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1.
Metal/oxide nanoparticles are attractive because of their special structure and better properties. The Ni/TiO 2 nanoparticles were prepared by a liquid phase chemical reduction method in this paper. The obtained‐products were characterized by inductively coupled plasma (ICP), X‐ray diffraction (XRD), high‐resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The results show that Ni particles in Ni/TiO 2 nanoparticles exhibit better dispersion and the size of most Ni particles is 10 nm or so. The catalytic activity of Ni/TiO 2 nanoparticles on the thermal decomposition of ammonium perchlorate (AP) was investigated by simultaneous thermogravimetry and differential thermal analysis (TG‐DTA). Results show that composite process of Ni and TiO 2 can improve the catalytic activity of Ni nanoparticles on the thermal decomposition of AP, which is mainly attributed to the improvement of Ni dispersion in Ni/TiO 2 nanoparticles. The catalytic activity of Ni/TiO 2 nanoparticles increases with increasing the weight ratio of Ni to AP. 相似文献
2.
AbstractVegetable oil based environmentally friendly polyurethane-TiO 2 nanocomposite coatings have been synthesized by using sunflower oil derived diol, toluene diisocyanate and TiO 2 nanoparticles. The chemical structure was confirmed by FTIR and NMR techniques while physico-chemical testing was carried out by standard laboratory methods. Physico-mechanical and anticorrosive tests of the coatings (in different corrosive media) have been investigated by standard methods. In addition to this the morphology and thermal stability behavior of the coatings have been carefully investigated by different techniques like XRD, TEM, TGA/DTG and DSC. The comparison of the performance of nanocomposites with the respective virgin polyurethane coatings reveals that the dispersion of nanoTiO 2 enhanced the mechanical, corrosion and thermal stability behavior of the polymer. The synthesized nanocomposites can be used safely upto 250–275?°C. These sunflower oil derived polyurethane nanocomposites can be used in the world of protective coatings, as an alternative of petroleum derived corrosion protective coating materials. 相似文献
3.
Transparent organic-inorganic nanocomposites were successfully synthesized from sulfonic acid-modified poly(bisphenol A carbonate) (SPC) and TiO 2 or ZrO 2 nanoparticles. The dispersibility of nanoparticles was significantly improved by both the surface treatment of nanoparticles with phosphoric acid 2-ethylhexyl esters (PAEH) and the introduction of a sulfonic acid moiety into the PC chain. It was found that in some cases, crystallization of the matrix caused a reduction in transparency. Efficient dispersion of nanoparticles and the absence of crystallization resulted in highly transparent nanocomposites with up to 42 wt% TiO 2 and 50 wt% ZrO 2 nanoparticles. The refractive indices of the nanocomposites based on SPC increased with the increasing amount of nanoparticles. Theoretical equation based on Maxwell-Garnett effective medium theory provided reasonably close estimation of the refractive indices to the experimentally observed values. The prepared nanocomposites had lower thermal stability than the host matrix polymers. 相似文献
4.
利用偶联剂 γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)对纳米TiO 2进行表面预处理, 在此基础上通过分散聚合工艺制备聚苯乙烯(PSt)接枝包覆纳米TiO 2. 运用红外光谱、热重分析及透射电镜对处理前后纳米TiO 2进行了表征, 并通过紫外人工加速老化试验比较了表面处理前后纳米TiO 2对聚丙烯/聚苯乙烯(PP/PSt)体系的抗紫外老化性能. 结果显示: KH570与纳米TiO 2表面羟基进行了缩合, PSt在粒子表面实现了接枝聚合, 接枝率约为60% ( w); PSt接枝包覆纳米TiO 2呈均匀的微球形, 纳米TiO 2被包覆于微球内部; PSt接枝包覆后纳米TiO 2在PP/PSt中的分散效果较改性前有显著的改进, 其抗紫外老化性能明显优于改性前体系. 相似文献
5.
Polyethylene terephthalate (PET)/Polypropylene (PP)/TiO 2 nanocomposites were prepared by compounding a PP/TiO 2 nanocomposite premix with PET in absence and presence (up to 6 vol %) of maleic anhydride grafted polypropylene (PP‐ g‐MA). In absence of PP‐ g‐MA, the TiO 2 nanoparticles were mainly located at the PET/PP interface and to a lesser extent in the dispersed PET droplets. As the TiO 2 nanoparticles were coated by polyalcohol their surface could react with PP‐ g‐MA and thus improving the compatibilization with PP. Therefore in presence of PP‐ g‐MA the TiO 2 nanoparticles were preferentially located in the PP. The incorporated TiO 2 nanoparticles exerted a compatibilization effect on the PET/PP blend. Depending on the location of TiO 2 three different compatibilization mechanisms were proposed to be at work: (1) Locating at the interface, the TiO 2 nanoparticles decrease the free energy of mixing, and thus increase the thermodynamic stability of the nanocomposites; (2) The TiO 2 nanoparticles at the interface also prevent the coalescence of PET droplets; (3) Preferentially located in the PP matrix, the TiO 2 nanoparticles decreased the viscosity ratio which facilitated the droplet breakup of PET. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1616–1624, 2009 相似文献
6.
Novel epoxy nanocomposites based on a diglycidyl ether of bisphenol A (DGEBA) epoxy, an epoxy functionalized hyperbranched polymer (HTTE) and nano‐Al 2O 3 were synthesized with the aim of determining the effect of the nano‐Al 2O 3 particles and HTTE on the structure and properties of epoxy nanocomposites. The mechanical properties, thermal conductivity, bulk resistivity, and thermal stability of the nano‐Al 2O 3/HTTE/DGEBA ternary composites were evaluated and compared with the corresponding matrix. The improvement in impact properties of these nanocomposites was explained in terms of fracture surface analysis by SEM. The results indicate that the incorporation of nanoparticles and hyperbranched epoxy effectively improved the toughness of epoxy composites without sacrificing thermal conductivity and bulk resistivity compared to the neat epoxy and Al 2O 3/DGEBA, obtaining a well dispersion of nanoparticles in epoxy matrix and solving the drawbacks for single fillers filled epoxy nanocomposite. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
7.
In this present study, biodegradable PBAT nanocomposites containing different weight percentages (1, 3, 5, 7, and 10% w/w) of TiO 2 nanoparticles were prepared by using solvent casting technique, chloroform as a solvent. The microstructure and morphology of the as‐synthesized poly(butylene adipate‐co‐terephthalate) (PBAT)/TiO 2 nanocomposite films were characterized by Fourier‐transform infrared, X‐ray diffraction, scanning electron microscopy, and transmission electron microscope. The thermal degradation of PBAT composites was studied by using thermogravimetric analysis. The mechanical strength of the films was improved by increasing TiO 2 concentration. Tensile strength increased from 32.60 to 63.26 MPa, respectively. Barrier properties of the PBAT/TiO 2 nanocomposites were investigated by using an oxygen permeability tester. The oxygen permeability (oxygen transmission rate) decreased with increasing the TiO 2 nanoparticle concentrations. The PBAT/TiO 2 nanocomposite films showed profound antimicrobial activity against both Gram‐positive and Gram‐negative foodborne pathogenic bacteria, namely, Escherichia coli and Staphylococcus aureus, to understand to the zone of inhibition. These results indicated that filler–polymer interaction is important and the role of the TiO 2 as a reinforcement in the nanocomposites was evident. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
8.
A new method of surface modification of TiO 2 nanoparticles by surface-grafting l-lactic acid oligomer was developed. The surface-grafting reaction was evaluated by Fourier transformation infrared (FTIR) and thermal gravimetric analysis (TGA). The results showed that l-lactic acid oligomer could be easily grafted onto the TiO 2 nanoparticles surface in the presence of stannous octanoate and the highest amount of grafted polymer was about 8.5% in weight. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results showed that grafted TiO 2 (g-TiO 2) in chloroform or PLLA matrix approximated to uniform, while unmodified TiO 2 nanoparticles tended to aggregate. The tensile strength of this material was greatly improved by the addition of g-TiO 2 nanoparticles in poly(l-lactide) (PLLA) matrix. The tensile strength of the g-TiO 2/PLLA nanocomposite containing 5 wt.% of g-TiO 2 was 72 MPa, which was 23.1% higher than that of pure PLLA. Even though the incorporation of the TiO 2 nanoparticles into PLLA led to the deterioration of its elongation at break, the g-TiO 2/PLLA nanocomposite also exhibited better ductility than that of TiO 2/PLLA nanocomposite. 相似文献
9.
The TiO 2 nanoparticles are electrospun with polyacrylonitrile (PAN) polymer solution onto the discharged battery coal (DBC) electrode and the results are evaluated as a supercapacitor. The morphology and chemical composition of the synthesized TiO 2 nanoparticles and PAN+TiO 2 nanocomposite fibers were characterized by Scanning electron microscopy, thermogravimetry and FTIR analysis. Supercapacitor measurements and electrochemical characterizations of the electrodes examined by cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical measurements showed that the best current value was obtained from PAN and TiO 2 coated DBC. The performances of both PAN and PAN+TiO 2 coated DBC electrodes were investigated as supercapacitors. PAN+TiO 2/DBC showed the best specific capacitance value of 156.00 F g −1 and PAN/DBC showed 74.93 F g −1. In addition, PAN+TiO 2/DBC exhibited reliable stability performance over 2000.00 cycles. 相似文献
10.
This study focused on the fabrication of poly(n-butyl methacrylate) (PBMA) nanocomposites with various concentrations of cerium-doped titanium dioxide (Ce–TiO2) nanoparticles via in situ polymerization technique. The structural characterization and the material properties of all the composites were analyzed by UV–visible, FTIR, XRD, SEM, DSC, TG, and tensile strength measurements. The UV–visible and FTIR studies confirmed the effective inclusion of Ce–TiO2 nanoparticles into the PBMA matrix. The change in amorphous morphology of PBMA to a crystalline structure was observed from the XRD pattern. The SEM morphology revealed the attachment of nanoparticles in the polymer matrix. The inclusion of Ce–TiO2 nanoparticles enhanced the glass transition temperature, and thermal stability of the PBMA matrix was revealed from DSC and TG, respectively. The tensile strength of PBMA was greatly enhanced by the addition of Ce–TiO2 nanoparticles. The AC conductivity, dielectric constant, and dielectric loss studies were also performed in the frequency range 102–106 Hz, and it was observed that addition of Ce–TiO2 nanoparticles greatly enhanced the electrical properties of PBMA. The change in dielectric constant with the addition of nanoparticles was correlated with a theoretical modeling study. This work also extended to study the role of Ce–TiO2 nanoparticles in the reinforcing mechanism of the nanocomposite by comparing the actual tensile strength of the composite with different theoretical modeling. The high dielectric constant and tensile strength of composite are beneficial in designing lightweight and highly efficient nanoelectronic materials based on the family of polybutyl acrylates. 相似文献
11.
We developed a novel method for preparing poly(ethylene terephthalate)/BaSO 4 nanocomposites, which were synthesized by in situ polymerization of terephthalic acid (TPA), ethylene glycol (EG) and BaSO 4 nanoparticles prepared by reacting H 2SO 4 with Ba(OH) 2 in ethylene glycol (EG). It was shown that the addition of BaSO 4 would not influence the synthesis of PET. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM), and the nanoscale dispersion of BaSO 4 particles in the PET matrix was observed when the BaSO 4 content is below 4 wt%. Moreover, the thermal properties of the nanocomposites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results suggest that the degree of dispersion of BaSO 4 particles in the PET matrix has important effect on the thermal properties of the nanocomposites. The existence of BaSO 4 nanoparticles enhances the crystallization rate of PET. Besides, it was found that the thermal stability of PET was improved by the addition of the BaSO 4 nanoparticles. 相似文献
12.
Solution blow spinning, SBS, was used to prepare fibrous films of thermoplastic nanocomposites with potential antibacterial properties based on polysulfone, PSF, filled with well dispersed TiO 2 nanoparticles. The PSF/TiO 2 nanocomposites were produced with different nanoparticles content up to 10% by weight. A wide characterization was carried out focusing on the morphology at the nanoscale, roughness, contact angles, and surface free energy. Cell adhesion was studied by inspection by scanning electron microscopy (SEM). A uniform dispersion of the nanofiller was achieved, with the nanoparticles evenly embedded in the polymer along the fibers when they were created during the blow spinning process. TiO 2 content influenced the topography of the films, most likely due to a direct effect on the solvent evaporation rate. The results obtained pointed out that an increase of the surface hydrophobicity as a result of the increased roughness induced by the presence of TiO 2 nanoparticles was the main contribution to the reduction of DH5α Escherichia coli cells adhesion. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1575–1584 相似文献
13.
In this work, a novel sensor for detecting hydrogen peroxide was constructed on the base of nanotubular TiO 2 and platinum nanoparticles. The morphology, structural, and electrochemical properties of the Pt/TiO 2 nanocomposite electrodes were characterized by SEM, XRD and electrochemical methods. With an operating potential of +0.3 V versus Ag/AgCl, the sensor produces catalytic oxidation currents at the nanocomposite electrode, which can be exploited for quantitative determinations. The amperometric signals are linearly proportional to hydrogen peroxide concentration in the range 4×10 ?6 to 1.25×10 ?3 M. The regression equation is I (μA)=0.85 c (mM)+0.16 with a correction coefficient of 0.997. At a signal‐to‐noise ratio of 3, a detection limit of 4.0 μM H 2O 2 can be observed for the nanocomposite electrode. In addition, the sensor has a good stability and reproducibility. The construction process is simple and inexpensive. The results demonstrated that nanotubular TiO 2 exhibits great prospect for developing a class of ideal and novel bioreactors and biosensors. 相似文献
14.
A novel hydrophilic nanocomposite additive(TiO2-g-PNIPAAm) was synthesized by the surface modification of titanium dioxide(TiO2) with N-isopropylacrylamide(NIPAAm) via "graft-from" technique. And the nanocomposite membrane of poly(vinylidene fluoride)(PVDF)/TiO2-g-PNIPAAm was fabricated by wet phase inversion. The graft degree was obtained by thermo-gravimetric analysis(TGA). Fourier transform infrared attenuated reflection spectroscopy(FTIR-ATR) and X-ray photoelectronic spectroscopy(XPS) characterization results suggested that TiO2-g-PNIPAAm nanoparticles segregated on membrane surface during the phase separation process. Scanning electron microscopy(SEM) was conducted to investigate the surface and cross-section of the modified membranes. The water contact angle measurements confirmed that TiO2-g-PNIPAAm nanoparticles endowed PVDF membranes better hydrophlilicity and thermo-responsive properties compared with those of the pristine PVDF membrane. The water contact angle decreased from 92.8° of the PVDF membrane to 61.2° of the nanocompostie membrane. Bovine serum albumin(BSA) static and dynamic adsorption experiments suggested that excellent antifouling properties of membranes was acquired after adding TiO2-gPNIPAAm. The maximum BSA adsorption at 40 °C was about 3 times than that at 23 °C. The permeation experiments indicated the water flux recover ratio and BSA rejection ratio were improved at different temperatures. 相似文献
15.
Titania nano‐sized particles were treated by various amounts of tetraethyl orthosilicate precursor. The extent of grafting was characterized using Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐Vis) spectroscopy techniques, thermal gravimetric analysis, X‐ray fluorescence and zeta potential measurements. Sedimentation behaviour of titanium dioxide (TiO 2) nanoparticles in aqueous solutions was evaluated visually and using a separation analyser. Photocatalytic activity of nanoparticles was studied by photo‐activated degradation reaction of Rhodamine B dyestuff in aqueous solutions. The results showed that grafted particles had acquired enhanced dispersion stability and lower photocatalytic activity in aqueous solutions. Untreated TiO 2 dispersions settled rapidly and sedimentation completed within 24 h through the coagulation mechanism, whereas that of the silica‐treated nanoparticles, depending on the silica content, showed different degrees of stability by flocculation mechanism. Photodebleaching of Rhodamine B in the presence of treated nanoparticles is evident by weaker intensity of UV absorption peak of 554 nm due to lowering concentration of Rhodamine B accompanied with the blue shift in UV absorption peaks. However, untreated TiO 2 nanoparticles showed only weaker intensity of UV absorption peak. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
16.
Polyethylene (PE) composites with titanium oxide (TiO 2) nanoparticles were produced via in situ polymerization representing a novel route to obtain antimicrobial polymeric materials. The TiO 2 nanoparticles synthesized by the sol–gel method were used either as‐synthesized or modified organically with hexadecyltrimethoxysilane (Mod‐TiO 2). These particles were added, together with the catalytic system (formed by a metallocenic catalyst and methylaluminoxane as cocatalyst), directly to the reactor, yielding in situ PE composites with 2 and 8 wt % content of nanofiller. The catalytic polymerization activity presented a slight decrease with the incorporation of the TiO 2 and Mod‐TiO 2 nanoparticles compared to polymerization without filler. Regarding the properties of the composites, crystallinity increased slightly when the different nanofillers were added, and the elastic modulus increased around 15% compared to neat PE. PE/TiO 2 nanocomposites containing 8 wt % of TiO 2 exposed to UVA irradiations presented antimicrobial activity against Escherichia coli. The PE/Mod‐TiO 2 nanocomposite with 8 wt % filler killed 99.99% of E. coli, regardless of light and time irradiation. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
17.
In this study, two types of magnetic polyurethane (PU) elastomer nanocomposites using polycaprolactone (PCL) and polytetramethylene glycol (PTMG) as polyols were synthesized by incorporating thiodiglycolic acid surface modified Fe 3O 4 nanoparticles (TSM‐Fe 3O 4) into PU matrices through in situ polymerization method. TSM‐Fe 3O 4 nanoparticles were prepared using in situ coprecipitation method in alkali media and were characterized by X‐ray diffraction, Fourier Transform Infrared Spectrophotometer, Transmission Electron Microscopy, and Vibrating Sample Magnetometer. The effects of PCL and PTMG polyols on the properties of the resultant PUs were studied. The morphology and dispersion of the nanoparticles in the magnetic nanocomposites were studied by Scanning Electron Microscope. It was observed that dispersion of nanoparticles in PTMG‐based magnetic nanocomposite was better than PCL‐based magnetic nanocomposite. Furthermore, the effect of polyol structure on thermal and mechanical properties of nanocomposite was investigated by Thermogravimetric Analysis and Dynamic Mechanical Thermal Analysis. A decrease in the thermal stability of magnetic nanocomposites was found compared to pure PUs. Furthermore, DMTA results showed that increase in glass transition temperature of PTMG‐based magnetic nanocomposite is higher than PCL‐based magnetic nanocomposite, which is attributed to better dispersion of TSM‐Fe 3O 4 nanoparticles in PTMG‐based PU matrix. Additionally, magnetic nanocomposites exhibited a lower level of hydrophilicity compared to pure PUs. These observations were attributed to the hydrophobic behavior of TSM‐Fe 3O 4 nanoparticles. Moreover, study of fibroblast cells interaction with magnetic nanocomposites showed that the products can be a good candidate for biomedical application. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
18.
Photocatalytic multilayer nanocomposite films composed of anatase TiO 2 nanoparticles and lignosulfonates (LS) were fabricated on quartz slides by the layer‐by‐layer (LBL) self‐assembly technique. X‐ray photoelectron spectroscopy (XPS), UV‐vis spectroscopy and atomic force microscopy (AFM) were used to characterize the TiO 2/LS multilayer nanocomposite films. Moreover, the photocatalytic properties (decomposition of methyl orange and bacteria) of multilayer nanocomposite films were investigated. XPS results indicated that the intensities of titanium and sulfur peaks increased with the LBL deposition process. A linear increase in absorbance at 280 nm was found by UV‐Vis spectroscopy, suggesting that stepwise multilayer growth occurs on the substrate and this deposition process is highly reproducible. AFM images showed that quartz slide was completely covered by TiO 2 nanoparticles when a 10‐bilayer multilayer film was formed. The decomposition efficiency of methyl orange by TiO 2/LS multilayer films under the same UV irradiation time increased linearly with the number of TiO 2 layers, and the results of decomposition of bacteria under UV irradiation showed that TiO 2/LS multilayer nanocomposite films exhibited excellent decomposition activity of bacteria ( Escherichia coil). 相似文献
19.
In the present work, development of neat and nanocomposite polyethersulfone membranes composed of TiO 2 nanoparticles is presented. Membranes are fabricated using nonsolvent phase inversion process with the objective of improving antifouling, hydrophilicity, and mechanical properties for real and synthetic produced water treatment. Membranes are characterized using scanning electron microscopy, Fourier‐transform infrared, contact angle, porosity measurement, compaction factor, nanoparticles stability, and mechanical strength. The performance of prepared membranes was also characterized using flux measurement and oil rejection. Fourier‐transform infrared spectra indicated that noncovalence bond formed between Ti and polyethersulfone chains. The contact angle results confirmed the improved hydrophilicity of nanocomposite membranes upon addition of TiO 2 nanoparticles owing to the strong interactions between fillers and water molecules. The increased water flux for nanocomposite membranes in comparison with neat ones can be due to coupling effects of improved surface hydrophilicity, higher porosity, and formation of macrovoids in the membrane structure. The membrane containing 7 wt% of TiO 2 nanoparticles was the best nanocomposite membrane because of its high oil rejection, water flux, antifouling properties, and mechanical stability. The pure water flux for this membrane was twice greater than that of neat membrane without any loss in oil rejection. The hydrophilicity and antifouling resistance against oil nominates developed nanocomposite membranes for real and synthetic produced water treatment applications with high performance and extended life span. 相似文献
20.
Herein, a peapod‐like TiO 2/carbon nanocomposite has successfully been synthesized by a rational method for the first time. The novel nanostructure exhibits a distinct feature of TiO 2 nanoparticles encapsulated inside and the carbon fiber coating outside. In the synthetic process, H 2Ti 3O 7 nanotubes serve as precursors and templates, and glucose molecules act as the green carbon source. With the alliciency of hydrogen bonding between H 2Ti 3O 7 and glucose, a thin polymer layer is hydrothermally assembled and subsequently converted into carbon fibers through calcinations under an inert atmosphere. Meanwhile, the precursors of H 2Ti 3O 7 nanotubes are transformed into the TiO 2 nanoparticles encapsulated in carbon fibers. The achieved unique nanocomposites can be used as excellent anode materials in lithium‐ion batteries (LIBs) and photocatalytic reagents in the degradation of rhodamine B. Due to the synergistic effect derived from TiO 2 nanoparticles and carbon fibers, the obtained peapod‐like TiO 2/carbon cannot only deliver a high specific capacity of 160 mAh g ?1 over 500 cycles in LIBs, but also perform a much faster photodegradation rate than bare TiO 2 and P25. Furthermore, owing to the low cost, environmental friendliness as well as abundant source, this novel TiO 2/carbon nanocomposite will have a great potential to be extended to other application fields, such as specific catalysis, gas sensing, and photovoltaics. 相似文献
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