High-Pressure Liquid Dispersion and Fragmentation of Flame-Made Silica Agglomerates

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• 作者：Robert Wengeler ; Alexandra Teleki ; Markus Vetter ; Sotiris E. Pratsinis ; and Hermann Nirschl
• 刊名：Langmuir
• 出版年：2006
• 出版时间：May 23, 2006
• 年：2006
• 卷：22
• 期：11
• 页码：4928 - 4935
• 全文大小：884K
• 年卷期：v.22,no.11(May 23, 2006)
• ISSN：1520-5827

文摘

The influence of primary particle diameter and the degree of agglomeration of flame-made silica agglomeratesuspensions in aqueous solutions is studied by high-pressure dispersion (up to 1500 bar) through a nozzle with a 125m inner diameter. These particles were produced (4-15 g/h) by oxidation of hexamethyldisiloxane (HMDSO) ina coflow diffusion flame reactor. Their average primary particle size (10-50 nm) and degree of agglomeration werecontrolled by varying the oxygen and precursor flow rates. The particles were characterized by nitrogen adsorption,electron microscopy, and small-angle X-ray scattering. Hydrodynamic stresses break up soft agglomerates and yieldhard agglomerate sizes in the range of 100-180 nm, as characterized by dynamic light scattering. Soft agglomeratesexhibited decreasing light scattering diameters with increasing dispersion pressure, while hard agglomerates wereinsensitive.