| 摘要 |
Silica is rendered hydrophobic by a catalyst-free, in-situ process that includes contact with a hydrophobing agent under vacuum at elevated temperature for a time sufficient to replace adsorbed water in the silica with the hydrophobing agent. The resulting dispersion of hydrophobic silica in an inert, liquid, hydrophobic carrier medium is then subjected to high shear forces for a time sufficient to produce a homogeneous dispersion of hydrophobic silica particles in a defoaming composition.
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