ABSTRACT
282The nickel stearate hydrosols were prepared by mixing aqueous sodium stearate and nickel chloride solutions in the present study. Nickel stearate powder with 50 nm crystal size and 11 pm particle size was obtained by drying of the precipitate separated by filtration of the nickel stearate hydro- sols. The powder was characterized by FTIR spectroscopy, X-ray diffraction, differential scanning calorimetry, thermal gravimetry, hot-stage microscopy, and colorimetry. The nickel stearate had a solid-solid phase transition at 65°C and become liquid at 100°C. Hot-stage microscopy indicated the melting occurred in a wide temperature range. Spherical liquid droplets were observed in molten nickel stearate. TG analysis indicated NiO and Ni formed as a solid residue and distearyl ketone as the volatile fraction on heating nickel stearate up to 800°C and keeping the temperature constant at 800°C for 20 min. The hydrophilic cellulose surface of a filter paper was changed to hydrophobic surface by wetting it with nickel stearate hydrosol and then drying. The water contact angle at initial time was increased from 30° to 120° and 115° in one surface-coated and dip-coated filter papers, respectively.
