Polymerizations in the presence of seeds: 3. Emulsion polymerization of vinyl acetate in the presence of quartz powder

Hergeth, Wolf‐Dieter; Starre, Peter; Schmutzler, K.; Wartewig, S.

doi:10.1016/0032-3861(88)90064-x

Cited by 65 publications

(19 citation statements)

References 8 publications

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“…The morphology of nanocomposite latex may be possibly formed by the following mechanism: monomer molecules and surfactants can be adsorbed onto the surface of hydrophobic TPM‐modified nano‐silica, and surfactants act as micelles to ensure the polymerization take place around the nano‐silica 38–40. The smaller silica particles have higher surface energies and the distance between the centres of mass for two nano‐silica particles is always smaller than the Van der Vaals radius, so TPM‐modified silica with smaller diameter unavoidably exhibits a stronger tendency to aggregation, leading to more nano‐silica in latex particles in comparison with the larger nano‐silica particles.…”

Section: Resultsmentioning

confidence: 99%

Particle size and morphology of poly[styrene‐co‐(butyl acrylate)]/nano‐silica composite latex

You

et al. 2004

Polymer International

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Nanocomposite latex with nano‐silica of varying particle sizes was prepared via in situ polymerization and investigated by submicron particle size analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier‐transform infrared spectrometry (FTIR) and Raman spectrometry. It was found that nanocomposite latex exhibited a core–shell structure with nano‐silica particles enwrapped, resulting in an increase in the latex particle size. The smaller the nano‐silica particles, the more were embedded in each latex particle. The increase in the particle size of latex depended not only on the particle size of nano‐silica, but also on the number of nano‐silica particles in each latex particle. Copyright © 2004 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Particle size and morphology of poly[styrene‐co‐(butyl acrylate)]/nano‐silica composite latex

You

et al. 2004

Polymer International

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“…In order to increase the φ S and φ f using our previously reported encapsulation strategy, it is important to realize what limits these parameters in the approach followed thus far. All polymerizations have been carried out using a starved monomer feed to an aqueous dispersion of Gibbsite (G) containing initiator and a fixed amount of anionic cooligomer (S), which was higher than that roughly corresponding to two times the isoelectric concentration (required for a stable Gibbsite dispersion) and lower than that corresponding to the critical micelle concentration (cmc), to avoid secondary nucleation . Within this concentration range of S, it was found that particle growth proceeded in similar ways irrespective of the concentration of S ([S]), but that colloidal instability occurred sooner at lower [S].…”

Section: Resultsmentioning

confidence: 99%

“…All polymerizations have been carried out using a starved monomer feed to an aqueous dispersion of Gibbsite (G) containing initiator and a fixed amount of anionic cooligomer (S), which was higher than that roughly corresponding to two times the isoelectric concentration (required for a stable Gibbsite dispersion) and lower than that corresponding to the critical micelle concentration (cmc), to avoid secondary nucleation. [27] Within this concentration range of S, it was found that particle growth proceeded in similar ways irrespective of the concentration of S ([S]), but that colloidal instability occurred sooner at lower [S]. Hence, a logical conclusion from this observation is that in order to reach higher polymer contents (per Gibbsite platelet) one needs to feed additional S in such a way that the cmc is not exceeded and the simplest way of doing this is by starting a feed of S just before the colloidal instability occurs.…”

Section: Methods Developmentmentioning

confidence: 99%

Design and Preparation of Highly Filled Water‐Borne Polymer–Gibbsite Nanocomposites

Loiko

Spoelstra

Herk

et al. 2017

Macro Reaction Engineering

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The discovery of a reversible additionfragmentation chain transfer (RAFT)-mediated encapsulation method for filler materials, [12] however, caused a significant shift in encapsulation strategy and many examples now exist in which this method was applied successfully. [13][14][15][16][17][18][19][20] We recently extended this method to an atom transfer radical polymerization (ATRP)-based method, [21] which only in the presence of a cross-linker led to encapsulated particles; [22] without cross-linker so-called "muffin-structures" were obtained. [21] Realizing that the charged, reactive, oligomers used in both the RAFT and ATRP approaches in first instance act as stabilizers for the initial clay dispersion and subsequently for the polymer particles, we then used the charged oligomers as unreactive surfactants in a conventional starved-feed emulsion polymerization. [21] This procedure for the encapsulation of unmodified Gibbsite platelets involves the adsorption of (an excess of) anionic cooligomers of butyl acrylate and acrylic acid unto the cationic Gibbsite surface, followed by a conventional starved feed emulsion polymerization and is schematically shown in Scheme 1. [23] A clear effect of cooligomer concentration on the colloidal stability was observed and, as expected, only a limiting amount of polymer per Gibbsite platelet could be stabilized before colloidal instability occurred. [23] The obtained solids content (φ S ) in these studies was therefore rather low (i.e., φ S = 17 wt%) and had a very low filler content (φ f ) of 0.4 wt%, [23] see Appendix B for the definitions of φ S and φ f . Higher solids and filler contents, however, would be desirable for practical applications.Polymer-clay nanocomposites with a solids content as high as 50 wt% have been reported in the literature, but most of them were obtained with a relatively low filler content (≤3 wt%); [3,6] only a limited number of publications were dedicated to the preparation of highly filled polymer-clay particles. [3,24,25] These studies indicated that the compounds used for hydrophobization of clay [3,24] and the size of the clay platelets [25] can affect the maximum filler content and that the use of larger amounts of clay platelets may result in less colloidal stability because of an increase in ionic strength of the water phase. [26] It has also been observed that the morphology of the resulting nanocomposites was affected by the filler amount. [24] Overall, it can safely be concluded that the synthesis of highly filled polymer-clay nanocomposites with a controlled morphology still remains a challenge. NanocompositesHighly filled, high solids content, water-borne polymer-Gibbsite nanocomposites are prepared with Gibbsite contents as high as 35 wt%. The polymerGibbsite nanocomposites are synthesised via conventional starved feed emulsion polymerization using negatively charged butyl acrylate-co-acrylic acid oligomers, which functioned as electrosteric stabilizers for the initial platelets and the subsequently formed latex particles. A simple ma...

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“…[9]). Condition 1 was experimentally verified using polymer latexes [9,10,11] and inorganic quartz powder filler particles as seeds [12]. Under these circumstances, additional experimental conditions for the formation of homogeneous polymeric shells around polymeric s~d s can be summarized as follows [11,13]: -use of water soluble initiator -monomer II addition under starved conditions -higher water solubility of monomer II than that of monomer I -incompatibility of the two polymers.…”

Section: R E S U L T S a N D Discussionmentioning

confidence: 99%

SAXS study of core-shell colloids

Beyer

Lebek

Hergeth

et al. 1990

Colloid & Polymer Sci

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Polymeric core-shell systems were produced by a two-stage emulsion polymerization technique under fixed conditions: i) monodisperse seed latex with a sufficiently high particle number; ii) starved monomer-II addition; iii) water-soluble initiator; iv) incompatibility of core and shell polymer. From electron micrographs, it is not possible to determine where the second polymer is located within these two-stage emulsion polymers. The internal structure of the particles can be detected by small-angle x-ray scattering. The results indicate that; i) the emulsion polymerization process takes place in a small surface layer region of the seed particles, and ii) a small interfacial layer exists between the core and shell polymer.

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Polymerizations in the presence of seeds: 3. Emulsion polymerization of vinyl acetate in the presence of quartz powder

Cited by 65 publications

References 8 publications

Particle size and morphology of poly[styrene‐co‐(butyl acrylate)]/nano‐silica composite latex

Particle size and morphology of poly[styrene‐co‐(butyl acrylate)]/nano‐silica composite latex

Design and Preparation of Highly Filled Water‐Borne Polymer–Gibbsite Nanocomposites

SAXS study of core-shell colloids

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