Characterization of physicochemical properties of the inorganic components in the „core-shell”
-structured in polymer mixtures. Part II. The systems obtain pyrogenic silica
Polimery 2002, No 3, 201
Wet impregnation of pyrogenic silica (Aerosil 200 and Aerosil 300) with aqueous solutions of zinc salts [Zn(NO3)2, Zn(CH3COO)2, Zn(NH3)4(NO3)2 and zinc complexes with EDTA, ethylene diamine and diethyl triamine] was used to obtain a new type of dispersoids with „core-shell” (ZnO/SiO2 systems) structure, containing 1—20% ZnO by weight. Physicochemical properties of ZnO/SiO2 systems were determined using EDX, ICP, adsorptiye static method and XRD. Wet impregnation allows to obtain ZnO/SiO2 systems with the assumed ZnO content, regardless of the kind of zinc salt being supported (Table 4). Bulk and surface layer ZnO content is proportional to the amount of zinc salt being supported, and the surface layer is ZnO enriched (Table 3). XRD shows that ZnO supported on pyrogenic silica is amorphous. Increase in ZnO content decreases the ZnO/SiO2 system specific surface (more visible in Aerosil 300), whereas their capillary structure remains unchanged (Table 6). Deposition of ZnO on pyrogenic silica improves its dispersion and ZnO/SiO2 systems may be used as white fillers, crosslinking agents and activators of elastomer mixtures.
Keywords: „core-shell” dispersoids, pyrogenic silica, wet impregnation, ZnO/SiO2 systems, textural characteristics