Study on the properties of the Sb₂O₃ nanoparticles modified by different surfactants

In order to enhance the interface adhesion between polymer matrix and Sb₂O₃ nanoparticles, the surface of Sb₂O₃ nanoparticles was modified via the mechanochemical method and using different surfactants including stearic acid, coupling agent of organic titanate (NDZ-201) and silane coupling agent KH-560. The dispersibility, hydrophobicity, microstructures, particle size distributions, thermal stability and surface potential of the modified and unmodified Sb₂O₃ nanoparticles were characterized by transmission electron microscopy (TEM), surface contact angle measurement, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer, laser particle size analyzer and zeta potentiometer, respectively. The results show that the surface chemistry of the nanoparticles was grafted from hydroxyl groups to alkyl groups by reacting different surfactants with Sb₂O₃ nanoparticles and physical coating. Stearic acid can be effectively coated on the surface of Sb₂O₃ nanoparticles. Besides, the modified Sb₂O₃ nanoparticles have the better dispersibility than the unmodified Sb₂O₃ nanoparticles in octane due to the fact that the steric hindrance of modifier between nanoparticles prevents aggregation. The mean particle size of the modified Sb₂O₃ nanoparticles is smaller than that of the unmodified Sb₂O₃ nanoparticles. The mean particle size of Sb₂O₃ nanoparticles modified by 3 wt% KH-560 is 57 nm as a result of steric hindrance and lower surface potential. Furthermore, the water contact angle of Sb₂O₃ nanoparticles modified by 5 wt% stearic acid reached to 114°. (paper)