Zhuoru Yang

Hollow 0.3Li2MnO3·0.7LiNi(0.5)Mn(0.5)O2 microspheres as a high-performance cathode material for lithium-ion batteries.

Hollow 0.3Li(2)MnO(3)·0.7LiNi(0.5)Mn(0.5)O(2) microspheres are synthesized on a large scale through a simple in situ template-sacrificial route. Starting from porous MnO(2) microspheres, the hollow microspheres assembled with 0.3Li(2)MnO(3)·0.7LiNi(0.5)Mn(0.5)O(2) nanocrystals are formed by a nanoscale Kirkendall effect. The nanocrystal-assembled hollow 0.3Li(2)MnO(3)·0.7LiNi(0.5)Mn(0.5)O(2) microspheres exhibit a highly reversible capacity as high as 295 mAh g(-1) over 100 cycles and excellent rate capability (125 mAh g(-1) at 1000 mA g(-1)). Benefitting from a unique hollow and nanocrystalline architecture, the as-formed hollow microspheres show much enhanced high-temperature (55 °C) electrochemical performances, compared with the products obtained by conventional sol-gel/solid-state reaction methods. This work demonstrates that a fabrication strategy based on the present in situ template-sacrificial approach offers a new method for the design of high-performance cathode materials with hollow interiors for Li-ion battery applications.

Emission, mass balance, and distribution characteristics of PCDD/Fs and heavy metals during cocombustion of sewage sludge and coal in power plants.

The emission, mass balance, and distribution characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as those of heavy metals (Hg, Cd, Pb, Cr, and Cu) were investigated during the cocombustion of 5%, 10%, 15%, and 20% sewage sludge (SS) in a pulverized coal power plant. The PCDD/F emissions increased from 7.00 to 32.72 pg I-TEQ/Nm(3) as the amount of SS in the mixed fuel (MF) increased. High sulfur content and relatively low chlorine levels in MF resulted in lower PCDD/F emissions. SS exhibited a remarkable difference in congener profiles compared with flue gas, bottom ash, and fly ash. The negative dioxin mass balance indicated that the cofiring of SS with coal in power plants was not a source but a sink of dioxins. The concentrations and emission factors of heavy metals in flue gas and bottom ash, as well as fly ash, all exhibited a tendency to increase with increasing input values of heavy metals in MF. The distribution characteristics of the investigated heavy metals were primarily dependent on the evaporative properties of these metals. The availability of chlorine could alter the heavy metal distribution behavior. The emitted pollutants in the power plant were below the legal limits.

Dissipative particle dynamics study on the mesostructures of n-octadecane/water emulsion with alternating styrene–maleic acid copolymers as emulsifier

For the first time dissipative particle dynamics (DPD) simulations were employed to study the microstructures of an emulsion with alternating copolymers as the emulsifier. To model the alternating copolymers, an angular force was introduced by determining the stiffness parameters based on a linear quantitative structure–property relationship model. We studied the kinetics of emulsion formation by analyzing the time evolution of pressure, temperature, droplet number, the mean end-to-end distance and the morphologies of the emulsified oil droplets. The effect of emulsifier concentration on the mesostructures of the emulsified oil droplets was also discussed and the simulation results can interpret the experimental results on the microscopic level. Accordingly, the DPD method is a powerful tool for investigating emulsions with alternating copolymers and may be extended to drug delivery systems containing these copolymers.

A novolac epoxy resin modified polyurethane acylates polymer grafted network with enhanced thermal and mechanical properties

This paper describes the synthesis of novolac epoxy resin modified polyurethane acrylates (EPUAs) for generating a grafted polymer network, which is different from the conventional interpenetrating polymer networks (IPN). It starts with preparing epoxy acrylate resins (EA) by the ring-opening reaction of novolac epoxy resin (EP) and acrylic acid (AA). Epoxy acrylate copolymers (EPAcs) with hydroxyl groups were prepared by the copolymerization of EA and acrylic monomers. EPUAs were obtained by reacting EPAcs with curing agents (polyisocycanate HDI-trimer and phthalic anhydride). The chemical structures of the obtained EA and EPAcs were characterized by Fourier-transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectra (1H NMR). The influence of EP on chemical and physical properties of EPUAs, including fracture surface morphology, thermal stability, tensile strength, elongation at break, glass transition temperature (Tg), cross-linking density, shore hardness, water absorption, adhesion, etc., were investigated as well. It is demonstrated that the incorporation of EP into EPUAs greatly enhances the above physico-chemical properties of EPUAs.

Simultaneous prediction of chemical mass transfer coefficients and rates for removal of organic pollutants in ozone absorption in an agitated semi-batch reactor

Abstract The removal rate(s) of one or several organic pollutant(s) from water by ozonation and the chemical mass transfer coefficient of ozone in an agitated semi-batch reactor are predicted simultaneously using the explicit expression of enhancement factor in ozone absorption relating to the surface renewal theory presented elsewhere by this study group (Chinese J. Chem. Eng. 8 (2000) 236–240). By comparing with the iteration method proposed by Kuo (Environ. Prog. 1 (1982) 189–195) based on the film theory, no significant deviation has been found in simulating ozone absorption into the solution of 2,4-dichlorophenol (2,4-DCP). The predicted results also agree well with the measured data.

Cure kinetics and chemorheological behavior of a wind epoxy resin system and its viscoelastic properties reinforced by glass fiber matt with process of vacuum assisted resin transfer molding

In order to investigate the processability of a wind epoxy resin for the vacuum-assisted resin transfer molding (VARTM) process, a differential scanning calorimeter and rheometry instrument were applied to characterize the curing properties and study the chemorheological behavior to obtain a better understanding of the resin system in order to define the implementation of the process. The curing temperature parameters were established along with a cure kinetic model to predict the cure behavior. In addition, the influence of the gelation and vitrification was also examined by rheological methods. No obvious vitrification appeared in the epoxy system and the apparent active energy of the cure reaction calculated by gel time was almost the same as the differential scanning calorimetry result. What is more, the viscoelastic properties of the composite reinforced by glass fiber matt was characterized through dynamic mechanical analysis, and it proved that post-cure was necessary to ensure complete cure and that the stiffness increased several magnitudes after glass fiber reinforcement.

Mechano-Chemical Preparation and Application of Mulberry-Like CaCo3/SiO2 Composite Particles in Superhydrophobic Films

This study focuses on preparation of mulberry-like CaCO3/SiO2 composite particles with a mechanochemical method and their application in superhydrophobic films. Silicon dioxide nanoparticles were adhered to calcium carbonate microparticles to form mulberry-like composite particles through vigorous stirring, which prevented agglomeration of silicon dioxide nanoparticles and maintained their nanocharacteristics. Then, hexamethyldisilazane was employed for hydrophobic modification of the mulberry-like CaCO3/SiO2 composite particles. The effect of CaCO3/SiO2 mass ratios, stirring speed, reaction temperature, and amount of modifying reagent on morphology and lipophilicity of composite particles was studied. Moreover, the superhydrophobic films with excellent film properties were obtained by through combination of mulberry-like CaCO3/SiO2 hydrophobic composite particles and RTV silicon rubber. The water contact angle and sliding angle of the superhydrophobic surface were measured to be 170 ± 2.5° and 4°, respectively. This approach proves to be ideal for substantial improvement of the self-cleaning property of RTV silicon rubber anti-pollution flashover coating.

Preparation and Characterization of Soap-free Cationic Fluorinated Poly-styrene-acrylate Latex with Core-shell Structure

Soap-free cationic fluorinated Poly-styrene-acrylate latex particles with core-shell structure were synthesized by seeded semi-continues emulsion polymerization in the presence of water soluble cationic monomer Methacryloxyethyltrimethyl ammonium chloride (MADAC) and using ethanol as co-solvent. The effects of MADAC dosage and ethanol content on the stability of polymerization process and the properties of the latex particles were studied. The chemical component of the polymer was analyzed by Fourier transform infrared (FTIR). The surface element composition of the prepared copolymer film was analyzed by X-ray photoelectron spectroscopy (XPS), the micro-structure of the prepared latex particles were observed by transmission electron microscopy (TEM). The result shows that cationic soap-free fluorinated poly-styrene-acrylate emulsion with a core-shell structure can be prepared when monomer DAMAC is 6.0 wt% and ethanol is 7.5 wt%.

Preparation, characterization, and properties of novel bisphenol-A type novolac epoxy-polyurethane polymer with high thermal stability

In this study a series of modified bisphenol-A type novolac epoxy resins (MNEPs) were synthesized from bisphenol-A type novolac epoxy resin (NEP) and propionic acid (PA) by a one-step ring-opening reaction process in the presence of tetramethylammonium bromide as catalyst. Fourier transform infrared and 1 H-NMR were employed to confirm the chemical structures of the MNEPs. The spectra results indicated that MNEPs with different hydroxyl contents were obtained successfully by different ring-opening rates of NEP. In addition, Intercross-linked epoxy-polyurethane composites (MNEP-PUs) were also obtained by curing reaction among MNEP, cross linker polyisocyanate IL1351 and phthalic anhydride(PHA). The thermal stability of MNEP-PUs and the conventional polyol PU A450/IL1351 were determined and compared. The thermal analysis demonstrated that the obtained MNEP-PUs exhibited much better thermal stability than the conventional polyurethane system A450/IL1351, and the thermal stability of MNEP-PUs was correlated to the content of MNEP. Moreover, physico-chemical properties of MNEP-PUs such as pencil hardness, adhesive attraction, solvent resistance were reported. It demonstrated that incorporating MNEP into MNEP-PUs as inherent hardness of MNEP-PUs could greatly improve pencil hardness, adhesive attraction, water, acid and alkali resistance of MNEP-PUs.

Preparation and characterisation of aluminium pigments encapsulated by composite layer containing organic silane acrylate resin and SiO2

Purpose – The purpose of this paper is to enhance the anticorrosion property of aluminium pigments and to improve their compatibility with polymers in coating.Design/methodology/approach – Aluminium pigments encapsulated by organic‐inorganic layer were prepared by hydrolysis and condensation of organic silane acrylate resin and tetraethoxy silane (TEOS) on the surface of pigments via sol‐gel method. TEOS and poly (methyl methacryalte‐n‐butyl acrylate‐vinyl triethoxysilane) (PMBV) formed in advance by co‐polymerisation of methyl methacrylate (MMA), n‐butyl acrylate (BA) and vinyl triethoxysilane (VTES) were used as precursors. The adhesion property of the aluminium pigments was measured by peel test, and the loss of silvery appearance after encapsulation and acid soaking were both evaluated by colour lightness difference (ΔL) measurement. The encapsulated aluminium pigments were further characterised by means of FTIR, SEM, TG and XPS.Findings – It was found that PMBV‐SiO2 thin films could be formed on the ...