Surface Modification of Magnesium Sulfate Whisker with Stearic Acid

Abstract

In order to enhance the interfacial adhesion between magnesium oxysulfate whisker (MOSw) particles and polymers, the hydrophobicity of MOSw was improved by surface modification using stearic acid. The morphologies and structure of MOSw before and after surface modified (MOSw-SA) were characterized by field emission scanning electron microscope (FESEM) and X-ray powder diffraction (XRD). The interfacial interactions between MOSw and stearic acid were studied by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that the surface of MOSw was changed from being hydrophilic into being hydrophobic. And the stearic acid molecular binds strongly to the surface of MOSw. Chemical bond (COO-Mg<) was formed by the reaction between R–COOH and the hydroxyl group of MOSw. The reaction occurred only between the stearic acid and the surface of MOSw without altering MOSw’s morphology and crystal structure. Besides, the reaction mechanism of surface modification which was similar to the “acid-base neutrilization†was proposed.