Polymer-encased vesicles

Regen, Steven L.; Shin, Jae Sup; Yamaguchi, Kazuo

doi:10.1021/ja00320a043

Cited by 59 publications

(24 citation statements)

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“…If such ordered monomers are polymerized under the high gravity field, isotacticity can be dominated rather than syndiotacticity in the resultant polymer. This estimation is supported by the report of Regen et al 9 They reported that the isotacticity of poly(methacrylic acid) increased by highly-ordered media such as lipid bilayer membranes.…”

Section: Effect Of Initiator Concentrationsupporting

confidence: 75%

Enhancement of Isotacticity in Bulk Radical Polymerization of Poly(methyl methacrylate) under Strong Gravity Field

Nishihara

Teramoto

Sakurai

et al. 2003

Polym J

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KEY WORDSPoly(Methyl Methacrylate)(PMMA) / Centrifugation / Strong Gravity Field / Tacticity / 1 H NMR spectroscopy / Isotacticity / Stereoregular polymers are one of the most important materials in industry due to its thermostability, stiffness and chemical resistance. Stereoregular polymers have been prepared by polymerization with metal catalysts such as Ziegler-Natta catalysts. They have been extensively studied by the polymerization with Grignard reagents, alkylaluminum and alkyllithium. 1 On the other hand, control of stereoregularity without metal catalysts should be valuable. For this purpose, it has been reported the polymerizations of methacrylates having bulky side chains. 2 However, this idea provides limitation of chemical structures in monomers and then may be less applicable to extend.In this study, we aim to increase stereoregularity in free radical bulk polymerization of general-purpose monomers without special metal catalyst. Therefore, we focused on the polymerization under strong gravity field over 10 5 g although there has been a few reports under gravity field of 10 4 g level 3 and their research aims are not related to stereoregularity. 3,4 Fortunately, one of the authors has established the sedimentation theory under mega gravity field 5 and also developed the centrifugal apparatus generated over 10 6 g. 6 This gravity field can induce the sedimentation of metal atoms in solid-solution system alloy. 7 If monomers have a deviated center of gravity and are exposed to strong gravity field, the polymerization may proceed with molecular orientation of the monomers. In this study, methyl methacrylate was used as a monomer. The tacticity of the resultant poly(methyl methacrylate) (PMMA) was measured by 1 H NMR spectroscopy. † To whom correspondence should be addressed.

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Section: Effect Of Initiator Concentrationsupporting

confidence: 75%

Enhancement of Isotacticity in Bulk Radical Polymerization of Poly(methyl methacrylate) under Strong Gravity Field

Nishihara

Teramoto

Sakurai

et al. 2003

Polym J

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“…Polymerization in one‐ and two‐dimension confinement of vinyl monomers can give more highly isotatic or syndiotactic polymers (depending on monomer) than those in bulk or solution polymerization 11–16. Likewise, three‐dimension confinement of the monomer in the small volume of a microemulsion droplet should also influence the microstructure of the polymer formed therein, because one or few polymer chains per particle are produced in this process.…”

Section: Introductionmentioning

confidence: 99%

Narrow size‐distribution poly(methyl methacrylate) nanoparticles made by semicontinuous heterophase polymerization

Aguilar

Rabelero

Nuño‐Donlucas

et al. 2010

J of Applied Polymer Sci

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The effect of surfactant (sodium dodecyl sulfate) concentration on particle size, molar masses, glass transition, and tacticity of poly(methyl methacrylate) (PMMA) nanoparticles synthesized by semicontinuous heterophase polymerization under monomer-starved condition at constant monomer feeding rate is reported. Starved conditions are confirmed by the low amount of residual monomer throughout the reaction and by the fact that the instantaneous polymerization rate is similar to the feeding rate of monomer. Under these conditions, polymer particles in the nanometer range (20-30 nm) were obtained with narrow size distribution (1.07 < D w /D n < 1.18), depending of surfactant concentration. Final particle size diminishes as the surfactant concentration is increased. Glass transition temperatures and syndiotactic content (54%-59%) of the produced polymers are substantially higher than those reported for commercial and bulkmade PMMA. Molar masses are much lower than those expected from termination by chain transfer to monomer, which is the typical termination mechanism in 0-1 emulsion and microemulsion polymerization of this monomer.

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“…In order to enhance the stability of the bilayer structure, polymerizable amphiphiles have been reported [8][9][10][11]. However, there have been few studies on morphological and mechanical properties of concentrated aqueous systems of these amphiphiles [12,13].…”

Section: Introductionmentioning

confidence: 99%

Morphology and viscoelasticity of bilayer aqueous colloids of low-molecular and macromolecular amphiphiles

Matsumoto

Heiuchi

Horie

1989

Colloid & Polymer Sci

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Aqueous colloids of didodecytdimethylammonium bromide (DMA), allylbis[2-(dodecanoyloxycarbonyl)ethyl] methylammonium bromide (ADM) and polymer of ADM (PADM) were employed for morphological and rheological studies.The polymerization was carried out by irradiation of UV-light for the monomeric colloid. Weight average molecular weight of the polymer is about 16.3 x 104.Diameters of vesicles at critical micelle (aggregate) concentration were 8 -10 nm in the aqueous colloids of DMA, ADM and PADM. Various bilayer textures which were dependent upon the concentration and the temperature could be found in these amphiphiles. In particular, the bilayer textures were full in variety in the PADM system.Rheological properties of the aqueous colloids of these amphiphiles depended strongly upon the bilayer textures.

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Polymer-encased vesicles

Cited by 59 publications

References 0 publications

Enhancement of Isotacticity in Bulk Radical Polymerization of Poly(methyl methacrylate) under Strong Gravity Field

Enhancement of Isotacticity in Bulk Radical Polymerization of Poly(methyl methacrylate) under Strong Gravity Field

Narrow size‐distribution poly(methyl methacrylate) nanoparticles made by semicontinuous heterophase polymerization

Morphology and viscoelasticity of bilayer aqueous colloids of low-molecular and macromolecular amphiphiles

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