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The Processes for Stabilizing Suspensions for Ceramic Thermal Barrier Coatings (TBC)
Published in Navid Hosseinabadi, Hossein Ali Dehghanian, Suspension Plasma Spray Coating of Advanced Ceramics, 2022
Navid Hosseinabadi, Hossein Ali Dehghanian
The superficial charge of the particles, altered by the pH, can either increase or decrease polymer adsorption on the surface. The electrosteric mechanism yields good results for aqueous suspensions. Researchers have tested some of the most used dispersants for aqueous suspensions, namely ammonium polyacrylate, sodium polyacrylate, polyvinylpyrrolidone, and polyacrylic acid, and reported ammonium polyacrylate, which is a polyelectrolyte, resulted in the lowest viscosity suspension.
Polymer Adsorption at Oxide Surface
Published in Kunio Esumi, Polymer Interfaces and Emulsions, 2020
Another acrylic copolymer of dimethyl diallyl ammonium chloride and acrylic acid (PDMDAAC-AA) has been used for adsorption on SiO2 [44]. The polymer adsorption depends on the pH and the presence or absence of electrolyte. In order to estimate conformation of PDMDAC-AA adsorbed on SiO2 by the (ESR) technique, PDMDAC-AA has been partly spin labeled with 4-amino-2,2,6,6-tetramethylpiperidinoxy [45]. In pure water, the polymer adopts a relatively flat configuration, whereas in the presence of electrolyte, the configuration becomes increasingly more extended as the surface coverage increases. In the absence of the electrolyte, more polymer adsorbs on SiO2 at pH 3 than at pH 6.5.
Flow Micro-Calorimetry (FMC) Applied to the Study of Polymer Adsorption on Divided Matters
Published in Michel Nardin, Eugène Papirer, Powders and Fibers, 2006
R. Al-Akoum, C. Vaulot, M. Owczarek, Alain Vidal, Bassel Haidar
Polymer adsorption on particles is of high scientific and technological concern in a tremendous number of applications and fields where surfaces and interfaces are critical criterion. Material science and reinforcement, colloid stability and flocculation, pigments, inks, pharmaceutical, and cosmetic preparations are few of many concerned purposes. The segment density profile of the adsorbed chain and especially the extension of its loops far from the surface are determining factors in all of these applications. The conformational conduct of a macromolecule in the adsorbed state is a direct result of the chemical structure, concentration, molar masse, and distribution of the polymer and of the surface chemistry, surface energy, and morphology of the solid.
Improvement of Lignite Flocculation by Ultrasound Pre-treatment and Performance Optimization Using Box-Behnken Design
Published in International Journal of Coal Preparation and Utilization, 2023
Lignite is one of the low-quality coals that has a large reserve in the world. Ongoing mining methods in coal mining have sharply increased the proportion of fine low-grade coal. It becomes difficult to improve the quality of coal, which leads to energy loss and environmental problems. Although flotation is the most common method used for the treatment of fine coal, it has some disadvantages (Song and Valdivieso 1998). Flocculation, oil agglomeration, or selective flocculation techniques are used as alternatives to flotation in fine coal processing (Warren 1975). Flocculation is the formation of a physical bridge between grains under the influence of high molecular weight materials such as polyelectrolytes or starch. Polymer adsorption to solid surfaces depends on the properties of polymers, such as molecular weight, sequence of polymer, and distribution of functional groups. One of the general mechanisms of flocculation is polymer bridging. In the polymer bridging model, the polymer is adsorbed to the particle surfaces from different points, and when the particles collide with each other during mixing, they can connect each other through polymer chains from these points (Laskowski and Attia 1992).