Papers by Keyword: Core-Shell Particle

Abstract: This study aims to describe the preparation and characterization of SiO₂/TiO₂ core-shell particles. In order to prepare the homogenous SiO₂/TiO₂ inorganic compounds by sol-gel process, SiO₂ particles were used as the core, AcAc served as a chelating agent to chelate with TTIP (which was used as the precursor to TiO₂), and PEG was added to stabilize the hydrolysis/condensation process. In addition, the ionic surfactant (SDS) and the nonionic surfactant (PVP) dispersed the core-shell particles. In order to improve the crystal structure, a high temperature was used to calcine the core-shell particles. The influence of various reaction parameters on the size, morphology and composition of the particles was also investigated. The properties of the particles were analyzed by electron microscopy, fourier transform infrared analysis, thermogravimetric analysis and powder X-ray diffraction.

Abstract: Coating a particle with another material to form a core-shell structured composite is often used in powder technology. Silica has widely been selected as the shell material due to its ease of fabrication, versatile surface functionality, physical and chemical stability. In this artilce, the proctective and modifying roles of silica shells in core-shell particles have been briefly reviewed.

Abstract: Fluoroacrylic copolymer latexes with core-shell structure were synthesized by free-radical emulsion copolymerization, using fluorine-containing acrylic monomer of dodecafluoroheptyl methacrylate (DFMA) and fluorine-free acrylic monomers. The chemical composition was characterized by Fourier transform infrared (FTIR) spectroscopy. The basic properties of the latexes including mainly hydrophobicity, chemical stability, chemicals-and corrosion-resistance were investigated. Significant improvement in the chemicals-and corrosion-resistance were observed for the fluorinated copolymer although only 5 wt% (based on the total monomers amount) of DFMA was copolymerized.

Abstract: Porous materials were prepared by sintering using C as place holder and SiO2 as based, mixed with paraffin. Then Organic-inorganic Core-shell Particles were made by crushed. With the help of XRD and SEM, on the 60°C Study on Sulfate-Corrosion Resistance of cement Mixed with Organic-inorganic Core-shell of Preparation. The Organic-inorganic Core-shell Particles made by accounted of C 15% and heat preservation 4h in 920°C were the best. The results showed that when the content of Organic-inorganic Core-shell Particles was 15%, the Sulfate-Corrosion Resistance reached the climax.

Abstract: Starve feed and semi-continuous seed emulsion polymerization were used to control the morphology of core shell latex particles with a vinyl acetate (VAc)/vinyl ester of versatic acid 10(VeoVa10) copolymer core surrounded by a poly(glycidyl methacrylate) (PGMA) shell. Pure core and core-shell structures were confirmed by TEM. The results suggest that core-shell morphology of the two stage emulsion was favoured by higher concentration of emulsifier in the seed latex: the particle size distribution of core-shell latex was broader than that of the core latex, and the average particle size of core-shell latex was larger than that of the core latex. The core-shell structure was not produced using seed emulsion with emulsifier concentration at or below the critical micelle concentration. The core shell emulsion containing epoxy functional group with added ethylene diamine showed an abrupt increase in dynamic shear moduli, G' and G'' and complex viscosity η* (several orders of magnitude) at about 35oC, during temperature ramps, over a wide range of angular frequencies. The time ramps showed that the crosslinking reaction did not occur at 15oC for the core-shell emulsion/amine system. The time for gel formation decreased with increase in temperature.

Abstract: Hybridization is a promising method for core/shell particles by a mechanical shock process involving dry blending and dry impact blending. In this paper, hybridization was used to prepare TiB2/Ni ceramics/metal and TiB2/Al2O3 ceramics/ceramics core/shell particles. The mechanism of the formation and the features of the core/shell particles were analyzed. The nano- Al2O3 particles can be coated on the surface of micron TiB2 particles directly by hybridization, The sub-micron Al2O3 particles can be coated on the surface of micron TiB2 particles, only with the introducing of PE-wax as transition layer. The mechanical properties of cermet sintered from TiB2/Ni core/shell ceramics/metal particles were compared with that from TiB2/Ni blended particles.

Abstract: A novel Ni-YSZ anode with interpenetrating phase composite (IPC) structure was developed using NiO-YSZ core-shell composite powder and evaluated in terms of microstructure, electrical conductivity, thermal expansion and flexural strength. In comparison to conventional anode, the anodic performance of IPC anode appeared to be more desirable for improving structural reliability of SOFC unit cells and stacks. This study reveals that the anodic performance of IPC anode can be readily tailored by controlling core-shell composite powder particles.

Abstract: Coating process is attracting more and more attention in the preparation of composite materials mainly due to its predominance in the improvement of the uniformity for different phases. The formation of nanosize alumina shells on the aluminum core particles by a wet-chemical based route was investigated and the composite particles were characterized using TG/DSC, XRD, SEM, TEM, XPS. An enhancement of cermet properties can be expected by using these coated particles as initial powders.