| 摘要 |
Spherical silica particles (I) are produced by hydrolytic polycondensation of tetraalkoxysilanes (II) in aq. alcoholic ammonia. The process involves the initial prodn. of a sol. of prim. particles, followed by the addn. of further (II) in a continuous and controlled way, to obtain highly-monodisperse, non-porous particles of mean dia. 0.05-10 microns with a standard deviation of not more than 5%. (I) contains covalently-bound organic gps. in the matrix, which are normally used for the modification of silica gel. The polycondensation is carried out at 35-75 (pref. 40-65) deg.C; (II) is derived from 1-3C alcohol (esp. EtOH); 0.1-100 (pref. 1-30) wt.% of (II) is replaced with organo-tri-alkoxysilane. |
