Advanced Materials Research Vols. 236-238

Abstract: α-MoO₃ microspheres assembled by nanorods were synthesized in room temperature ionic liquids (bmimBF₄: 1-butyl-3-methylimidazolium tetrafluoroborate) by microwaves heating method. The microstructure and morphology of the products were characterized by the techniques of X-ray powder diffraction (XRD), Fourier-transform spectrometer (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM). The influence factor such as the amount of ammonium heptamolybdenum tetrahydrate in ionic liquids was investigated in detail. The possible reaction mechanism was also discussed. It was demonstrated that the ionic liquid could act as template agent for the formation of α-MoO₃ microspheres. The present synthesis route is very simple and fast, and could be extended to the fabrication of other nanomaterials in ionic liquids.

Abstract: Nanocomposites were obtained by mixing elastomeric terpolymer and nano-SiO₂ in double-screw extruder at 130-150 °C, in which elastomeric terpolymer was prepared by terpolymerization of poly(methyl methacrylate (PMMA) macromonomer, butyl acrylate(BA), and acrylic acid(AA) in benzene using azobisisobutyronitrile (AIBN) as initiator. The results indicated that increasing the amount of PMMA, the molecular weight of PMMA and terpolymers as well as the content of carboxylic acid were favorable to increase the mechanical properties of nanocomposites. In addition, the tensile strength and the modulus at 300% elongation of nanocomposites reach to a maximum while the mass ratio of nano-SiO₂ to terpolymer is 3%.

Abstract: Nano-sized hollow spheres self-assembled by ZnO nanocrystals have been prepared by microemulsion method with dodecyl benzene sulfonic acid sodium salt (DBS) as the modifying and protecting agent. The product was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high High-resolution electron microscopy (HRTEM) energy dispersive spectroscopy (EDS) and photoluminescence (PL) spectra. The results showed that the hollow sphere was composed of ZnO nanocrystals. And the PL spectrum showed a different emission at 438 nm. After heated the product, PL emission peak changed. A possible formation mechanism was also proposed.

Abstract: We reported here a novel procedure for preparing 2.5% beta cypermethrin/polyacrylate nanocapsules using miniemulsion polymerization method, in which formulation the stearic acid (SD) as assistant stabilizer and fatty alcohol-polyoxyethylene ether (n=9) sodium sulfate (AES) as emulsifier. The nanocapsules were characterized by IR, UV, transmission electron microscopy (TEM), laser particle size analyzer and TGA. It proves that beta cypermethrin nanocapsules have uniform size and core-shell structure, and the mean size is 49.1 nm. The encapsulation efficiency of nanocapsules is 84.6% and the loading capacity of nanocapsules is 13.4%. The analysis of FTIR and UV show there are no toxic organic solvent and benzene adjuvant existing in the formulation, therefore, the nanocapsule is eco-friendly. TGA analysis indicates the nanocapsule possesses release-controlled performance and could extend the duration.

Abstract: Biodegradable aliphatic-aromatic copolyesters/POSS nanocomposites were synthesized via in situ melt copolycondensation of terephthalic acid (TPA), poly(L-lactic acid) oligomer (OLLA), 1,4-butanediol (BDO) and polyhedral oligomeric silsesquioxanes (POSS) reagents (POSS-NH₂ and POSS-PEG). The morphologies and dispersions of two POSS reagents in the nanocomposites and their effects on the mechanical and thermal properties were investigated. TEM and XRD characterizations confirmed that POSS-NH₂ formed crystalline microaggregates and took poor dispersions in the nanocomposite, while POSS-PEG had better dispersion in the matrix. Due to the good dispersion and interfacial adhesion of POSS-PEG with the copolyester PBTL matrix, the tensile strength and the Young’s modulus greatly increased for PBTL/POSS-PEG nanocomposite. Moreover, compared with POSS-NH₂ the existence of POSS-PEG imparted PBTL good flexibility and increased the mobility of the chains, so the glass-transition temperature and the heat of melting as well as the elongation at break were obviously influenced for PBTL/POSS-PEG nanocomposite.

Abstract: The formation of inorganic/organic Complex Material from giant polyoxomolybdate (POM) macro-anions in solutions mixed a positively charged surfactant tetradecyltrimethylammonium bromide (TTA⁺Br^-1) was described.surfactant tetradecyltrimethylammonium bromide (TTA⁺Br^-1) was described. The complex can further dissolve in aqueous solution with the excess TTABr and the larger hydrophilicaggregations formed. TEM and Dynamic Light Scattering (DLS) investigations were applied to analyze the aggregations in the simple-phase solution.

Abstract: A novel method——Fenton/UV treatment, was used to modificate carbon nanotubes (CNTs) in our research. Effects of different molar ratios of Fenton reagents on the surface of CNTs were studied in our work. The purity of CNTs was investigated by TGA. The functional groups on the surface of CNTs were investigated by FTIR spectra, and the phase analysis of CNTs was investigated by X-ray diffraction analysis (XRD). The result show that it can introduce a great deal of hydroxyl groups onto the surface of carbon nanotubes, and almost never introduce impurities, when the molar ratio of Fe²⁺ and H₂O₂ is 1:40.

Abstract: CdS nanoparticles were prepared and simultaneously loaded on the ion exchange resin microspheres via a simple in-situ gas-solid reaction. X-ray diffraction (XRD), scanning electron microscope (SEM), EDX analysis and UV-vis spectra were used to characterize the products. The results indicated that the CdS nanoparticles were loaded on the ion exchange resin microspheres, and the average size of particles was approximately 5.3 nm. The nanoparticle coverage was high so that a continuous nanoparticle shell formed on the ion exchange resin microspheres. In addition, the effect of Pb²⁺ ions (aq.) on the luminescence of the CdS nanoparticles immobilized on the ion exchange resin microspheres were investigated. It was found that the luminescence intensity of the CdS nanoparticles changed significantly when Pb²⁺ ions were adsorbed on the sample. The lowest concentration of Pb²⁺ ions that can make the intensity change is 1.0´10^-20 mol×dm^-3, which implies that the CdS nanoparticles immobilized on the ion exchange resin microspheres are very sensitive to Pb²⁺ ions (aq.).

Abstract: Amorphophallus bulbifer (A. bulbifer) is a promising species in Amorphophallus sp., with great potentiality of developing, low risk for cultivation and considerable commercial benefits, mainly locates in tropical and subtropical regions or near the equator. Konjac glucomannan (KGM) is the main component of Amorphophallus tuber which is a water-soluble dietary fiber. In this work, some physiochemical properties of KGM in three Amorphophallus species flour [one was A.bulbifer, the other two were current main species namely Amorphophallus rivieri (A. rivieri) and Amorphophallus albus (A. albus)] were studied and compared with each other. The KGM content in A. rivieri, A. albus and A. bulbifer flour were 85.03%, 76.28% and 88.07% (w/w), respectively. The apparent viscosity, viscosity average molecular weight, whiteness, gel-forming properties and chemical structure of KGM in the three flours were investigated by using viscometer, colorimeter, texture analyzer and Fourier transform infrared (FT-IR) spectroscopy. The results indicated that the viscosity and M_w of A. bulbifer was the largest, gel strength was almost same (p>0.05) and the molecular structure were of no differences of three KGM. It may be proposed that transplanting A. bulbifer from its native land in the tropical and subtropical regions to temperate zone in the southwest part of China would be feasible, and it would cause the revolution of Amorphophallus sp. and more considerable benefits.

Abstract: Five different macroreticular resins (S-8, HPD750, AB-8, HPD100 and D101) were evaluated for the adsorption properties of the proanthocyanidins extracted from Rhodiola rose. The results showed that AB-8 displayed the optimal adsorption and desorption properties. The adsorption of AB-8 for proanthocyanidins followed Langmuir equation and belonged monolayer adsorption. The optimal purification conditions were as follows: the sample concentration of proanthocyanidins was 4mg/mL, sample flow rate was 1.5BV/h, proanthocyanidins could be entirely eluted with 3 bed volumes of 50% ethanol. Based on the experiment, the purity of proanthocyanidins product is 64%.