrene-co-C 1 -EO 18 -(CH 2 ) 7 -S) and homopolymers, poly(C 1 -EO n -(CH 2 ) m -S) used in this study. These polymers were prepared by micellar (co-)polymerization of the corresponding macromonomers in water at 60 • C with 4,4 -azobis(4-cyanovaleric acid), AVA, as an initiator, followed by fractionation to remove the macromonomer unreacted.…”

Section: Methodsmentioning

confidence: 99%

“…From light scattering experiments, they clearly demonstrated that the graft copolymers form micelles with unimolecularly organized structures in a selective solvent for the grafted chain but in the solvent for backbone they form flower- like micelle and/or flower-connecting micelle. 21 In the previous papers, [22][23][24] we reported that micellar, organized homopolymerization of amphiphilic ω-methoxy-α-p-styrylalkyl-poly(ethylene oxide) (PEO) macromonomers (1) (C 1 -EO n -(CH 2 ) m -S) unusually rapidly proceeds to quantitatively afford regular combshaped polymers with high degree of polymerization. Quite recently, we have also reported that micellar copolymerization of C 1 -EO 18 -(CH 2 ) 7 -S with a limited amount of styrene solubilized therein proceeds in the manner of a pseudo-living radical copolymerization with highly limited terminations between compartmentalized (isolated) propagating radicals.…”

mentioning

confidence: 99%

Fluorescence Probe and Scanning Force Microscopic Studies of Water Soluble Comb-Shaped Copolymers Consisting of a Hydrophobic Poly(p-alkylstyrene) Main Chainand Hydrophilic Poly(ethylene oxide) Grafted Chains

Kawaguchi

Maniruzzaman

Katsuragi

et al. 2002

Polym J

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ABSTRACT:Solution properties of regular amphiphilic comb-shaped polymers have been studied in water by means of fluorescence technique using pyrene as a probe, dynamic light scattering, 1 H NMR, and scanning force microscopy (SFM). They consist of a hydrophobic poly(p-alkylstyrene) as a main chain and hydrophilic poly(ethylene oxide) (PEO) chains as a graft chain. Two types of the comb-shaped polymers have been explored, which were prepared by micellar, organized homopolymerization of amphiphilic PEO macromonomers (1) (C 1 -EO n -(CH 2 ) m -S, with a p-alkylstyrene ((CH 2 ) m -S) end group, with m = 1 and 7, and a PEO chain with n = 18, 46, 115, and 469) and by copolymerization of C 1 -EO 18 -(CH 2 ) 7 -S with styrene in water, respectively. Partitioning, I 1 /I 3 , and excimer formation of pyrene were studied for their dilute aqueous solutions, and rationalized with the local concentration and structure of the comb-shaped polymers. Hydrophobic pyrene molecules were principally dissolved into the vicinity of the hydrophobic p-heptylstyrene main chain of the comb-shaped polymers. The nature of the hydrophobic main chain of poly(styrene-co-C 1 -EO 18 -(CH 2 ) 7 -S) was found to be essentially similar to that of a series of poly(C 1 -EO n -(CH 2 ) m -S). Direct observation of single macromolecule of poly(C 1 -EO 46 -(CH 2 ) 7 -S) by SFM revealed a high molecular weight, cylindrical brush-like conformation with ca. 12.8 nm in thickness. In contrast, small fine particles were observed for poly(styrene-co-C 1 -EO 18 -(CH 2 ) 7 -S), suggesting the formation of a unimolecular micelle in water.KEY WORDS Poly(ethylene oxide) Macromonomer / Amphiphilic Graft Copolymer / Combshaped Polymer / Scanning Force Microscopy / Branched Polymer / Pyrene / Fluorescence Spectroscopy / Unimolecular Micelle / Polymacromonomer / Micellization of amphiphilic polymers in a selective solvent has been of continuing interest over the past two decades. This is not only because of their biological relevance but also because of their usefulness for such industrial applications as paints, coatings, cosmetics, inks, and oil recovery.

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Poly(ethylene oxide) macromonomers. 7. Micellar polymerization in water

Cited by 195 publications

References 2 publications

Syntheses of Poly(ethylene oxide-b-styrene oxide) Macromonomers and Their Application to Emulsion and Dispersion Copolymerizations with Styrene

Syntheses of Poly(ethylene oxide-b-styrene oxide) Macromonomers and Their Application to Emulsion and Dispersion Copolymerizations with Styrene

From free radical to atom transfer radical polymerization of poly(ethylene oxide) macromonomers in nanostructured media

Fluorescence Probe and Scanning Force Microscopic Studies of Water Soluble Comb-Shaped Copolymers Consisting of a Hydrophobic Poly(p-alkylstyrene) Main Chainand Hydrophilic Poly(ethylene oxide) Grafted Chains

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