Formation of colloidal PMMA particles via free radical and group transfer dispersion polymerization of methylmethacrylate and methylmethacrylate/ethyleneglycoldimethacrylate

Hölderle, Matthias; Mülhaupt, Rolf

doi:10.1002/actp.1995.010460303

Cited by 6 publications

(8 citation statements)

References 13 publications

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“…The functionalized PMMA microgels were prepared by radical copolymerization of the compounds as described previously by Hölderle et al A cross-linking agent of 5 mol % ethyleneglycoldimethacrylate was incorporated. Different diameters were obtained by varying the dispersant concentration in the reaction mixture.…”

Section: Methodsmentioning

confidence: 99%

Meso- and Microscopic Behavior of Spherical Polymer Particles Assembling at the Air−Water Interface

Wolert¹,

Setz²,

Underhill³

et al. 2001

Langmuir

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Using the Langmuir Blodgett (LB) technique, monolayers of spherical polymer particles were investigated at the air-water interface. In this study, LB methods were used to examine particle interactions, packing, morphology, and viscosity of polymer films. Films composed of polymer microgels (diameters of 113-427 nm) having a block-copolymer dispersant were investigated through isotherm, atomic force microscopy imaging, and two-dimensional (2D) viscosity studies. During monolayer formation, the effect of the dispersant and particle size on the behavior of the isotherms was examined. The contact cross-sectional area of the isotherms for these spheres was compared to the ideal hexagonal close packing (hcp) model. Initial investigations concerning the flow properties of the particles in 2D slurries were also performed. In addition, spherical hyperbranched polymer particles (≈60 nm) with and without a modified hydrophilic surface were also studied using isotherm and hysteresis experiments and the hcp model. Both of these studies may show the influence of surface composition and particle size on the interaction of polymer particles at the airwater interface.

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Section: Methodsmentioning

confidence: 99%

Meso- and Microscopic Behavior of Spherical Polymer Particles Assembling at the Air−Water Interface

Wolert¹,

Setz²,

Underhill³

et al. 2001

Langmuir

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“…32 Holderle and Mulhaupt even used pS-b-EP to stabilize a pMMA dispersion in hydrocarbon solvents. 33 Therefore, pS-b-EP seemed suitable for the steric stabilization of pS-particle-covered droplets. It is shown in this article that the Pickering emulsion droplets with the adsorbed pS-b-EP are stable both against coalescence and against aggregation with other droplets and can, therefore, be efficiently processed into microcapsules.…”

Section: Introductionmentioning

confidence: 99%

“…Awan et al used this type of block copolymers as a polymeric stabilizer for anionic dispersion polymerization of styrene in hexane . Holderle and Mulhaupt even used pS- b -EP to stabilize a pMMA dispersion in hydrocarbon solvents . Therefore, pS- b -EP seemed suitable for the steric stabilization of pS-particle-covered droplets.…”

Section: Introductionmentioning

confidence: 99%

Steric Stabilization of Pickering Emulsions for the Efficient Synthesis of Polymeric Microcapsules

2010

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It is commonly known that Pickering emulsions are extremely stable against coalescence and are, therefore, potentially interesting for the synthesis of new materials, such as colloidosomes, microcapsules, composite particles, foams, and so on. However, for the efficient synthesis of such materials, one also has to consider the colloidal stability against aggregation, which is often neglected. In this study, it is demonstrated that steric stabilization is provided to Pickering emulsion droplets by the adsorption of poly(styrene-block-ethylene-co-propylene) (pS-b-EP) and that it is a requirement for the efficient synthesis of polymeric microcapsules. Monodisperse polystyrene particles of 648 nm are synthesized by soap-free emulsion polymerization. A model Pickering emulsion is then formed by the addition of sodium chloride at a critical concentration of 325 mM and mixing it with either heptane or decane. Subsequently, pS-b-EP is added to the Pickering emulsion to provide steric stabilization. Size exclusion chromatography is used to prove and quantify the adsorption of pS-b-EP onto the Pickering emulsion droplets. A maximum surface coverage of 1.3 mg/m(2) is obtained after 2 h, which is approximately one-third of the adsorption on a pure pS surface. We believe that the presence of polar sulfate groups on the particle, which initially stabilized the particle in water, reduces the adsorption of pS-b-EP. Microcapsules are formed by heating the Pickering emulsion above the glass-transition temperature of the particles. Significant aggregation is observed, if no pS-b-EP is used. The adsorption of pS-b-EP provides steric stabilization to the Pickering emulsion droplets, reduces aggregation significantly, and ultimately leads to the successful and efficient synthesis of pS microcapsules.

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“…Lastly, cross-linked polymer microparticles can be obtained by non-aqueous dispersion polymerization. [6,7,18,27,32] The solvent used in dispersion polymerization is a good solvent for monomers and initiator, and a poor one for the polymer formed during reaction. For this reason polymer microparticles have to be stabilized to prevent aggregation and macroscopic gelation.…”

Section: Introductionmentioning

confidence: 99%

(Meth)acrylic Cross-Linked Polymer Microparticles: Synthesis by Dispersion Polymerization and Particle Characterization

Valette¹,

Pascault²,

Magny³

2002

Macromol. Mater. Eng.

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Formation of colloidal PMMA particles via free radical and group transfer dispersion polymerization of methylmethacrylate and methylmethacrylate/ethyleneglycoldimethacrylate

Cited by 6 publications

References 13 publications

Meso- and Microscopic Behavior of Spherical Polymer Particles Assembling at the Air−Water Interface

Meso- and Microscopic Behavior of Spherical Polymer Particles Assembling at the Air−Water Interface

Steric Stabilization of Pickering Emulsions for the Efficient Synthesis of Polymeric Microcapsules

(Meth)acrylic Cross-Linked Polymer Microparticles: Synthesis by Dispersion Polymerization and Particle Characterization

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