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141.
Organic-inorganic composite materials have demonstrated many potential applications in environmental field. This paper presented a facile preparation method for γ-Fe2O3/PMMA/S-TiO2 nanocomposite with core-shell structure and its application in degradation of phenanthrene under visible light irradiation. Firstly, γ-Fe2O3/PMMA nanoparticles were synthesized by the modified-suspension-polymerization method. Then γ-Fe2O3/PMMA/S-TiO2 core-shell nanocomposites were prepared by adding as-synthesized γ-Fe2O3/PMMA nanoparticles into the sol solution formed by sol-gel method using tetrabutyltitanate as Ti source and thiourea as sulfur source. The characterization result of the obtained products by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy indicated that the layer of sulfur doped titania was successfully coated onto the surface of γ-Fe2O3/PMMA nanoparticles. Thermogravimetry (TG) analysis presented that the layer of sulfur doped TiO2 could efficiently reduce the decomposition of polymethylmethacrylate (PMMA) even at higher temperature up to 500 °C. UV–vis diffuse reflectance spectroscopy showed that γ-Fe2O3/PMMA/S-TiO2 nanocomposite clearly exhibits the red-shift of the absorption edge compared with γ-Fe2O3/PMMA/TiO2. The photocatalytic activity evaluation showed that the γ-Fe2O3/PMMA/S-TiO2 nanocomposite exhibited the best photocatalytic activity for degradation of phenanthrene under the conditions of 0.8 mol% of sulfur doping, calcination temperature at 300 °C and the addition concentration of 1.0 g/L. Moreover, the nanocomposites have good recovery ability by the recovery experiment. 相似文献
142.
The present paper reports the novel synthesis of polyaniline/magnesium boride (PAni/MgB2) nanocomposites. Nanowires 50–100 nm in diameter grown by the sol–gel technique were incorporated in the PAni to prepare PAni/MgB2 nanocomposites, which yielded an enhancement of conductivity by 5 orders of magnitude. PAni was synthesized through the chemical oxidative polymerization method. The composition of the prepared nanocomposites was tunable, i.e. the amount of dopant was varied and the effects on various parameters were observed by different techniques. The morphology of PAni/MgB2 nanocomposites was determined using SEM. The temperature dependence of the conductivity of all composites was measured in the temperature range 300–450 K and it was observed that samples having a high concentration of MgB2 show the highest conductivity. The molecular structure of the nanocomposites was further characterized by Fourier Transform IR spectroscopy which showed small structural changes in the backbone of PAni. I?V measurements showed that the current increases on increasing MgB2 content. UV?visible spectra exposed the occurrence of an indirect optical transition in the composite. © 2013 Society of Chemical Industry 相似文献
143.
Kate Ryan Sabine M. Neumayer Harsha Vardhan R. Maraka Nicolae-Viorel Buchete Andrei L. Kholkin James H. Rice 《Science and Technology of Advanced Materials》2013,14(1):172-179
AbstractNanocomposites of diphenylalanine (FF) and carbon based materials provide an opportunity to overcome drawbacks associated with using FF micro- and nanostructures in nanobiotechnology applications, in particular their poor structural stability in liquid solutions. In this study, FF/graphene oxide (GO) composites were found to self-assemble into layered micro- and nanostructures, which exhibited improved thermal and aqueous stability. Dependent on the FF/GO ratio, the solubility of these structures was reduced to 35.65% after 30 min as compared to 92.4% for pure FF samples. Such functional nanocomposites may extend the use of FF structures to e.g. biosensing, electrochemical, electromechanical or electronic applications. 相似文献
144.
《国际聚合物材料杂志》2012,61(7):544-557
Organo-modified fluorohectorite (OFH) clay-filled polysulfone (PSf) nanocomposites were prepared by a solution casting method. The dispersion of OFH clay in PSf nanocomposites was investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Thermal analysis revealed that incorporation of organoclay increased the thermal stability and glass transition temperature (Tg) of nanocomposites. The barrier properties of the nanocomposites studied were found to be significantly improved. It is worth mentioning that the improved thermal stability and barrier performance of these nanocomposites with the addition of organoclay in PSf matrix obviously offers immense potential in industrial and automobile applications. 相似文献
145.
This article describes the preparation and characterization of composites containing poly(ethylene-co-butyl acrylate) (EBA–13 and EBA–28 with 13 and 28 wt % butyl acrylate, respectively) and 2–12 wt % (0.5–3 vol %) of aluminum oxide nanoparticles (two types differing in specific surface area and hydroxyl-group concentration; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). A greater surface coverage was obtained with aminopropyltriethoxysilane than with octyltriethoxysilane. An overall good dispersion was obtained in the EBA-13 composites prepared by extrusion compounding. Composites with octyltriethoxysilane-coated nanoparticles showed the best dispersion. The addition of the nanoparticles to EBA–28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates. The nanoparticles had no effect on the crystallization kinetics in the EBA–13 composites, but in the EBA–28 composites the presence of the nanoparticles led to an increase in the crystallization peak temperature, suggesting that the nanoparticles had a nucleating effect in this particular polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
146.
Previous attempts to use polylactide (PLA) latex particles and nanofibrillated cellulose (NFC) in papermaking processing have been limited to low NFC content. In the present study, a bionanocomposite material was successfully produced using a PLA latex and NFC. The components were mixed using a wet mixing method and bionanocomposite films were made by filtration followed by hot pressing. In composite materials, the dispersion of the reinforcing component in the matrix is critical for the material properties. Biopolymers such as PLA are non-polar and soluble only in organic solvents; NFC is, however, highly hydrophilic. By utilizing latex, i.e., an aqueous dispersion of biopolymer micro-particles, wet mixing is possible and the problem of aggregation of the hydrophilic nanocellulose in organic solvent is avoided. The properties of the resulting NFC/PLA latex bionanocomposite films were analyzed. Thorough blending resulted in good dispersion of the reinforcing component within the matrix. Adding increasing amounts of NFC improved the Young's modulus, tensile strength, and strain at break of the bionanocomposite material. The increase in the tensile properties was linear with increasing NFC content as a result of the good dispersion. The NFC also improved the thermal stability of the bionanocomposite material. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
147.
The structure–transport properties of mixed soft‐segmented poly(urethane‐imide) (MSPUI) membranes and their microstructures were investigated. Polypropylene glycol, polycaprolactone diol and bis(3‐aminopropyl)‐terminated polydimethylsiloxane were used as the soft segments in the membrane synthesis via a three‐step polymerization reaction. The chemical structures of the MSPUI membranes were characterized using attenuated total reflectance Fourier transform infrared spectroscopy. Morphology and surface properties of the membranes were studied using scanning electron and atomic force microscopy techniques. Surface energy measurements indicated the enrichment of the hydrophobic soft segment in the membranes. The amorphous nature of the polymers was analysed using wide‐angle X‐ray diffraction. The effect of morphology on the permeability and selectivity of the membranes is discussed. Finally, membrane structure–transport property relationships were correlated. © 2013 Society of Chemical Industry 相似文献
148.
Gabriela Sacarescu Elena Taran Bogdan C Donose Mihaela Simionescu Valeria Harabagiu Liviu Sacarescu 《Polymer International》2012,61(12):1726-1732
To produce surface plasmons, silver nanoparticles are synthesized in situ in a pseudo‐template system based on polyhydrosilanes. Adsorption on the silver nanoparticle surface produces a thin layer of polymer with properties different from those of bulk polysilane. The metal‐adsorbed polymer layer serves as a spacer between the polysilane fluorophore and the plasmonic nanoparticle. This prevents quenching of the polysilane emission and leads to a strong surface‐enhanced fluorescence through coupling of surface plasmons having a resonance frequency that matches the emission frequency of the polymeric emitter. Copyright © 2012 Society of Chemical Industry 相似文献
149.
Arup Choudhury 《Polymer International》2012,61(5):696-702
Polyetherimide (PEI)/hydroxyl‐functionalized barium titanate (BaTiO3) nanocomposite films were successfully prepared through solution‐casting followed by subsequent thermal imidization. The results of Fourier transform infrared spectroscopy confirmed that the chemical treatment with hydrogen peroxide (H2O2) could efficiently derive hydroxyl groups on the surface of BaTiO3 nanoparticles. The strong interaction between the hydroxyl‐functionalized BaTiO3 and the PEI matrix greatly enhanced the particle dispersion as well as the interfacial adhesion, as evidenced by scanning electron microscopy. The PEI nanocomposite with hydroxyl‐functionalized BaTiO3 nanoparticles (50 vol% BaTiO3 loading) showed an increased dielectric permittivity of 52.78 at 1 kHz compared with the dielectric permittivity (33.87) of PEI/raw BaTiO3 composite. The loss tangent was still low (less than 0.03) when the content of hydroxyl‐functionalized BaTiO3 was 50 vol%. For PEI/BaTiO3 nanocomposites, the frequency and temperature dependences of the dielectric properties were significantly reduced through functionalizing the surface of BaTiO3 nanoparticles with H2O2. Different theoretical approaches were employed to predict the effective permittivity of the nanocomposite systems and the results are compared with the experimental results. Copyright © 2012 Society of Chemical Industry 相似文献
150.
Polymer/clay nanocomposites were prepared from dimethacrylate monomers, commonly used in dental restorative resins, and an organically modified silicate (montmorillonite). The photopolymerization process was hardly affected by the presence of the silicate filler, and thus 2 mm thick samples containing 3 wt% clay were extensively cured. Transmission electron microscopy revealed that the montmorillonite platelets were either intercalated or exfoliated. Nevertheless, for all formulations, intermediate‐sized aggregates of about 1 µm were present and their fraction increased as the amount of filler increased. The presence of the clay was found to have no major effect on the flexural modulus and compressive yield strength of the nanocomposites. Moreover, the water uptake of nanocomposites containing 3 wt% clay was about 10–15% higher than that of unfilled monomers. Modification of the clay surface with alternative organic cations is certainly necessary in order to achieve an optimal dispersion of the clay in the polymer matrix. Copyright © 2010 Society of Chemical Industry 相似文献