Surface modification mechanism of magnesium oxysulfate whiskers via wet chemical method

Magnesium oxysulfate whisker（MOSW） was produced using magnesite and sulfuric acid as raw materials by hydrothermal method and further modified by taking zinc stearate as modifier via wet chemical method.The infiuences of the amount of modifier, slurry concentration, modification duration, modification temperature and the stirring rate on the surface modification were investigated. The effects of surface modification in functional groups, morphology and electron binding energies of surface elements of MOSW were characterized by Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. The mechanism of modification was analyzed by studying the microstructure model of the surface of MOSW, which was modified by zinc stearate. The results show that the coordination is generated by the Mg element and O in carboxylic ion of modifier, and the chemical bond could be obtained by modification. Moreover, the surface of MOSW bonds the molecules of zinc stearate, and it becomes rough. Then, the hydrophobicity of MOSW is also improved significantly. In addition, the 1s electron binding energies of Mg and O on the surface of MOSW decrease by1.2 and 0.2 eV, respectively.

Magnesium hydroxide whisker modified via in situ copolymerization of n-butyl acrylate and maleic anhydride

Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact angle and activation index. The thermal stability,functional groups, structure, morphology, phase composition and surface element valence of MH whiskers were characterized by thermogravimetry-differential scanning calorimetry(TG-DSC), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Results reveal that the contact angle and activation index of modified MH whiskers are 105°and 76.5%, the thermal stability shows little change, and the decomposition temperature ranges between 38 and419 ℃. The copolymer of n-butyl acrylate and maleic anhydride absorbed on the surface of MH whiskers leads to the increased diameter and makes the surface of whiskers be rougher. Furthermore, the absorption of element C on the surface of MH whiskers increases, and the diffraction intensity of C 1 s spectra increases; thus, the compatibility of whiskers in the organic phase can be improved significantly. Lastly, the surface molecular model of MH whiskers modified via in situ copolymerization of n-butyl acrylate and maleic anhydride is established.

Pure phase MoN: preparation by chemical-diffused permeation and enhanced conductivity with rare earth Gd

MoN was prepared by rare earth Gd thermaldiffused permeation method via solid–gas interface reaction using（NH_4）_4[NiMo6O_24H_6]·7H_2O（abbreviated as NiMo6） as the precursor. Thermo-gravimetric differential thermal analysis（TG–DTA） was used to study the product＇s stability. The results of X-ray diffractometer（XRD）and X-ray photoelectron spectroscopy（XPS） indicate that a new hexagonal crystal MoN forms after the rare earth gas permeation and Gd3＋are diffused as substitution ions into the crystal lattice of MoN, and the surface valence of elemental content was measured by XPS. The conductivity results by direct current（DC） four-probe method show that MoN obtained from the Gd thermal permeation exhibits conductor character in the temperature range of 298–740 K and semiconductor behavior in 740–800 K.