Zeng Hanmin

The reduction property of activated carbon fibers

Abstract The redox characteristics of different ACFs were studied by use of X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and other analytic methods. The experimental results indicated that reducing properties are characteristic for ACF. All ACFs have reduction ability and can reduce ions of higher standard potentials to elemental metals or lower-valence compounds or ions. The reduction capacity of ACF is closely related to the standard potential of the oxidant used. The factors that are advantageous to the increase of standard potential of oxidants or decrease of potential of the ACF will be advantageous to the increase of reduction capacity. In bicomponent systems, ACF reacts primarily with the oxidant of higher potential.

Studies on the mechanism of the reaction of activated carbon fibers with oxidants

Abstract In this paper, the mechanism of the reaction of activated carbon fibers (ACFs) with oxidants was studied by means of elemental analysis, surface groups analysis, X-ray photoelectron spectroscopy, gas chromatography, pH determination, and other techniques. The experimental results indicated that the reduction ability of ACF is mainly associated with the edges rather than the surface of the microcrystal carbon. The oxygen-containing functions can contribute only a small part of the reduction capacities of ACF. When ACF is oxidized by oxidants, the oxygen content and the amounts of hydroxyl, carbonyl, and carboxyl groups of ACF increase. The oxidation of ACF involves at least two processes, which are the formations of hydroxyl (or phenolic) groups and of carbonyl (or carboxyl) groups. Furthermore, the oxidation of ACF produces carbon dioxide and H + ion. The reduction capacity was larger than the amount of carbon dioxide released but approximately equal to the H + produced.

Preparation of the amidoxime group containing chelating fiber and adsorption property of gold. I : Preparation of chelating fiber by amidoximation of polyacrylonitrile fiber

The amidoximation process of polyacrylonitrile fiber was studied. The results showed that it is possible to prepare a chelating fiber with high adsorption capability for Au3+ and reasonable mechanical properties by the amidoximation of PAN fiber. With an increase of reaction time or concentration of agent, the conversion of nitrile groups in PAN increases rapidly at first, and then more slowly. When the reaction temperature is higher than that at which the paracrystalline region of the fiber is destroyed, the conversion of nitrile groups greatly increases, however, the mechanical properties of the fiber are inferior.

Preparation of amidoxime group-containing chelating fibers and their gold absorption properties. II. A preliminary investigation of the absorption behavior of Au3+ onto chelating fibers containing amidoxime groups

The absorption behavior of ionic gold onto chelating fibers containing amidoxime groups has been investigated. Chelating fibers not only present high absorption capacity, high absorption velocity and high selectivity to Au3+ ion, but also are able to reduce the absorbed Au3+ to metallic gold. When the fiber containing gold is burnt, spongy metallic gold is obtained. In the absorption process, the amidoxime group in the chelating fiber is gradually destroyed and a carboxyl group is formed.

Self-organization of CdS nanoparticles in polystyrene film

Self-organization of nano-CdS particles in polystyrene can be observed by encapsulating the particles with n-dodecyl mercaptan owing to a strong electron transfer interaction between the modified CdS nanoparticles and aliphatic carbons in polystyrene. Consequently, ultraviolet/visible absorption edge of the treated nano-CdS/polystyrene composites is further blueshifted in addition to the shift caused by the quantum size effect, and the fluorescence emission peak of the composite becomes redshifted and narrow.

Transcrystalline structure of PEEK

Abstract The structure of the interfacial transcrystallinity of poly(ether ether ketone) (PEEK) around carbon fibre has been studied. Crystal growth unhindered in the direction normal to the fibre axis, due to the very high nucleation density of PEEK on the fibre surface, is the reason that transcrystallinity can develop. In PEEK transcrystallinity, the lamellae are oriented perpendicular to the fibre axis, leading to the particular optical properties of transcrystallinity.

Molecular Entanglement Analysis Based on the Damping Behavior of Polycarbonate/Epoxy Resin Semi-Interpenetrating Polymer Network

The characteristics of entanglement structure in polycarbonate/epoxy semi-interpenetrating polymer network at molecular level have been investigated by dynamic mechanical spectrum. It is found that the relaxation of entanglement chains is a kind of synergetic relaxation, which will induce additive internal friction and decrease the apparent activation energy and Tg. The loss areas can represent the degree of interpenetration between the different segments at molecular level.