共查询到20条相似文献,搜索用时 0 毫秒
1.
《Ceramics International》2017,43(6):5351-5355
In this work, TiO2‒Ag nanocomposite thin films were fabricated for the first time via simultaneous plasma-enhanced chemical vapor deposition and physical vapor deposition of TiO2 and Ag nanoparticles in the gas-phase, respectively. The presence of Ag nanoparticles in the prepared nanocomposites has been confirmed using transmission electron microscopy and energy dispersive X-ray spectrometry techniques. The obtained electron microscopy images showed that the average size of TiO2‒Ag nanoparticles was larger than that of pristine TiO2. Moreover, the temperature of the anatase transformation into the rutile phase was decreased due to the presence of Ag nanoparticles in the TiO2 matrix, while the photocatalytic activity of the produced nanocomposite (estimated by studying the degradation of methylene blue aqueous solution under UV irradiation) was 35% greater than that of pristine TiO2. Therefore, the addition of Ag nanoparticles into the TiO2 matrix significantly affected the morphology, phase transformation temperature, and photocatalytic performance of the fabricated material. 相似文献
2.
Ming Li Maojun Zheng Tao Zhou Changli Li Li Ma Wenzhong Shen 《Nanoscale research letters》2012,7(1):675
Ordered CuIn(1−x)GaxSe2 (CIGS) nanopore films were prepared by one-step electrodeposition based on porous anodized aluminum oxide templates. The as-grown film shows a highly ordered morphology that reproduces the surface pattern of the substrate. Raman spectroscopy and X-ray diffraction pattern show that CIGS nanopore films had ideal chalcopyrite crystallization. Energy dispersive spectroscopy reveals the Cu-Se phases firstly formed in initial stage of growth. Then, indium and gallium were incorporated in the nanopore films in succession. Cu-Se phase is most likely to act as a growth promoter in the growth progress of CIGS nanopore films. Due to the high surface area and porous structure, this kind of CIGS films could have potential application in light-trapping CIGS solar cells and photoelectrochemical water splitting. 相似文献
3.
This study describes a green method for preparing all-cellulose nanocomposites through a dissolution and regeneration process. Cotton linter pulp was dissolved in 7 wt % NaOH/12 wt % urea aqueous solution precooled to −12°C. Self-assembly of cellulose molecules into nanostructured cellulose fiber is achieved by using water addition and controlling the temperature to regenerate cellulose. By changing the microenvironment of the cellulose solution, the morphology of the nanostructured cellulose fibers and the mechanical properties of the regenerated cellulose films can be tuned. Then, a series of regenerated cellulose films have been prepared and characterized from various aspects. Compared with other all-cellulose films in the literature, the regenerated all-cellulose nanocomposite films prepared in this work exhibited good optical transparency, thermal stability, and excellent tensile strength (up to 135 MPa) when the regeneration temperature was adjusted to 50°C. This work provided a green and promising approach to prepare high-performance and environmentally friendly all-cellulose nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46925. 相似文献
4.
Optimization of operational conditions for the polymerization of propylene with Ziegler–Natta catalyst was carried out via
RSM. Response surface methodology (RSM) based on a three-level, four-variable Box–Behnken design was used to evaluate the
interactive effects of reaction conditions such as reaction temperature (60–80 °C), monomer pressure (5–8 bar), hydrogen volume
(130–170 mL), and cocatalyst to catalyst ratio (Al/Ti, 340–500) on the catalyst activity and melt flow rate (MFR). The optimum
reaction conditions derived via RSM were: temperature 70 °C, pressure 8 bar, hydrogen volume 151 mL, and cocatalyst to catalyst
ratio 390. The experimental catalyst activity and MFR were 8 g polypropylene/mg catalyst and 10.9 g/10 min, respectively,
under optimum conditions. Optimum values were determined from process cost point of view and offered better operational conditions. 相似文献
5.
Tarun Pal Singh Geeta Chauhan Ravi Kant Agrawal S. K. Mendiratta 《Iranian Polymer Journal》2018,27(11):861-879
In this study, Box–Behnken response surface experimental design of response surface methodology (RSM) was adopted to investigate the simultaneous effects of tomato puree (1–3% w/v), casein (0.4–0.8% w/v) and drying time (10–12 h) on the physical and optical properties of a bio-composite film. Analysis of variance (ANOVA) showed that the experimental data was well-explained by the different models with high coefficient of determination (R2?>?0.90). The second-order polynomial models were fitted to all the response variables and three-dimensional response surface plots and equations were analyzed. It was found that all the process variables significantly affected (P?<?0.05) the response variables either linearly or quadratically, whereas the “Lack of Fit” was non-significantly relative to the pure error. On the basis of the ranges of different responses, a total of nine solutions were suggested, out of which, the film with 2.12% w/v tomato puree level, 0.59% w/v casein level and 11.99 h drying time was selected. At this optimum point, thickness, moisture, solubility, moisture absorption rate, water vapor transmission rate, density, transparency, hue angle, chroma value and whiteness index were found to be 0.143 mm, 24.49%, 77.69%, 10.22%, 0.03 g/cm2 t, 1.472 g/mL, 40.72%, 78.70, 11.60 and 64.99, respectively, with a desirability value of 0.61. It can be concluded that the developed films with desirable characteristics can be successfully prepared and effectively applied in the food packaging industry. 相似文献
6.
Superhydrophobic and superoleophilic cotton fabric was successfully prepared with fluorinated silica sol via a facile sol–gel method. A fluorinated polymeric sol–gel precursor (PHFBMA-MTS) was synthesized via free-radical polymerization by using hexafluorobutyl methacrylate (HFBMA) in the presence of (3-mercaptopropyl)trimethoxysilane (MTS) as the chain transfer agent, which led to the formation of fluoropolymer with alkoxysilane end groups. Then the fluorinated silica sol was prepared by introducing PHFBMA-MTS as the co-precursor of tetraethylorthosilicate (TEOS) in the sol–gel process with ammonium hydroxide as the catalyst, which was then used to fabricate superhydrophobic and superoleophilic fabric coatings through a simple dip-coating method. The coated fabrics showed superhydrophobic property with a high water contact angle of 154.1° and superoleophilic property with an oil contact angle of 0°. Moreover, the coated fabrics still kept superhydrophobicity even after ultrasonic treatment, as well as for organic solutions, acidic solutions. Thus, the coated fabrics were successfully applied to separate oil–water mixture with separation efficiency up to 99.8%. More importantly, the separation efficiency had no significant change after 20 cycles of oil–water separation. These present a simple, low-cost, and durable approach to achieve industrialized application of coated fabrics in oil–water separation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47005. 相似文献
7.
《Ceramics International》2020,46(12):20068-20080
In this study, Al2O3–TiC composites synergistically reinforced with multi-walled carbon nanotubes (MWCNTs) and graphene nanoplates (GNPs) were prepared via spark plasma sintering (SPS). The effects of the MWCNT and GNP contents on the phase composition, mechanical properties, fracture mode, and toughening mechanism of the composites were systematically investigated. The experimental results indicated that the composite grains became more refined with the addition of MWCNTs and GNPs. The nanocomposites presented high compactness and excellent mechanical properties. The composite with 0.8 wt% MWCNTs and 0.2 wt% GNPs presented the best properties of all analysed specimens, and its relative density, hardness, and fracture toughness were 97.3%, 18.38 ± 0.6 GPa, and 9.40 ± 1.6 MPa m1/2, respectively. The crack deflection, bridging, branching, and drawing effects of MWCNTs and GNPs were the main toughening mechanisms of Al2O3–TiC composites synergistically reinforced with MWCNTs and GNPs. 相似文献
8.
Gabriela Leticia de Jesus Camila Baldasso Nilson Romeu Marcílio Isabel Cristina Tessaro 《应用聚合物科学杂志》2020,137(42):49282
In this study, the objective was to prepare and characterize films with different concentrations of demineralized whey (3–10%) and gelatin (1–3%) containing glycerol (10–70%) as a plasticizer and chitosan or nanochitosan as an additive. Mechanical properties, thickness, grammage, opacity, moisture content, water, and ethanol solubilities of the obtained films were determined. The formation of films without glycerol and gelatin was not possible. A higher gelatin concentration led to more desirable mechanical properties. Thickness, grammage, opacity, and moisture content remained almost constant after increasing gelatin concentration. Heightening glycerol concentrations raised water and ethanol solubility. Despite presenting high water solubility, the films showed low ethanol solubility. The formulation containing whey (3%), glycerol (20%), gelatin (3%), and chitosan (0.1%) resulted in the highest performing film concerning physical and mechanical aspects. Through Fourier transform infrared spectroscopy analysis, it was possible to observe the displacement and the frequency reduction of the band near 3,300 cm−1, revealing different protein interactions. It indicates that hydrogen bonds occur between the amino group and OH of the protein molecules reducing film hydrophilicity. Contact angle measurements also showed a less hydrophilic character. The films present the potential to prolong the shelf life of food, such as dairy products. 相似文献
9.
《Journal of the European Ceramic Society》2022,42(4):1348-1353
Transparent γ-AlON undoped and doped with one of eight rare earth elements were fabricated by hot pressing at 1850 °C. After characterizing the fundamental physical properties of sintered γ-AlON, the photoluminescence spectra of γ-AlON:Sm and γ-AlON:Yb were examined further because only these samples showed a color under visible light because of the absorbance of a certain wavelength. γ-AlON:Sm exhibited a red emission with emission peaks at 688, 701, and 729 nm, while γ-AlON:Yb exhibited a white emission due to the two broad emission peaks at 438 and 575 nm. γ-AlON:Yb revealed a possible application to UV-excited phosphor-converted white-light-emitting diodes because of its emission characteristics. The schematic crystal structure of the rare-earth-doped γ-AlON and the CIE chromaticity diagram were provided to understand the photoluminescence behavior of γ-AlON:Sm and γ-AlON:Yb. 相似文献
10.
Fernando G. Torres Junior Arroyo Ricardo Alvarez Sol Rodriguez Omar Troncoso Daniel López 《Polymer-Plastics Technology and Engineering》2019,58(8):889-902
The effect of carboxymethylation and NH4I incorporation on the molecular dynamics of carrageenan films was studied. Broadband Dielectric Spectroscopy (BDS) assessed the presence of α and β relaxation processes. The effect of NH4I content was analyzed using the Havriliak-Negami model and parameterizing the temperature dependence of the relaxation times according to the Vogel-Fulcher-Tammann-Hesse (VFTH) equation. The glass transition temperature was found to decrease with the increase of NH4I content. These results suggest that carboxymethylation and the salt doping treatment increase the molecular mobility of NH4+ ions, making the films suitable for the development of solid electrolytes for energy storage applications. 相似文献
11.
Mun Teng Soo Go Kawamura Hiroyuki Muto Atsunori Matsuda Zainovia Lockman Kuan Yew Cheong 《Ceramics International》2013
Mesoporous zirconia (ZrO2) thin films were prepared by dip-coating via Pluronic P123 templated sol–gel route. ZrOCl2·8 H2O was used as zirconium (Zr) precursors. Annealing of as-coated ZrO2 thin films is important in order to stiffen the respective films and to remove the Pluronic P123. The mesoporous structure and crystallite size of ZrO2 were characterized systematically by field-emission scanning electron microscope (FESEM), both low- and wide-angle X-ray diffraction, thermal analysis technique and Brunauer–Emmett–Teller method. At annealing temperature of 400 °C, amorphous ZrO2 was transformed into tetragonal phase of ZrO2 (t-ZrO2). At 450 °C, t-ZrO2 and monoclinic phase of ZrO2 (m-ZrO2) were obtained. By altering heating rate during annealing, volume fraction of t-ZrO2 and m-ZrO2 was changed. FESEM images showed that disordered mesostructures of ZrO2 were formed after annealing. The surface area of mesoporous ZrO2 obtained ranges from 54.33 to 93.39 m2/g. 相似文献
12.
Pradum Pundlikrao Ige Pravin Rajput Chandrakantsingh Pardeshi Rajendra Kawade Bramhanand Swami Hitendra Mahajan Pankaj Nerkar Veena Belgamwar Sanjay Surana Surendra Gattani 《Iranian Polymer Journal》2013,22(12):911-921
Polymeric mucoadhesive pellets of nifedipine were designed using computer software and they were prepared by extrusion-spheronization using HPMC K15M and κ-carrageenan with microcrystalline cellulose. A randomized rotatable two factor central composite design was applied for assessment of influence of two independent variables such as concentration of κ-carrageenan and HPMC K15M on dependent variables. Pellets were characterized by FTIR, DSC, SEM, flow properties, particle size, abrasion resistance, sphericity, drug content, percent production yield, in vitro drug release, ex vivo mucoadhesion, stability studies and similarity factor. The optimized formulation was selected based on criteria of sphericity nearest to 1.0 with maximum cumulative drug release percentage. Formulation NF6 exhibited sufficient porous spheres, free flowing and smooth surface mucoadhesion of 91.34 % and drug content 98.22 ± 0.37 %. Kinetic modeling revealed that the formulation followed the Higuchi model and showed the Quassi-Fickian drug release mechanism. The similarity factor, F2 value, was found to be 74 ± 6 and there was no significant change in drug content and ex vivo mucoadhesion after 90 days at 40 ± 2 °C, and 75 ± 5 % RH clearly indicated the optimized batch NF6 was stable. Thus, it can be concluded that use of κ-carrageenan, microcrystalline cellulose and HPMC K15M at the 20:35:10 w/w ratio could provide an effective carrier for enhancement of sphericity and sustained release of matrix pellets. 相似文献
13.
The poor flexibility, low toughness and thermal stability have restricted the applications of degradable poly(lactic acid) bioplastic. The introduction of deoxyribonucleic acid, whey protein or collagen with helical structures, which include numerous intermolecular hydrogen bonds, can produce changes in mechanical and thermal properties of poly(lactic acid) materials. Due to the presence of more –C?=?O and –NH groups with strong hydratability, different composites exhibited a higher heat resistance compared with the neat poly(l-lactic acid). Moreover, for collagen/poly(l-lactic acid) composites, the tensile strength and elongation at break were increased by 88.6 and 154.9% compared with the neat poly(l-lactic acid), respectively. The results provide a basis for the design of novel poly(lactic acid)-based composites and can expand the application areas of materials, including plastic films, taker-bags, textiles and so on. 相似文献
14.
This study focuses on the optimization of polyethersulfone (PES) hollow fiber membranes fabricated with the phase inversion method. A Box–Behnken experimental design was employed with three different PES concentration ratios (11, 14, 17 wt.%), three polyvinylpyrrolidone (PVP) molecular weight ratios (K30/K90 ratios of 6:0, 3:3, 0:6 wt.%), three different bore fluid (BF) composition ratios (water/alcohol ratios of 20:80, 60:40, 100:0), and three different air gap values (24, 37, and 50 cm). The results were analyzed in terms of pure water permeability (PWP) and porosity as optimization parameters using response surface methodology and the classification and regression tree (CART) model. ANOVA results revealed significant effects of PES concentration, PVP molecular weight, and BF composition on the outcomes. After optimization, the maximum PWP and the maximum porosity were obtained as 360.15 L/m2 h bar, 60.57%, respectively. The CART model achieved sufficient accuracy in classifying samples. 相似文献
15.
《Ceramics International》2016,42(4):5141-5147
All porous materials have a common limitation which is lack of strength due to the porosity. In this study, two different methods have been used to produce porous β-tricalcium phosphate (β-TCP) scaffolds: liquid-nitrogen freeze casting and a combination of the direct-foaming and sacrificial-template methods. Among these two methods, porous β-TCP scaffolds with acceptable pore size and compressive strength and defined pore-channel interconnectivity were successfully fabricated by the combined direct-foaming and sacrificial-template method. The average pore size of the scaffolds was in the range of 100–150 µm and the porosity was around 70%. Coating with 4 wt% alginate on porous β-TCP scaffolds led to higher compressive strength and low porosity. In order to make a chemical link between the β-TCP scaffolds and the alginate coating, silane coupling agent was used. Treated β-TCP scaffold showed improvements in compressive strength of up to 38% compared to the pure β-TCP scaffold and 11% compared to coated β-TCP scaffold. 相似文献
16.
Morteza Ahmadi Mohammad Reza Moghbeli Mahmood M. Shokrieh 《Iranian Polymer Journal》2012,21(12):855-868
Glassy unsaturated polyester (UP) resin was reinforced using an organically modified montmorillonite (OMMT) and toughened with core?Cshell rubber (CSR) particles. The nanostructure, morphology, and deformation mechanism of composite specimens were studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and reflected optical microscopy (ROM). An intercalated nanostructure with partial exfoliation was observed in the UP reinforced by various amounts of OMMT. Locally clustered but globally good CSR particle dispersion in the UP matrix was evident in UP toughened with 5 and 10 wt% CSR particles. Simultaneous presence of OMMT and CSR particles in UP/OMMT/CSR hybrid composites was found to cause partial phase separation with bigger rubber particle agglomerates and lower clay-intergallery height increase. The effects of OMMT and CSR contents on volume shrinkage, impact fracture energy, fracture toughness, and compressive yield strength of UP were investigated. The introduction of OMMT of up to 3?wt% into the UP matrix lowered volume shrinkage to some extent, while further addition increased the shrinkage slightly. In the hybrid nanocomposites, the volume shrinkage decreased to a minimum level of 5.2?% with increases in OMMT level. The impact fracture energy of UP improved with increasing the OMMT level of up to 3?wt%, whereas its further addition decreased the impact fracture energy slightly due to the clay particle agglomeration. The hybrid composites with OMMT level below 3?wt% showed higher impact fracture energy compared to the reinforced UP specimens with the same OMMT levels. Interestingly, a synergism in the fracture toughness (K IC) was observed in the hybrid composite containing 1?wt% OMMT and 10?wt% CSR particles. The presence of OMMT as reinforcement in the hybrid composites could compensate the lowering of the compressive yield strength caused by low-modulus CSR particles. The clay?Crubber particle interaction in the hybrid systems seems to increase the threshold of shear deformation of the UP matrix to some extent. 相似文献
17.
Hydrogel beads are emerging as alternate adsorbent material for the batch or continuous column treatment of dye wastewater. Polysaccharide-based gel beads are preferred for their uniform shape and size, large specific surface area, and easy separation by filtration and subsequent reuse. In this work, we prepare and rheologically characterize UV-active κ-carrageenan/TiO2 beads for the adsorption and degradation of dyes. The 3–4 mm sized nanocomposite beads are formed by the extrusion of κ-carrageenan/TiO2 gel solution in salt solutions. The maximum increase in modulus was observed with the addition of 1% w/v TiO2 to κ-carrageenan and subsequent crosslinking with mixed salt of KCl and CaCl2. κ-carrageenan/TiO2 beads crosslinked by mixed salt of KCl and CaCl2 have higher adsorption capacity, as compared to beads crosslinked with single salt of KCl. The kinetic study indicated the chemisorption of Methylene Blue on the bead surface. κ-carrageenan/TiO2 beads showed higher degradation for Methylene Blue and Nile Blue A than Rhodamine B in 5 and 50 ppm each multicomponent dye systems under UV irradiation. The κ-carrageenan/TiO2 beads could form a porous column for the selective adsorption of positively charged dyes from a multicomponent dye system. 相似文献
18.
《Ceramics International》2020,46(17):27000-27009
Cubic silicon carbide (3C–SiC) is an excellent protective film on graphite and has been fabricated via laser chemical vapor deposition (LCVD) with an extremely high deposition rate by our research group. To understand comprehensively its growth behavior, the polycrystalline 3C–SiC thick films with the preferred orientation of <111> and <110> were characterized by diverse measurements, especially electron back-scatter diffraction (EBSD). Along the growth direction of the <110>-oriented 3C–SiC, the microstructure changed from equiaxed grains to elongated grains with <111> orientation, and eventually the <110>-oriented columnar grains. The stacking faults in the <110>-oriented 3C–SiC could be marked as <11–20>-oriented 6H–SiC. On the other hand, in the <111>-oriented 3C–SiC films, the microstructure changed from mainly equiaxed grains to large columnar grains. The high-density stacking faults in <111>-oriented 3C–SiC films may lead to the identification of the nominal 2H, 4H and 6H polytypes by Raman spectra and EBSD. The (0001) planes of 2H-, 4H–SiC are perpendicular to the growth direction, while that of 6H–SiC are parallel. 相似文献
19.
M. Yousefi P. Alizadeh B. Eftekhari Yekta F. Molaie N. Ghafoorian M. Montazerian 《Ceramics International》2009
Glass–ceramic composites in the SiO2–CaO–MgO–(Na2O) system, reinforced with 5, 10 and 20 wt.% aluminum titanate were synthesized by pressureless sintering. Optimum sintering temperatures with maximum relative density were determined for each composition. The composites were fired above the crystallization peak temperature of glass–ceramic. Mechanical properties of glass–ceramic and sintered composites, such as fracture toughness, flexural strength and Vickers microhardness, were investigated. The sintered composites were characterized by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the composite containing 10 wt.% aluminum titanate has desirable behavior in comparison to the base glass–ceramic and the other compositions. It seems that crack deflection by aluminum titanate particles is the prevalent mechanism for improving mechanical characteristics. 相似文献
20.
Microcapsules containing neem seed oil (NSO) were prepared using complex coacervation technique and employing gelatin A and κ-carrageenan polyelectrolyte complex. The yield of the coacervate was dependent on the ratio of the two polymers and on the pH of the medium. Viscosity and turbidity measurements were carried out in order to support the ratio of the two polymers that produced the highest yield. The encapsulation efficiency and the release rates of NSO were dependent on the amount of crosslinker, oil loading and polymer concentration. Scanning electron micrographs showed the formation of free flowing spherical microcapsules. The size of microcapsules increased with the increase of the concentration of the polymer. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry study showed that there was no significant interaction between NSO and carrageenan–gelatin complex. 相似文献