The preparation of surface modified silica particles by two step process

초록

Surface modified silica particles were prepared by two-step (acid-base) process in an aqueous solution with organoalkoxysilanes, such as methyltrimethoxysilane (MTMS), vinyltrimethoxysilane (VTMS), or phenyltrimethoxysilane (PTMS). The hydrolysis and condensation rates of organoalkoxysilanes could be elucidated from this system. The kinetic data obtained by measuring the mixing time (hydrolysis) and the turbid time (condensation) indicated that the hydrolysis rate in the acid catalyzed condition followed a usual order of MTMS>VTMS> PTMS and the condensation rate in the base catalyzed condition followed a reverse order of PTMS>VTMS>MTMS. These orders in the rate of hydrolysis and condensation could be rationalized by two opposing factors, the steric effect and inductive effect. Furthermore, the formation and growth mechanism related with the condensation were demonstrated.