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1.
Polyurethane-based coatings reinforced by ZnO nanoparticles (about 27 nm) were prepared via solution blending. The ZnO/PU films and coats were fabricated by a simple method of solution casting and evaporation. The mechanical properties of the films were investigated by a universal material test, and the abrasion resistance of the prepared coats was evaluated by a pencil-abrasion-resistance tester. It was found that significant improvement of the PU films in Young’s modulus and tensile strength was achieved by incorporating ZnO nanoparticles up to 2.0 wt%, and that the abrasion resistance of the PU coats was greatly enhanced due to the addition of ZnO nanoparticles. Moreover, the antibacterial property test was carried out via the agar dilution method and the result indicated that PU films doped with ZnO nanoparticles showed excellent antibacterial activity, especially for Escherichia coli.  相似文献   

2.
A series of polypropylene carbonate (PPC)/ZnO nanocomposite films with different ZnO contents were prepared via a solution blending method. The morphological structures, thermal properties, oxygen permeability, water sorption, and antibacterial properties of the films were investigated as a function of ZnO concentration. While all of the composite films with less than 5 wt % ZnO exhibited good dispersion of ZnO in the PPC matrix, FTIR and SEM results revealed that solution blending did not lead to a strong interaction between PPC and unmodified ZnO. As such, poor dispersion was induced in the composite films with a high ZnO content. By incorporating inorganic ZnO filler nanoparticles, the diffusion coefficient, water uptake in equilibrium, and oxygen permeability decreased as the content of ZnO increased. The PPC/ZnO nanocomposite films also displayed a good inhibitory effect on the growth of bacteria in the antimicrobial analysis. The enhancement in the physical properties achieved by incorporating ZnO is advantageous in packaging applications, where antimicrobial and environmental‐friendly properties, as well as good water and oxygen barrier characteristics are required. Furthermore, UV light below ~ 350 nm can be efficiently absorbed by incorporating ZnO nanoparticles into a PPC matrix. ZnO nanoparticles can also improve the weatherability of a PPC film. In future research, the compatibility and dispersion of the PPC matrix polymer and the inorganic ZnO filler nanoparticles should be increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.  相似文献   

3.
Nano‐ZnO/high‐density polyethylene (HDPE) composite films were prepared via melt blending and a hot compression‐molding process. The properties, including ultraviolet absorption, mechanical and antibacterial properties of the films, and plasticizing behavior of the composites, were investigated. The results show that the absorbance in the ultraviolet region of the HDPE films was enhanced after the addition of modified nano‐ZnO to the HDPE matrix. Also, we found that improvement in the HDPE films of the tensile strength and elongation at break was achieved by the incorporation of modified ZnO nanoparticles up to 0.5 wt % in contrast with the original nano‐ZnO/HDPE composite films. Antibacterial testing was carried out via plate counting, and the results indicate that the HDPE films doped with modified ZnO nanoparticles showed favorable antibacterial activity, especially for Staphylococcus aureus. However, the low doped content of modified nano‐ZnO in the HDPE matrix made the balance torque of the composites increase slightly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

4.
聚氨酯/纳米氧化锌复合材料研究进展   总被引:1,自引:0,他引:1  
综述了聚氨酯/纳米氧化锌复合材料的制备方法及研究进展。介绍了纳米氧化锌复合材料力学性能、抗静电性能、紫外屏蔽性能、耐磨与抗腐蚀性能和阻尼减振性能及应用。指出聚氨酯/纳米氧化锌复合材料存在的问题及发展方向。  相似文献   

5.
In this research, ZnO nanoparticles (ZnO NPs) and Carbon Quantum Dots-decorated ZnO nanoparticles (ZnO/CQDs NCs) were prepared via different procedures and precursors. Soya chunk was applied as a source of carbon for the preparation of CQDs. Crystalline structure, purity, size, and morphological properties of products were investigated via X-ray diffraction (XRD) analysis, energy dispersive spectroscopy (EDS), Transmission Electron Microscopy (TEM), FT-IR, and Scanning Electron Microscopy (SEM) respectively. Findings showed that homogeneity, size, and morphological properties of products can be intensively affected via different precursors and procedures. From the homogeneity, size, and morphological point of view, the hydrothermal route, ammonia, 5 h, and 180 °C were the optimum procedure, pH adjuster, temperature, and time respectively. Optimum product was applied for carrying out minimum inhibitory concentration (MIC) and Agar disk-diffusion tests against various microorganisms. Results demonstrated that prepared ZnO NPs have maximum antibacterial activity against Staphylococcus aureus (19.53 μg/ml) and ZnO/CQDs NCs have no inhibitory effect against tested microorganisms. For ZnO NPs, the disk diffusion test proved that the highest growth inhibition zone was related to Staphylococcus aureus (15 mm). The presence of CQDs in ZnO/CQDs NCs reduces the inhibitory effect of ZnO NPs intensively.  相似文献   

6.

The present work addresses a facile synthesis of Indium doped zinc oxide (IZO) cellulose acetate nanocomposite membrane. The membrane was prepared by casting method. Various weights of In:ZnO nanoparticles were added to solution formed by dissolution of cellulose acetate granules in acetone. The harvested membrane, after acetone evaporation, was characterized by various techniques including X ray diffraction, scanning electron microscopy, energy dispersive X ray and elemental mapping, Fourier transform infrared spectroscopy. The results show that the In:ZnO nanoparticles are well embedded in the cellulose acetate host matrix. The elemental mapping reveals that the nanoparticles are uniformly distributed. The optical characterization reveals the reduction of the transmittance in the UV (A and B range) of the CA/IZO composite with increasing the weight of the added IZO powder. This reduction was attributed to ZnO UV absorption. No noticeable peak assigned to ZnO bond are observed. However, IR peaks are shifted towards the higher wavenumber due to the change of the bonds environment with including IZO in the CA matrix. The antibacterial action of the synthetized nanocomposite membranes was tested against Escherichia coli (E. coli). Staphylococcus aureus (S. aureus). The assay results have shown that the membrane has no activity against (E. coli). In contrary, the synthetized membrane exhibits an interesting antibacterial activity against S. aureus. The inhibition region varies from 6 to 15 mm with increasing the weight ratio of filler. A zone of inhibition (ZOI) of 18 mm was observed for the membrane prepared with 30% wt. of In:ZnO. We noticed that the ZOI radius increases with the added weight of IZO. Due the settling down of the nanoparticles only one face of the membrane exhibits an antibacterial activity.

  相似文献   

7.
Nanosized ZnO modified by 2-aminoethyl-3-aminopropyltrimethoxysilane (APS) was prepared using the precipitation method. Modified nano ZnO by silane (ZnO-APS) was characterized by XRD, SEM, TEM and UV–vis measurements. The degradation of the polyurethane coating, the polyurethane coatings containing 0.1 wt% nano ZnO and the polyurethane coatings containing nano ZnO-APS at two concentrations (0.1 and 0.5 wt%) during QUV test was evaluated by gloss measurement and electrochemical impedance spectroscopy. The coating surface after QUV test was observed with SEM. The results show that nano ZnO-APS has spherical structure with particle size around 10–15 nm. Nano ZnO improved the UV resistance of the PU coating and surface treatment by APS enhanced the effect of nano ZnO. The presence of nano ZnO-APS at 0.1 wt% concentration significantly improved the UV resistance of polyurethane coating.  相似文献   

8.
This study describes the effects of the addition of inorganic nanosized UV absorbers on physico-mechanical and thermal properties of an exterior commercial acrylic-based waterborne stain for wood. Electronic microscopy and water vapor (WV) permeability measurements were performed to characterize the free films of the acrylic stain and resulting nanocomposite coatings. An accelerated weathering method was used to evaluate aging behavior of the coatings on wood through appearance, Tg, abrasion resistance, adhesion strength, hardness and Young's modulus changes. In addition to improving the protection against UV, the doped TiO2 and silica-coated ZnO nanoparticles in powder form have improved the abrasion resistance and barrier effect against water vapor diffusion of the acrylic stain. For most of nanocomposite coatings, the addition of ZnO hydrophilic nanoparticles in predispersed form has resulted in a decrease in WV permeability, while the adhesion strength and abrasion resistance of those coatings were negatively affected. The addition of ZnO nanoparticles has decreased the Tg of the acrylic stain. Finally, the accelerated weathering has induced an increase in Tg, hardness, Young's modulus (stiffness) and an increase in apparent adhesion strength and abrasion resistance of the coatings. The Tg values of the aged nanocomposite coatings were lower than that of unmodified acrylic stain.  相似文献   

9.
The objective of this study was to develop a new class of bimetallic ZnO/Ag embedded polyurethane multi-functional nanocomposite by a straightforward approach. Bimetallic nanomaterials, composed of two unlike metal elements, are of greater interest than the monometallic materials because of their improved characteristics. In the present study the bimetallic composite was prepared using sol–gel via the facile electrospinning technique. The utilized sol–gel was composed of zinc oxide, silver and poly(urethane). The physicochemical properties of as-spun composite mats were determined by X-ray diffraction pattern, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The antibacterial activity was tested using Escherichia coli as model organism. The antibacterial test showed that ZnO:Ag/polyurethane composite possesses superior antimicrobial activity than pristine PU and ZnO/PU hybrids. Furthermore, our results illustrate that the synergistic effect of ZnO and Ag resulted in the advanced antimicrobial action of bimetallic ZnO/Ag composite mat. The viability and proliferation properties of NIH 3T3 mouse fibroblast cells on the ZnO:Ag/polyurethane composite nanofibers were analyzed by in vitro cell compatibility test. Our results indicated the non-cytotoxic behavior of bimetallic ZnO:Ag/polyurethane nanofibers towards the fibroblast cell culture. In summary, novel ZnO:Ag/polyurethane composite nanofibers which possess large surface to volume ratio with excellent antimicrobial activity were fabricated. The unique combination of ZnO and Ag nanoparticles displayed potent bactericidal effect due to a synergism. Hence the electrospun bimetallic composite indicates the huge potential in water filtration, clinical and biomedical applications.  相似文献   

10.
We describe polyurethane (PU)/silica hybrids (PSHs) prepared through hydrolysis and condensation reactions of tetraethoxysilane (TEOS) with or without methyltriethoxysilane (MTES) in the presence of polyurethane dispersion, which were subsequently incorporated into waterborne polyurethane (WPU) to prepare composites. The effects of the solid mass ratio of PSHs/WPU on the particle size of composite emulsions, the dispersion of silica nanoparticles in composite films, and the hardness and abrasion resistance of the corresponding films were examined. Composite emulsions possess a nanoscale particle size when incorporated with PSHs prepared using TEOS and MTES as precursors, and are superior to those with PSHs prepared using TEOS alone. Transmission electron microscopy revealed that silica nanoparticles had a uniform distribution in the polymer matrix and agglomerates could be almost completely avoided through in situ modification of silica with Si-CH3 groups in the polyurethane dispersion. Composite films prepared with this method exhibited a superior hardness and abrasion resistance even at a lower silica content compared with that containing unmodified silica. In particular, optical microscopy and scanning probe microscopy observations demonstrated wear behavior differences among these composite films from the macro- and nanoscale viewpoints, respectively. It is proved that abrasive wear occurs, and surface morphology studies are in accordance with the results of abrasion resistance tests.  相似文献   

11.
We report the synthesis and characterization of ZnO nanoparticles prepared via pulse combustion-spray pyrolysis (PC-SP) at a high rate. Instead of using an ultrasonic nebulizer as the atomizer during PC-SP synthesis, a two-fluid nozzle was used to enhance the production rate. A high production rate was achieved by the use of a two-fluid nozzle, which efficiently generated droplets in large quantities, and by controlling the rate of precursor flow. ZnO nanoparticles were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectroscopy. The prepared ZnO nanoparticles were spherical and highly crystalline with an average size of 15.6 nm. In addition, high UV-light absorption and visible-light transparency properties were successfully obtained for a dispersion of ZnO nanoparticles in glycerol. The high UV-blocking capacity of the ZnO particle dispersion makes the dispersion potentially useful in cosmetic applications.  相似文献   

12.
In this study, we used a solution casting method to prepare gellan gum (G)-based ternary nanocomposite films containing polyacrylamide (P) and zinc oxide (ZnO) nanoparticles. All composites were prepared using the chemical cross-linker N,N-methylenebisacrylamide. The nanocomposites were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, and scanning electron microscopy. Attenuated total reflectance FTIR revealed strong hydrogen bonding interactions among gellan gum, polyacrylamide, and ZnO, which enhanced the physiochemical, thermal, and mechanical properties of the GPZnO nanocomposites. The addition of ZnO nanoparticles increased the glass transition temperature (Tg: 181.8–196.3°C), thermal stability (T5%: 87.8–96.5°C), and char yield (23.9–29.1%) of the GP composite films, as well as their the tensile strength (from 33.5 to 43.8 MPa) and ultraviolet (UV) blocking properties (~99.2% protection against UVB [280–320 nm]). ZnO significantly influenced the rheological properties of the GP composite. The prepared GP and GPZnO nanocomposites exhibited shear thinning behavior and their viscosities decreased when there is an increase in shear rate. Storage and loss modulus increased with frequency with the addition of ZnO nanoparticles. The GPZnO films exhibited reduced hydrophilicity, moisture content, and water barrier properties compared with the GP film. The GPZnO nanocomposites exhibited effective antimicrobial activity against six different pathogens. The prepared GPZnO films could be useful in biodegradable packaging applications.  相似文献   

13.
Hybrid particles of polyurethane (PU) containing a number of small poly(methyl methacrylate) (PMMA) nanoparticles inside were prepared using glycidyl methacrylate (GMA) monomer as a linker between PU and PMMA; the resulting polymers were poly (urethane‐glycidyl methacrylate‐methyl methacrylate) (PUGM). It was found that the average particle size (Dp) of the PU particles decreased by the inclusion of PMMA particles possibly owing to the low‐solution viscosity of PU. However, Dp of the PUGM hybrid particles increased with increasing the number of covalent bonds between PMMA and PU, which might be due to decreasing the amount of ionic groups per PU chain. Subsequently, the tensile properties of the films made of the PUGM hybrid particles were investigated. It was observed that the modulus of the PU films increased upon the addition of PMMA particle because of a filler effect. In addition, it was seen that the modulus of PUGM hybrid films increased further with increasing the number of covalent bonds. This was attributed to “restricted mobility” of PU chains anchored to the PMMA particles. It was also observed that the tensile strength changed only slightly for PUGM particles, suggesting that the PU matrix was probably responsible for the necking behavior of the films. The elongation of the samples was found to depend on both the presence of covalent bonds between the PMMA particles and PU matrix and the reduced mobility of the PU chains anchored to PMMA particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

14.
The waterborne polyurethane (PU) prepolymer was first prepared based on isophorone diisocyanate, polyether polyol (NJ‐210), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate via in situ method. The crosslinked waterborne polyurethane‐acrylate (PUA) dispersions were prepared with the different functional crosslinkers. The chemical structures, optical transparency, and thermal properties of PU and PUA were confirmed by Fourier transform infrared spectrometry, ultraviolet–visible spectrophotometry, and differential scanning calorimetry. Some physical properties of the aqueous dispersions such as viscosity, particle size, and surface tension were measured. Some mechanical performances and solvent resistance of PUA films were systemically investigated. The experimental results showed that the particle sizes of the crosslinked PUA aqueous dispersions were larger than the PU and increased from 57.3 to 254.4 nm. When the ratios of BA/St, BA/TPGDA, and BA/TMPTA were 70/30, PUA films exhibited excellent comprehensive mechanical properties. The tensile strength and elongation at break of the film were 2.17 MPa and 197.19%. When the ratio of BA/St was 30/70, the film had excellent water resistance and was only 6.47%. The obtained PUA composites have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings, and wood finishes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

15.
In the present study, nanostructured zinc oxide (ZnO) films have been successfully synthesized using fruit extract of Viburnum opulus L. (VO) on glass slides by successive ionic layer adsorption and reaction (SILAR) procedure. The impact of VO concentrations on the structural, morphological, optical, electrical, and antibacterial attributes of ZnO films has been investigated in detail. The samples' XRD patterns present a hexagonal crystal structure with a preferential orientation along the (002) plane. The crystallite size values of ZnO samples were found to be in the ranges from 14.88 to 9.23 nm. The supplementation of VO to the synthesis solution remarkably affected the surface morphological features of the ZnO films. The optical results demonstrated that band gap energy values of the ZnO films at room temperature were decreased from 3.20 to 3.07 eV as a function of VO content in the bath solution. The films' electrical properties were determined by impedance analysis in the frequency range of 20 Hz ?1 MHz. Impedance-frequency measurements showed VO insertion to ZnO thin films cause an increase in impedance value at the low frequencies. Cole-Cole plots with a single semi-circle confirmed the contribution of grain and grain boundary for the electrical conduction process. The agar disk diffusion method was used to test the antibacterial properties of ZnO/VO inserted ZnO and inhibition zones were measured. VO inserted ZnO showed a stronger inhibitory effect on gram-positive bacteria Staphylococcus aureus (ATCC 25923) and gram-negative bacteria Escherichia coli (ATCC 35218) than ampicillin antibiotic used as a control group. In line with the promising bactericidal results of a new generation, VO inserted ZnO, the nanostructured product with this study, it can also be applied in multidrug-resistant clinical isolates obtained from patients.  相似文献   

16.
采用溶剂铸膜法制备了聚己二酸/对苯二甲酸丁二酯(PBAT)/聚乳酸(PLA)/对苯二甲酸二辛酯(DOTP)/氧化锌(ZnO)复合膜材料,并通过硬脂酸改性纳米ZnO,探讨了不同粒径ZnO以及改性纳米ZnO对复合薄膜力学性能、热性能、疏水性能、耐抽出性能以及抗菌性能的影响。结果表明,通过硬脂酸代替纳米ZnO表面的羟基极性基团,复合膜的耐抽出性能提高。硬脂酸的长链烷基与高分子链的链纠缠改善了改性纳米ZnO与PBAT的相容性。随着ZnO粒径的减小以及改性纳米ZnO含量的增大,复合薄膜的热性能有所下降,但耐抽出性能提高。拉伸强度提高,最高达到13.8 MPa。复合膜的疏水性能得到改善,接触角最高达到110°,复合膜材料的抑菌区域增大,抗菌性能有所增强。  相似文献   

17.
《Ceramics International》2020,46(15):24120-24128
Zinc oxide (ZnO) is one of the most prospective material for optoelectronic, piezoelectric, spintronic and gas sensing applications. Doping rare-earth elements in ZnO leads to significant enhancement in its electrical properties. Herein, pure and Tb-doped ZnO nanoparticles were synthesized via chemical co-precipitation method and their structural, morphological and electrical properties were systematically studied. As a result of Tb-doping, hexagonal shaped ZnO nanorods converted to taper-like nanoparticles. Tb–ZnO nanoparticles exhibited high Curie temperature (Tc ~ 225 °C) and enhanced dielectric properties as compared to pure ZnO nanoparticles. Electrical conduction studies revealed a significant reduction in the leakage current as a result of Tb-doping. Piezoelectric nanogenerators based on synthesized nanoparticles were fabricated and piezoelectric output voltage of the Tb-doped ZnO based nanogenerator was measured to be remarkably enhanced (by up to ~ 4 times) compared to pure ZnO based nanogenerator. These results indicate Tb–ZnO:PDMS composite films on flexible substrates could be promising candidate for energy harvesting application.  相似文献   

18.
A series of polyurethane acrylate (PUA)/ZnO nanocomposite films with different ZnO contents were prepared via a UV-curing system. To ensure good dispersion in the PUA matrix, ZnO nanoparticles were modified with a silane coupling agent and confirmed by FT-IR analysis. The morphological structures, thermal properties, mechanical properties and water transfer properties of the prepared films were investigated as a function of their ZnO concentration. WAXD and SEM analyses showed that the surface-modified ZnO nanoparticles were homogeneously dispersed in the PUA matrix and the molecular ordering increased with increasing ZnO content. Compared with neat PUA, the hardness and elastic modulus in films increased from 0.03 to 0.056 GPa and from 2.75 to 3.55 GPa, respectively. Additionally, the water uptake and WVTR in the PUA/ZnO nanocomposite films decreased as the ZnO content nanoparticles increased, which may come from enhanced molecular ordering and hydrophobicity in films. UV light below approximately 450 nm can be efficiently absorbed by incorporating ZnO nanoparticles into a PUA matrix, indicating that these composite films exhibit good weather ability and UV-shielding effects. The enhanced physical properties achieved by incorporating modified ZnO nanoparticles can be advantageous in various applications, whereas the thermal stability of the composite films should be increased.  相似文献   

19.
《Ceramics International》2023,49(12):20218-20233
We report facile biosynthesis of Ag–ZnO nanohybrids consisting of Ag nanoparticles decorated ZnO nanobullets prepared by decorating wet chemically synthesized ZnO nanobullets with Ag nanoparticles through bioreduction of Ag + ions with aqueous extract of Piper nigrum fruits. The prepared nanomaterials were well characterized by FESEM, TEM, HRTEM, EDX, XRD, XPS, PL and UV–vis spectroscopy. FESEM and TEM analyses on the nanohybrids revealed ∼18 nm Ag nanoparticles decorating ZnO nanobullets with average size ∼48 nm. XRD results revealed hexagonal wurtzite ZnO with 22.4 nm crystallite size and FCC Ag with 18.7 nm crystalline size. Ag–ZnO nanohybrids exhibited strong antibacterial action against Escherichia coli, Bacillus oceanisediminis and Pseudomonas entomophila and efficiently inhibited their growth at 100 μg/mL, 50 μg/mL and 125 μg/mL, respectively. The molecular basis of antibacterial action of Ag–ZnO nanohybrids against E. coli was investigated using different biochemical and molecular assays. Addition of antioxidant histidine suppressed the antibacterial action of Ag–ZnO nanohybrids towards E. coli due to its ROS scavenging action. Bradford assay results showed enhanced protein leakage from Ag–ZnO nanohybrids treated E. coli, while TBARS assay results confirmed lipid peroxidation triggered by ROS. SEM on Ag–ZnO nanohybrids treated E. coli confirmed significant damage to the cell wall leading to morphology change. The antibacterial activity of Ag–ZnO nanohybrids against E. coli is mainly due to the ROS-induced oxidative stress, which caused enhanced lipid peroxidation, cell wall damage leading to significant protein leakage and DNA fragmentation.  相似文献   

20.
《Ceramics International》2016,42(8):9673-9685
ZnO thin films were prepared by sol–gel dip coating method onto glass substrates. The effects of aging time of the starting solution (2, 10 and 30 days) and the number of coats (2, 5 and 10 coatings) on structural, morphological and optical properties were investigated. Photocatalytic efficiency was also assessed. X-ray diffraction analysis indicates that all the films exhibit a Zincite-type structure with a preferred grains orientation along the [002] direction. The preferred orientation factor (POF) increases with aging time while the crystallite size decreases. The field emission scanning electron microscopy observations reveals nanorods morphology. The length of ZnO nanorods increase with increasing number of layers whereas their length decreases as a function of aging time while adopting a random orientation. A high optical transparency is observed for all ZnO thin films, ranging from 90 up to 96%. Methylene Blue (MB) dye photocatalytic degradation was found increases with aging time, reaching almost 94% after 10 h under UV irradiation. The apparent reaction rate (Kapp) obtained by Langmuir-Hinshelwood model increases with increasing aging time from, from 0.218 h−1 for 2 days to reach a steady state around 0.270 h−1. Nevertheless, a small variation of Kapp was recorded when varying the number of coats; 0.223–0.226 h−1.  相似文献   

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