A new way to control particle morphology in heterophase polymerizations

Tauer, Klaus; Riedelsberger, Kerstin; Deckwer, R.; Zimmermann, Arvid; Dautzenberg, H.; Thieme, Juergen

doi:10.1002/1521-3900(200004)155:1<95::aid-masy95>3.0.co;2-i

Cited by 12 publications

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“…However, the observation of multiple morphologies on SEM and TEM images and even different structures depending on the sample preparation conditions demands cautious interpretation and additional studies with other characterization techniques avoiding drying artifacts such as cryogenic electron microscopy [43] or even in situ techniques such as X-ray absorption microscopy. [44,45] An important result of this study is the first experimental proof of the possibility to change properties of polymer dispersions due to targeted modification of the electrical double layer by coions. This finding might be important for the development of special polymer dispersions for sensing applications as recently described in ref.…”

Section: Resultsmentioning

confidence: 84%

High Ionic Strength Promotes the Formation of Spherical Copolymer Particles

Weber

Unterlass

Tauer

2011

Macro Chemistry & Physics

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A comprehensive experimental study of thermally initiated styrene‐styrene sulfonate emulsion copolymerization in the presence of 15 different low‐molecular‐weight electrolytes clarifies the enormous influence of both the concentration and nature of the added salt on the outcome of the polymerization. The ionic strength (IS) has a direct influence on the styrene sulfonate content in the final copolymer and determines whether the physical state of the final reaction product is a solution or dispersion. Stable latexes have been obtained for IS as high as 18 M. Electron microscopy images show irregularly shaped clusters at low and spherical particles at high IS. The properties of the copolymer molecules and dispersion can be additionally modified by the chemical properties of the counter‐ and coions introduced with the salt.magnified image

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Section: Resultsmentioning

confidence: 84%

High Ionic Strength Promotes the Formation of Spherical Copolymer Particles

Weber

Unterlass

Tauer

2011

Macro Chemistry & Physics

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“…We are not the first group to observe the formation of particles with anomalous structures in the heterophase polymerization process. The formation of particles with similar morphology to the PS particles shown in Figure in the course of surfactant-free emulsion polymerization has been reported for many decades. − However, to the best of our knowledge, a synthesis of hollow PS microparticles with the described novel morphology using a simple one-step dispersion polymerization method without a template has not been reported previously.…”

Section: Resultsmentioning

confidence: 71%

One-Step Synthesis of Hollow Dimpled Polystyrene Microparticles by Dispersion Polymerization

et al. 2017

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The design and preparation of hollow nonspherical microparticles are of great significance for their potential applications, but the development of a facile synthetic method using only one production step remains a great challenge. In the current work, a new template-free method based on dispersion polymerization was successfully developed to produce anisotropic hollow polystyrene (PS) microparticles in a single step. In the synthesis, ammonium persulfate (APS) played a critical role in the formation and growth of highly uniform and stable hollow PS microparticles. By varying the concentration of APS and that of the stabilizer used, polyvinylpyrrolidone, we were able to control the average size of the PS particles and their degree of concavity. Based on our results and observations, a plausible mechanism for formation of these unusually shaped PS microparticles was proposed.

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“…Third, in former studies it was found that polystyrene and PEG phase separate with increasing conversion and during storage due to incompatibility. 13,29 Fourth, a higher PEG content was observed in the smaller size particle fractions in former investigations (cf. above and ref 11) despite that after fractionation of the polystyrene latexes prepared with PEGA200 by ultrafiltration all unreacted PEGA200 was removed.…”

Section: Resultsmentioning

confidence: 73%

“…Second, the oxygen content is only slightly higher in the cross-linked samples, but one might expect a much higher difference as PEGAM400 is bifunctional compared to PEGA400 and in two of eight samples (S1-SN and C5-P) is even the reverse order observed. Third, in former studies it was found that polystyrene and PEG phase separate with increasing conversion and during storage due to incompatibility. , Fourth, a higher PEG content was observed in the smaller size particle fractions in former investigations (cf. above and ref ) despite that after fractionation of the polystyrene latexes prepared with PEGA200 by ultrafiltration all unreacted PEGA200 was removed.…”

Section: Resultsmentioning

confidence: 90%

Reactive Poly(ethylene glycol)s in Aqueous Radical Heterophase Polymerization

Tauer

Yıldız

2003

Macromolecules

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A comprehensive study is presented of aqueous heterophase polymerization of styrene with two kinds of reactive poly(ethylene glycol)s, each with an average molecular weight of the poly(ethylene glycol) units of 400 g mol -1 : symmetrical poly(ethylene glycol)-azo-initiators with either terminal hydroxyl or styryl groups. Two kinds of stabilizers have been employed either sodium dodecyl sulfate or cetyltrimethylammonium bromide. Results are presented with regard to polymerization kinetics (reaction calorimetry), average particle sizes (dynamic light scattering), molecular weights (size exclusion chromatography), particle morphologies (transmission electron microscopy), swelling ratios (in water and tetrahydrofuran), and cross-linking density (analytical ultracentrifugation). These results reveal the exciting possibilities of reactive poly(ethylene glycol)s in heterophase polymerization.

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A new way to control particle morphology in heterophase polymerizations

Cited by 12 publications

References 0 publications

High Ionic Strength Promotes the Formation of Spherical Copolymer Particles

High Ionic Strength Promotes the Formation of Spherical Copolymer Particles

One-Step Synthesis of Hollow Dimpled Polystyrene Microparticles by Dispersion Polymerization

Reactive Poly(ethylene glycol)s in Aqueous Radical Heterophase Polymerization

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