Characterization of physicochemical properties of the inorganic components in the "core-shell"-structured polymer mixtures. Part I. The precipitated silica systems

Novel type dispersoids of the core-shell" structure, viz., ZnO/SiO2 systems containing 1, 4, 8, 12 or 20 wt. % ZnO, were prepared by wet-impregnating the (Zeosil 175 MP and Ultrasil VN2) precipitated silicas with aqueous solutions of Zn(NO3)(2), Zn(CH3COO)(2) and Zn(NH3)(4)(NO3)(2). The systems were examined by EDX, ICP, adsorptive static method, XRD and FTIR to determine physicochemical properties. The wet-impregnation technique enabled the ZnO/SiO2 systems to be prepared with the intended ZnO percentages incorporated regardless of the nature of the zinc salt used (Table 5). EDX showed the surface layer to contain more ZnO than assumed (Table 3). As the ZnO percentage rose, the specific surface of the ZnO/SiO2 system decreased, whereas its capillary structure remained unaffected (Table 7). XRD showed the ZnO deposited on precipitated silica to be amorphous and to be more dispersed which makes the ZnO/SiO2 systems suitable as activators, crosslinkers, and white fillers.