Papers by Author: Xiang Yang Xu

Abstract: Mechano-chemical modification (MCM) of nanodiamond was conducted with a stirring mill. A new type of silane coupling agent, GW was chosen as its modifier. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) were employed to study the surface properties of nanodiamond before and after treatments. Results showed that the peaks related to GW and the ball (for example, Fe, Si and Cl) appeared obviously after its MCM on their XPS spectra and mostly disappeared after its further purification with acid X or Y. A new peak located at 1382.48cm-1 was very strong after further purification. It was proven by their FT-IR spectra.

Abstract: A stirring mill, an ultrasonic bath and a high-speed shearing emulsifier were adopted to modify the surface characteristics of nanodiamond (ND) respectively. The ζ-potential, size distribution and Fourier transform infrared spectroscopy (FT-IR) of ND were measured to evaluate its properties. Results show that the ζ-potential of ND modified with SHP (either by Mechano-chemical Modification or Ultrasonic measurement) drops sharply. Results also show that the rotating speed of the emulsifier exerts little influence on the size D5 but great influence on the size D95 of ND.

Abstract: Nanodiamond prepared by detonation synthesis using explosives as the precursor exhibits serious agglomeration characteristics in non-polar medium such as clean oil. Mechanochemical measures were introduced to modify nanodiamond (ND) surface, improve its dispersion behavior and actualize suspension stability. Hyperdispersants’s adsorption can be intensified with the participations of mechanical forces, and the main mechanism of hyperdispersant may lie in the steric stabilization of its adsorption layer founded on ND surface. After the eagglomeration and dispersion treatments, a suspension containing ND particles with the average diameter of around 55 nm can be prepared and it can be reserved for over 6 months without any sedimentation.