Xiaorui Zhang

In situ anchor of magnetic Fe3O4 nanoparticles onto natural maifanite as efficient heterogeneous Fenton-like catalyst

In situ anchor of magnetic Fe3O4 nanoparticles (NPs) onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe3O4/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe3O4 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe3O4 NPs was proposed. Then, the asobtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange (MO). The comparative tests on MO discoloration in different systems revealed that Fe3O4/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe3O4 NPs and the heterogeneous Fentonlike reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe3O4/maifanite composites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.

The preparation of a three-layer “core–shell” structured epoxy-acrylate emulsion

“Core–shell” structured epoxy-acrylate emulsions with different contents of epoxy resins were synthesized. Styrene (St), butyl acrylic (BA), methyl methacrylate (MMA) and epoxy resin (E-51) were used as the main raw materials. The fine control of the epoxy content was the key approach to design the morphologies of the emulsion. Due to the different epoxy contents, there was a transition of the particle morphologies from irregular structure, to two-layer core–shell structure to three-layer core–shell structure. The particle size became larger and then smaller again, and the thermal stability of the emulsion decreased with the increase of the epoxy content. The emulsion with clear three-layer “core–shell” structures and uniform particle size distribution could be prepared when the content of epoxy resin was 30 wt%. The corresponding film prepared by the emulsion had the characteristic of self-stratification.

Improvement of graphene oxide/epoxy resin adhesive properties through interface modification

The heat-conducting, dielectric, and bonding properties of a composite adhesive have been enhanced using toluene diisocyanate (TDI) to chemically modify the interface between graphene oxide (GO) and epoxy resin (EP), which was characterized using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The thermal conductivity of TDI10-GO0.5/EP was 0.624 W·m−1·K−1 (166% of EP and 117% of GO0.5/EP), with its TDI10-GO0.5/EP interfacial thermal resistance being reduced by a factor of 36 times GO0.5/EP. The insulating properties of the adhesive in small resistors and capacitors were improved by the inclusion of GO, with the dielectric strength of the adhesive shown to be 25.96 kV·mm−1 and its volume resistivity found to be 1.50 × 1014 Ω·m.