火焰法二氧化硅团聚体的高压液体分散与破碎

High-pressure liquid dispersion and fragmentation of flame-made silica agglomerates.

作者信息

Wengeler Robert, Teleki Alexandra, Vetter Markus, Pratsinis Sotiris E, Nirschl Hermann

机构信息

Institute for Mechanical Process Engineering and Mechanics, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany.

出版信息

Langmuir. 2006 May 23;22(11):4928-35. doi: 10.1021/la053283n.

DOI:10.1021/la053283n

PMID:16700577

Abstract

The influence of primary particle diameter and the degree of agglomeration of flame-made silica agglomerate suspensions in aqueous solutions is studied by high-pressure dispersion (up to 1500 bar) through a nozzle with a 125 microm inner diameter. These particles were produced (4-15 g/h) by oxidation of hexamethyldisiloxane (HMDSO) in a coflow diffusion flame reactor. Their average primary particle size (10-50 nm) and degree of agglomeration were controlled 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 yield hard agglomerate sizes in the range of 100-180 nm, as characterized by dynamic light scattering. Soft agglomerates exhibited decreasing light scattering diameters with increasing dispersion pressure, while hard agglomerates were insensitive.

摘要

通过内径为125微米的喷嘴进行高达1500巴的高压分散，研究了火焰法制备的二氧化硅团聚体悬浮液在水溶液中的初级粒径和团聚程度的影响。这些颗粒是在并流扩散火焰反应器中通过六甲基二硅氧烷（HMDSO）氧化产生的（4-15克/小时）。通过改变氧气和前驱体流速来控制它们的平均初级粒径（10-50纳米）和团聚程度。通过氮气吸附、电子显微镜和小角X射线散射对颗粒进行表征。流体动力应力会破坏软团聚体，并产生尺寸在100-180纳米范围内的硬团聚体，这通过动态光散射来表征。软团聚体的光散射直径随着分散压力的增加而减小，而硬团聚体则不敏感。