Advanced Materials Research Vols. 750-752

Abstract: Pd nanoparticles supported in functionalized mesoporous silica were prepared. Mesoporous silica support was modified with [3-(2-aminoethyl aminopropyl)] trimethoxysilane. The functionalized mesoporous silica can be loaded with palladium and the resulting material used as a catalyst for the Suzuki-Miyaura coupling reactions. Highly dispersed and uniform palladium nanoparticles could be detected using transmission electron microscopy. The Pd-SBA-15 nanocomposite exhibits an excellent catalytic activity and low Pd leaching for the Suzuki-Miyaura coupling reaction.

Abstract: In this paper, a series of novel halogen compounds, melamine halogen acid salts were directly synthesized by melamine and halogen acid in water phase. The chemical structures of melamine halogen acid salts were characterized by Fourier-transform infrared spectroscopy (FT-IR), elemental analysis and ¹H-NMR. Meanwhile, the thermal properties of compounds were investigated by thermogravimetric analysis (TGA). The TGA results showed that melamine halogen acid salts had good thermostability during polymer processing. Futhermore, limiting oxygen index (LOI) and vertical burning test were used to study the flame retardant properties of composites blended by melamine halogen acid salts and polymer. The results revealed good flame retardancy that flame retardant polyethylene with 2 wt% melamine hydrobromide in total 8 wt% flame retardants got LOI value of 29.7% and reached UL 94 V-0 rating.

Abstract: Ag-loaded Bi₂WO₆nanoparticles were prepared by hydrothermal method. The products were characterized by XRD, UV-vis DRS, SEM and BET. The results indicated that it was the orthorhombic phase of Bi₂WO₆ and showed a markedly blue-shift Compared with pure Bi₂WO₆. Ag/Bi₂WO₆photocatalysts exhibited obviously enhanced photocatalysis than pure Bi₂WO₆ in degrading phenol-containingwastewater under visible light irradiation. The influence of the content of silver on the photocatalyticactivity of Bi₂WO₆ has been investigated. The resultsrevealed that the significant enhancement of photocatalytic activity can beattributed to the synergetic effects between noble metal and semiconductor component.

Abstract: The mesoporous polyaniline (PANI)-TiO₂ composite microspheres were prepared by a facile hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area. The XRD pattern suggested that PANI did not modify the crystal structure of TiO₂ whereas PANI exhibited amorphous state. The SEM of PANI-TiO₂ displayed for microspheres. The gas sensitivity of the PANI-TiO₂ hybrid was also studied. The as-prepared sample was sensitivity to ammonia and ethanol and showed good reversibility. The PANI-TiO₂ hybrid material exhibits high sensitivity (0.96) to ammonia (150ppm) when operates at 373K.

Abstract: The Zn (II) complex [Zn (O₂CFcCO₂)(H₂O)₂]H₂O was synthesized with ferrocenedicarboxylic acid under mild conditions. Its crystal structure was characterized by elemental analysis, IR data and X-ray diffraction single crystal structure analyses. The Zn (II) coordination units are connected, forming one-dimensional chain. At the meanwhile, the luminescence properties and the electronic properties were determined.

Abstract: The gadolinium acrylate Gd (AA)₃/hydrogenated nitrile-butadiene rubber (HNBR) composites have been prepared by in-situ reaction with dicumyl peroxide (DCP) as vulcanizing agent. The original morphology of Gd (AA)₃ and its dispersion state in un-vulcanized and vulcanized rubber compound have been analyzed by scanning electron microscopy (SEM). The results demonstrated that Gd (AA)₃ dispersed uniform in the composite with smaller size and better interface bonding because of the in-situ reaction. The mechanical properties of Gd (AA)₃/HNBR reached the best when filled with 40 phr Gd (AA)₃ and the X-ray shielding property increased with the increasing filling amount of Gd (AA)₃.

Abstract: During graphene oxide separation process, the effects of the process parameters such as centrifugal separation time and ultrasonic treatment time on the particle size distribution of graphene oxide aqueous dispersion were studied. The results show graphene oxide has the narrower particle size distribution and the smaller nominal effective particle size with increasing the centrifugal separation time from 20 min to 160 min. And there is a critical time in the ultrasonic treatment to obtain the narrower particle size distribution and smaller nominal effective particle size of graphene oxide. Graphene oxide has the narrower particle size distribution and the smaller nominal effective particle size when the ultrasonic treatment time is 4 h.

Abstract: The SiO/C composite materials were prepared via a solution route and subsequent thermal treatment. The effects of carbon source on the particle morphology of composite, the graphitization degree of carbon component and the electrochemical performance of the prepared SiO/C composites were investigated by scanning electron microscopy (SEM), Raman spectrometer and electrochemical charge/discharge tests. The results reveal that the SiO/C composite synthesized with the epoxy resin as carbon source exhibits the higher graphitic degree and higher reversible specific capacity (~690 mAhg^-1) and excellent cycling stability.

Abstract: Mesocarbon microbeads (MCMBs) have been synthesized from coal tar pitch. Scanning electron microscopy (SEM) and laser particle size analyzer were used to evaluate the structure and partical size. The effect of process parameters on the growth and morphologies of MCMBs was investigated. The results show that the optimum temperature range is 410-430 °C and the growth time has a suitable range. The diameter and yield of MCMBs will increase and the spherical degree does not change with the extension of time.

Abstract: Copolymers of N-[(4-bromo-3,5-difluorine) phenyacrylamide (BDPA), with methyl methacrylate (MMA) were synthesized in N,N-Dimethylformamide at 75±1°C using 2,2-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The copolymers were characterized by FTIR and 1H NMR spectra. The glass transition temperature of the copolymers decreases with increase in BDPA content. The thermogravimetric analysis of the polymers showed that the thermal stability of the copolymer decreases with BDPA content.