Wenbing Ding

Hollow Ferrocenyl Coordination Polymer Microspheres with Micropores in Shells Prepared by Ostwald Ripening

Hollow microspheres with pores in their shells have received much attention owing to their hierarchically porous structures and advanced applications in electrochemical capacitive energy storage, hydrogen storage, drug delivery, sensing, and catalysis. For example, Lou et al. reported that hollow SnO2 nanospheres with nanoporous shells showed high reversible charge capacity and good cycling performance. Zhu et al. investigated the drug-delivery properties of hollow silica spheres with mesoporous shells and found that the hollow microspheres were able to store significantly more molecules with higher release rates than conventional mesoporous silica. Template synthesis is one of the most-used strategies to prepare hierarchically hollow microspheres, especially for pores inside the shells. Braun and co-workers have prepared hollow ZnS microspheres with mesoporous shells using dual templates assembled by lyotropic liquid crystals on the surfaces of silica or polystyrene colloidal templates. Liu et al. have produced organic–inorganic hybrid hollow nanospheres with microwindows on the shells templated by tricopolymer aggregates. The template method is general to prepare hollow microspheres with pores in the shells, but expensive and tedious post-treatment processes, such as solvent extraction, thermal pyrolysis, or chemical etching, and resultant fragile frameworks, limit or even impair its applicability. 3, 4] As a result, it remains an important challenge to develop a convenient and template-free method to prepare hollow microspheres with porous shells. Porous coordination polymers are highly ordered porous multifunctional materials prepared by linking metal ions or metal oxide clusters with multidentate organic ligands without any additional template. Construction of shells of hollow materials with porous coordination polymers is an especially promising approach to design hollow microspheres with porous shells through a template-free method and to endow materials with multifunctionality, such as electric, magnetic, and optical properties. Herein, we report the formation of hollow coordination polymer microspheres with microporous shells by a one-pot solvothermal reaction without any additional template; the shells are constructed of iron-based ferrocenyl coordination polymers. We confirm that the Ostwald ripening mechanism is responsible for the formation of hollow cavities with controllable size. Hollow iron-based ferrocenyl coordination polymer microspheres (Fe-Fc-HCPS) were synthesized by a solvothermal reaction of FeCl3·6H2O with 1,1’-ferrocenedicarboxylic acid (H2FcDC) in N,N-dimethyl formamide (DMF; Figure 1a). The precipitate was collected by centrifugation and washed several times with DMF and CHCl3. The reaction temperature, reaction time, and molar ratio of reactants play important roles in the formation of hollow spherical particles. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy (OPM) were

Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater.

Porous magnetic microspheres with large particle size (350-450 microm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe(3)O(4)). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater.

Synthesis of Fe3O4@poly(methylmethacrylate-co-divinylbenzene) magnetic porous microspheres and their application in the separation of phenol from aqueous solutions

A simple strategy to fabricate magnetic porous microspheres of Fe(3)O(4)@poly(methylmethacrylate-co-divinylbenzene) was demonstrated. The magnetic microspheres, consisting of polymer-coated iron oxide nanoparticles, were synthesized by the modified suspension polymerization of methacrylate and divinylbenzene in the presence of a magnetic fluid. The morphology and the properties of the magnetic porous microspheres were examined by scanning electron microscopy, transmission electron microscopy, superconducting quantum interference device, Fourier transform infrared spectroscopy, thermogravimetry, and X-ray powder diffraction. The pore size distribution and the specific surface area of the microspheres were measured by nitrogen sorption and mercury porosimetry technique. As predicted from the previous knowledge, the magnetic porous microspheres possessed a high specific surface area using n-hexane as a porogen. It was further found that the amounts of divinylbenzene and methacrylate, the ratio of porogens, and the dosage of ferrofluids affect the specific surface area of the microspheres. Furthermore, the microspheres were applied to remove phenol from aqueous solutions. The results showed that the microspheres had a high adsorption capacity for phenol and a high separation efficiency due to their porous structure, polar groups, and superparamagnetic characteristic.

Study on Poly(ferrocenylsilane) and Its Promotive Effect to Decomposition of Ammonium Perchlorate

S OLID propellant is one of the most significant ingredients used in rockets. The burning rate of propellant is a vital parameter for rocket design. A promising method to enhance the burning rate of propellants is to use burning-rate promoters (BRPs). BRPs have become increasingly important and are receiving more attention recently due to their successful use in solid propellant burning-rate enhancement. Generally, there are several kinds ofBRPs; transitionmetal oxides, nanometal particles, metal chelate, ferrocene, and its derivatives. Transition metal oxide BRPs are cheap, but the burning-rate improvement of propellant is limited. The addition of nanometal particles can enhance the burning rate because nanometal particles have large specific surface areas and higher surface energy. However, nanometal particles are difficult to disperse well and passivation is needed for their surface to prevent spontaneous combustion in air [1]. Organic metal chelate BRPs, such as copper organic chelate and Plumbum iron double metal chelate, can greatly enhance the burning rate due to their good dispersion in propellants. Ferrocene and its derivatives have attracted much attention for their fascinating properties as BRPs [2]. They have been widely used in composite propellant, especially to enhance the burning rate of butyl hydroxide propellant, which contains ammonium perchlorate (AP) and aluminum powder. When ferrocene and its derivatives are used as BRPs, they are easy to migrate during storage. This migration affects their application in propellants. In this Note, we explore the possibility of using a series of poly(ferrocenylsilanes) with highmolecular weights as BRPs.

Recent Research Progress on Polymer Grafted Carbon Black and Its Novel Applications

Abstract Polymer grafting of carbon black (CB) has been intensely researched as polymer modification is one of the effective means for improving the solubility and compatibility of carbon black. Recent advances in the polymer grafting methods allow the introduction of polymers with well controlled composition, structure and molecular weight onto the surface of CB. In addition, modification by functional polymers provides a powerful impetus to extend the applications of polymer-CB composites such as sensitive materials. This review focuses on the development of these grafting polymerization methods and some novel applications of polymer grafted CB.

Synthesis of poly(acrylic acid) grafted carbon black and its application for sensing ethanol

Surface initiated reversible addition-fragmentation chain transfer (RAFT) polymerization techniques have been used to produce poly (acrylic acid) (PAA)-grafted carbon black (CB) nanoparticles. The surface of CB nanoparticles was functionalized in the presence of CB-supported macroRAFT agents. The resultant CB-g-PAA composites were characterized by Fourier transformed infrared spectra, thermal gravimetric analysis and energy dispersive spectrometry. The composites were dip-coated on epoxy resin electrodes to prepare novel thin film gas sensors, and the electrical responses of sensors towards ethanol were investigated. It was found that the sensors exhibited positive correlation electrical response towards ethanol vapor.