Chuyang Zhang

Electrospinning cellulose acetate nanofibers and a study of their possible use in high-efficiency filtration:

Cellulose acetate was dissolved in trifluoroacetic acid and electrospun onto polypropylene non-woven material. An upstream layer of polypropylene non-woven material was added to form a three-layered polypropylene/cellulose acetate/polypropylene filter. The thickness of the electrospun cellulose acetate layer was varied by changing the electrospinning time. The fabricated filter was then characterized. Cellulose acetate nanofibers were also electrospun onto an aluminum foil collector with the aim of studying the changes in fiber properties when they are electrospun onto the polypropylene non-woven material. The results obtained in this research work indicated that the layer of nanofibers electrospun onto polypropylene non-woven material increased the filtration efficiency of polypropylene non-woven material from 50.23% to 91.29%, but the quality factor reduced by 29.1%. When the cellulose acetate deposition time was increased from 3 h to 6 h, the filtration efficiency further increased to 98.26% and the quality factor increased by 0.6%. A comparison between cellulose acetate nanofibers electrospun using an aluminum foil as the collector and those electrospun directly onto the polypropylene non-woven material indicated that cellulose acetate fibers electrospun onto polypropylene non-woven material had poorer fiber quality properties.

Effect of Atmospheric Plasma Treatment on Carbon Fiber/Epoxy Interfacial Adhesion

In this work the effect of atmospheric plasma treatment on carbon fiber has been studied. The carbon fibers were treated for 1, 3 and 5 min with a He/O2 dielectric barrier discharge atmospheric pressure plasma. The fiber surface morphology, surface chemical composition and interfacial shear strength between the carbon fiber and epoxy resin were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and the single fiber composite fragmentation test. Compared to untreated carbon fibers, the plasma treated fiber surfaces exhibited surface morphological and surface composition changes. The fiber surfaces were found to be roughened, the oxygen content on the fiber surfaces increased, and the interfacial shear strength (IFSS) improved after the atmospheric pressure plasma treatment. The fiber strength showed no significant changes after the plasma treatment.

Mn3O4 hollow microcubes and solid nanospheres derived from a metal formate framework for electrochemical capacitor applications

Mn3O4 hollow microcubes and solid nanospheres were selectively fabricated from a metal formate framework ([CH3NH3][Mn(HCOO)3]) by employing the ion exchange reaction in alkaline solution under different hydrothermal conditions. The relationships between Mn3O4 morphology and reaction molar ratio and reaction time were investigated. When used as the electrode materials for supercapacitors, Mn3O4 hollow microcubes and solid nanospheres had specific capacitances of 176 and 150 F g−1 respectively at a current density of 0.3 A g−1 in 1 M Na2SO4. The specific capacitance retentions of the Mn3O4 hollow microcubes and solid nanospheres were 95% and 86% respectively after 8000 charge–discharge cycles at a current density of 2 A g−1. Electrochemical results show that the Mn3O4 hollow microcubes and solid nanospheres exhibit acceptable specific capacitance and excellent cycling stability.

Metal organic framework-derived Co3O4 microcubes and their catalytic applications in CO oxidation

Metal–organic framework (MOFs)-derived metal oxides with diverse morphologies and microporous structures have shown potential applications in heterogeneous catalysis. In this study, two types of porous Co3O4 catalysts, Co3O4–MA and Co3O4–DMA (MA = methylamine and DMA = dimethylamine), were successfully synthesized via a one-step pyrolysis of Co-based metal-formate frameworks, [Amine][Co(HCOO)3] (Amine = methylamine, dimethylamine), in air. The obtained porous Co3O4 catalysts were systematically characterized by XRD, SEM, TEM, XPS, H2-TPR, and N2 adsorption–desorption analysis. The results show that the obtained porous Co3O4 catalysts are composed of nanoparticles and inherit the morphology from the precursor [Amine][Co(HCOO)3]. Co3O4–MA and Co3O4–DMA exhibit an excellent catalytic activity for CO oxidation, with both of them reaching a 100% CO conversion at 170 °C.

The effects of humidity on the surface modification of wool fabric through atmospheric pressure plasma jet

Current research was carried out on hydrophilic wool fibers at three different humidity conditions through atmospheric pressure plasma jet (APPJ). Samples were taken to evaluate surface microscopic morphology, surface roughness, directional friction effect (DFE), and surface chemical composition. The scanning electron microscope (SEM) and fiber friction coefficient test (FFT) results show that wetting pretreatment has significant effect on surface etching and DFE, but very limited effect on surface roughness. Allwörden reaction and X-ray photoelectron spectroscopy (XPS) results reveal that extra moisture changes C, O, N, S contents and their related characteristic functional groups, therefore increases etching degree on wool fiber surface scales. It was concluded that APPJ treatment is effective in processing wool fiber with high moisture contents.