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23 results on '"Han, Tongwei"'

12. Synthesis and Application of New Polyphosphazene Microsphere Photocatalysts

Author

Xiaoyan Zhang, Wo Xinxing, Han Tongwei, Ren Shiman, Deng Yiran, Shufu He, and Hongmei Wang

Subjects
Materials science, Polymers and Plastics, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, Zinc, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Microsphere, Catalysis, Chemical engineering, X-ray photoelectron spectroscopy, chemistry, Materials Chemistry, Photocatalysis, Polyphosphazene, Fourier transform infrared spectroscopy, 0210 nano-technology
Abstract

Polyphosphazene (PZS) microspheres attached with zinc oxide (ZnO) nanoparticles were successfully synthesized by a simple method. The morphology and structure were characterized by FTIR, SEM and TEM. The characterization results show that the ZnO nanoparticles are attached on the surface of PZS microspheres. The resultant microspheres are about 1.3 μm in diameter and the attached individual ZnO nanoparticles are about 20 nm. The XRD, EDX and XPS analysis demonstrate that the nanoparticles in the resultant microspheres are ZnO nanoparticles. The thermostable properties were investigated by TGA. The data of the photochemical catalysis shows that the product has very good application in photochemical catalysis. The photocatalytic activities of the PZS/ZnO are much higher than that of the pure PZS and ZnO, due to the combination of their merits and the synergistic effects on the enhancement of their photochemical catalytic performance. This is a novel, simple and economic method to preparing hybrid inorganic–organic microspheres using for photochemical catalysis.

Published
2019

14. New organic–inorganic hybrid polymers as Pickering emulsion stabilizers

Author

Mingqing Hua, Han Tongwei, Xiaoyan Zhang, Ren Shiman, and Shufu He

Subjects
chemistry.chemical_classification, Materials science, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, Pickering emulsion, 0104 chemical sciences, Microsphere, Colloid and Surface Chemistry, chemistry, Chemical engineering, Organic inorganic, Surface modification, Particle, Polyphosphazene, 0210 nano-technology
Abstract

Novel polyphosphazene (PZS) microspheres with a unique organic–inorganic hybrid cyclomatrix structure are used as stabilizers for the preparation of Pickering emulsions droplets. Both water-in-oil (W/O) and oil-in-water (O/W) polyphosphazene Pickering emulsions can be fabricated. Size control of the droplets was conducted by varying the concentration of PZS microspheres. The mean diameter of the W/O emulsion droplets varied from 150 to 400 μm at PZS microspheres loadings of between 3.3 and 20 mg/mL at φwater = 0.091. In contrast, the mean diameter of the O/W emulsion droplets varied from 60 to 100 μm at PZS microspheres loadings of between 0.25 and 1.5 mg/mL at φoil = 0.091. The types of the emulsions were determined by using oil-soluble and water-soluble fluorescent dyes to label the oil and water phases, respectively. The influence of particle surface modifications on Pickering emulsion formation was investigated by attaching fluorescent organic dyes or inorganic Fe3O4 nanoparticles to the PZS microspheres. PZS microspheres with surface-attached organic dyes formed large and unstable W/O droplets whilst surface modification with inorganic magnetic Fe3O4 nanoparticles produced stable O/W droplets. Furthermore, colloidosomes were prepared by cross-linking W/O PZS Pickering emulsions.

Published
2018

23. Effects of temperature and strain rate on the mechanical properties of hexagonal boron nitride nanosheets.

Author

Han, Tongwei, Luo, Ying, and Wang, Chengyuan

Subjects
*BORON nitride, *TEMPERATURE, *STRAIN rate, *MOLECULAR dynamics, *STRESS-strain curves, *YOUNG'S modulus
Abstract

The effect of temperature and strain rate on mechanical properties remains an open topic in research of hexagonal boron nitride (h-BN) nanosheets. To examine these fundamental issues we have performed molecular dynamics simulations to record the stress–strain curves in tensile tests and measure Young's modulus, fracture strength and fracture strain in armchair and zigzag directions. Comparing the results obtained at different temperatures and strain rates we have quantified the effects of the two factors on the tensile properties of the h-BN nanosheets. The influence of crystal orientation is also examined in the present study. It is found that the h-BN nanosheets are basically an anisotropic material whose tensile properties vary substantially with temperature and strain rate. In particular, a yielding platform is observed for the h-BN nanomaterial at relatively low temperature. [ABSTRACT FROM AUTHOR]

Published
2014
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