Impact of particle size and surface charge density on redispersibility of spray-dried powders

Hong, Liang; Chen, Liang; Ladika, Mladen; Li, Yongfu; Kim-Habermehl, Linda; Bergman, Roger

doi:10.1016/j.colsurfa.2014.07.015

Cited by 8 publications

(2 citation statements)

References 29 publications

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“…Since it would not be possible to spray-dry a polymer with such a low Tg, a harder shell is grown around the soft core to limit particles coalescence and form RPPs. Indeed, core-shell morphologies were intensively studied in the literature and found application in various research areas, including limitation of the particles interpenetration upon drying, controlled release of encapsulated active ingredients, and tuning of the liquid-liquid interfaces [28,29,30,31,32,33]. In particular, for the preparation of RPPs, the core-shell morphology can improve the polymer spray-ability and its redispersion, without affecting the film forming and crack-bridging properties and without further addition of expensive additives [24,34,35,36].…”

Section: Introductionmentioning

confidence: 99%

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

et al. 2018

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Redispersible powders based on soft core-hard shell polymer particles can be used as additives in polymer-cement mortars. The role of this morphology on the spray-drying production of these powders and on the crack-bridging properties of the corresponding cement-based membranes is investigated. Different polymer latexes at high solid content with varied core-shell ratio, shell thickness and chemical composition (hardness) were prepared from styrene and 2-ethylhexyl acrylate monomers via semi-batch emulsion polymerization. The latexes were characterized in terms of size, composition, and glass transition temperature (T g ), and spray-dried to obtain redispersible polymer powders (RPPs) using poly (vinyl alcohol) and limestone powder as anti-caking agents. The polymer powders were mixed with a mortar mixture and redispersed in water to produce cement-based membranes, which were tested for crack-bridging properties at different temperatures. The results showed that it was not possible to spray-dry a dispersion of homogeneous polymer particles with T g of −25 ∘ C, unless these particles are protected by much harder (high T g ) shell. In particular, it was observed that a thicker shell improved the spray-ability, but lowered the crack-bridging properties of the produced membrane. A trade-off between these two was revealed to be the key for the optimal design of the polymer nanoparticles, as proven by the systematic study of the core-shell morphology reported in this work. The best compromise was shown to consist of particles larger than 300 nm, shell thickness of about 5 nm, and core-shell ratio of 97%, with styrene content in the shell not larger than 80% to avoid excessive hydrophobicity.

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Section: Introductionmentioning

confidence: 99%

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

et al. 2018

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“…It was reported that SBR retards the early hydration reaction of cement in SBR‐modified cement pastes but has no effect on the hydration degree at long curing age . SA latex is one commonly used polymer latexes in construction industry because of its superior properties such like flexibility and water‐proofing property. By using model SA latexes, our previous studies have concluded that the retardation effect of SA latexes on cement hydration is strongly related to the surface properties of the colloidal particles in the latex .…”

Section: Introductionmentioning

confidence: 99%

Effect of polymer latexes with varied glass transition temperature on cement hydration

Kong

Zhang

et al. 2017

J of Applied Polymer Sci

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Influence of styrene‐acrylate latexes with varied glass transition temperature (Tg) on cement hydration was studied and the mechanism was analyzed. Results show that polymer latexes with varied Tg retard cement hydration to different extents. Specifically, low Tg polymer shows stronger retardation effect than the high Tg polymer. Despite similar surface charges, colloidal particles with lower Tg exhibit higher affinity to surface of cement grains than the high Tg polymer, indicated by the higher adsorption amount and denser covering layer. The low Tg polymer experiences particle packing, deforming, and film forming processes along with the consumption of water during cement hydration, which eventually produces a covering layer of polymer surrounding cement grains. However, for the high Tg polymer, film forming process is absent. Consequently, the higher adsorption amount and the film‐formation process along with cement hydration are the two reasons for the stronger retardation effect of the low Tg polymer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45264.

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Recent trends and applications in the research and development activities of redispersible powder: a vision of twenty-first century

Tarannum

Pooja

2021

Polym. Bull.

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Impact of particle size and surface charge density on redispersibility of spray-dried powders

Cited by 8 publications

References 29 publications

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

Effect of polymer latexes with varied glass transition temperature on cement hydration

Recent trends and applications in the research and development activities of redispersible powder: a vision of twenty-first century

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