作者: Kwan Wuk Park, Jin Seok Lee, Hee Jin Lim, Sung Churl Choi
摘要: Bi-based glass pastes were prepared in the mixed organic solvents (α-terpineol and texanol)
with different kinds and concentrations of organic dispersant such as fish oil , phosphate ester and
poly methyl methacrylate (PMMA). The rheological stability of glass pastes was characterized by
using a rheometer and adsorption behavior of organic additives for the glass powders was carried out
by using a thermal gravimetric analyzer (TGA).The Bi-based glass pastes exhibited the most stable
rheological behavior at an addition of phosphate ester of 0.5 in mass %, due to the steric repulsive
force acting on the surface of glass powers with adsorbing the organic additives. This study allowed
significant delay of the sedimentation time and suppressed generation of micropores during practical
forming process by a screen printing method.
355
作者: Gang Qiang Geng, Xin Jun Liu, Gong Xun Bian
摘要: With silane coupling agent on silica aerogels by modification pretreatment, we obtained the core-shell structure of polystyrene grafted mesoporous silica aerogels through the dispersion polymerization process. By Orthogonal design method to study the effects of the system, results showed that: the greatest influence of the system component on the conversion rates was the mass ratio of silica aerogels and styrene and the best parameter value was obtained. By analyzing the effects of the initiator and dispersion technology, we obtained a core-shell structure whose stable coating was 70% with organic initiator AIBN as initiator after a unique ultrasound technique. Through TEM the core-shell structure was characterized.
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作者: Biao Yang, Sheng Wang, Guo Zhi Xu, Fei Xin
摘要: The nano-SiO2/polyethylene glycol (PEG) dispersion system was prepared by centrifugal mixing, and its rheological properties were investigated. The results showed the revolution and rotation speed during the centrifugal mixing have a significant effect on the rheological properties of SiO2/PEG system. When the revolution speed of the centrifugal mixer was fixed at a high speed of 1200rpm, the shear thickening effect of SiO2/PEG was gradually increased with the decrease of rotation speed, and the maximum viscosity (η) of 12340 mPa•s appeared at the rotation speed of 200 rpm. At the low revolution speed of 700 rpm, the increase of the rotation speed significantly enhanced the shear thickening effect. When the rotation speed was 700rpm, the maximum viscosity was up to 86130mPa s. In steady state experiments, the systems show a shear-thinning property under low shear rate. When the shear rate exceeded a critical value (γ= 24.92 s-1), the viscosity first increased, and then decreased sharply. In the dynamic experiments, with the increase of angular frequency (ω), the loss modulus (G″) also increased and the systems behaved as a shear-thickening fluid.
586
作者: Dan Li, Zhou Lan Yin, Qi Yuan Chen
摘要: The influences of three kinds of polyethylene glycol (PEG), namely PEG-200, PEG-1000 and PEG-20000, on the dispersion stability of pyrite powder in aqueous solution were investigated by spectrophotometry. The results indicated that the stability of pyrite powder dispersed in aqueous solution was remarkably dependent upon the molecular weight and content of PEG, pH value of suspension, and ultrasonication power. Among three kinds of polyethylene glycol, PEG-20000 was the most effective additive to improve the dispersion stability and wettability of pyrite powder in water. When 8% PEG-20000 was employed as the dispersant, the best dispersion stability of pyrite powder in aqueous solution could be obtained under the conditions of pH at 5-6 and 100-W ultrasonication power. The FTIR spectroscopic analysis showed that the adsorption between the polyethylene glycol and pyrite ore powder was formed by hydrogen bonding. The adsorption of polyethylene glycol onto the surface of pyrite powder via hydrogen bonding provided a high degree of steric stabilization, which effectively prohibited the aggregation of pyrite powder, and thus the dispersion stability of as-formed aqueous suspension was promoted.
349
作者: Hui Qin Cao, Ji Luo, Wei Wei Yang
摘要: In order to develop a high-strength aluminum alloy, alumina dispersion strengthened aluminum alloy was prepared by high energy ball milling on 2024 aluminum alloy powder in ethanol. The microstructure, particle size and distribution of the Al2O3 particles in the alloy were analyzed by FE-SEM; the mechanical properties were investigated. Results showed that alumina dispersion strengthened aluminum alloy was prepared successfully by high energy ball milling, the Al2O3 particles of several tens of nm in diameter were homogeneously distributed in the matrix grain and the spatial distance between particles was about 50-100nm. The yield strength and elongation of alumina oxide dispersion strengthened aluminum alloy were 489MPa and 7.9%.
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