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1.
A novel wound dressing material was prepared by electrospinning poly(vinyl alcohol) (PVA)/AgNO3 aqueous solution into nonwoven webs and then treating the webs by heat or UV radiation. Through SEM, TEM, and XPS analyses, it was observed that the silver (Ag) nanoparticles were generated and existed in the near surface of the electrospun nanofibers. It was found that heat treatment as well as UV radiation reduced the Ag+++ ions in the electrospun PVA/AgNO3 fiber web into the Ag nanoparticles. Also the heat treatment improved the crystallinity of the electrospun PVA fiber web and so it made the web unsolved in moisture environment. Therefore, it was concluded that the only heat treated electrospun PVA/AgNO3 fiber web was a good material as wound dressings because it had structural stability in moisture environment as well as excellent antimicrobial ability and, quick and continuous release of the effectiveness. POLYM. ENG. SCI., 47:43–49, 2007. © 2006 Society of Plastics Engineers  相似文献   

2.
TiO2/graphene‐MWCNT nanocomposite was prepared using solvothermal reaction for the effective distribution of TiO2 nanoparticles on carbonaceous materials. TiO2/graphene‐MWCNT nanocomposite was immobilized in poly(vinyl alcohol) (PVA) matrix for a convenient recovery after wastewater purification. MWCNT was incorporated in a nanocomposite not only to prevent the restacking of graphene but also to increase the electron transfer from TiO2. The detailed characterization of the nanocomposite was performed using SEM, EDX, XRD, XPS, and FTIR. The photocatalytic performance of PVA/TiO2/graphene‐MWCNT nanocomposite was investigated by UV spectroscopy on the basis of degradation of organic pollutants. PVA/TiO2/graphene‐MWCNT nanocomposite showed improved photocatalytic decomposition of more than 70% of residual dye left in case of using PVA/TiO2/graphene nanocomposite due to the improved electron transfer and the higher adsorption of organic pollutants. PVA/TiO2/graphene‐MWCNT nanocomposite was suitable as a promising material for the recyclable photocatalytic wastewater purification system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40715.  相似文献   

3.
Currently, the rising environmental concerns caused by nonbiodegradable food packaging materials have promoted the research and development of biodegradable alternatives. Polyvinyl alcohol (PVA) was selected as the substrate, and zinc oxide nanoparticles (ZnONPs) and titanium dioxide nanoparticles (TiO2NPs) were blended and modified with PVA, respectively. Based on the electrostatic spinning technology to prepare fiber membranes with high strength and UV blocking properties for grapes preservation. The study indicated that the tensile strength of PVA fiber membranes increased by 243% and 209% when ZnONPs and TiO2NPs were added at 1%, respectively. Under UV radiation, the PVA/ZnO composite membranes exhibited superior UV absorption than the PVA/TiO2 composite membranes. After conducting TG tests, it was found that the addition of ZnONPs decreased the thermal stability of the fiber membranes, while TiO2NPs could improve the thermal stability. Both composite membranes could extend grapes' shelf life, but the PVA/ZnO composite membranes were more effective at maintaining freshness than the PVA/TiO2 composite membranes.  相似文献   

4.
In this study the possibility of tailoring the textile nanocomposite materials based on the polyester fabric and TiO2 nanoparticles that can simultaneously provide desirable level of antibacterial activity, UV protection, and self‐cleaning effects with long‐term durability was investigated. To enhance the binding efficiency of colloidal TiO2 nanoparticles, the surface of polyester fabrics was activated by low‐pressure RF air plasma, and corona discharge at atmospheric pressure. Obtained functionalized textile materials provided maximum antibacterial efficiency against gram‐negative bacterium E. coli. High values of UV protection factor (UPF) indicate the maximum UV blocking efficiency (50+) of these fabrics. The results of self‐cleaning test with blueberry juice stains and photodegradation of methylene blue in aqueous solution confirmed excellent photocatalytic activity of TiO2 nanoparticles deposited on the fiber surface. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers  相似文献   

5.
In the present study, fumed silica (SiO2) nanoparticle reinforced poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) blend nanocomposite films were prepared via a simple solution‐blending technique. Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to elucidate the successful incorporation of SiO2 nanoparticles in the PVA/PVP blend matrix. A thermogravimetric analyzer was used to evaluate the thermal stability of the nanocomposites. The dielectric properties such as dielectric constant (?) and dielectric loss (tan δ) of the PVA/PVP/SiO2 nanocomposite films were evaluated in the broadband frequency range of 10?2 Hz to 20 MHz and for temperatures in the range 40–150 °C. The FTIR and UV–vis spectroscopy results implied the presence of hydrogen bonding interaction between SiO2 and the PVA/PVP blend matrix. The XRD and SEM results revealed that SiO2 nanoparticles were uniformly dispersed in the PVA/PVP blend matrix. The dielectric property analysis revealed that the dielectric constant values of the nanocomposites are higher than those of PVA/PVP blends. The maximum dielectric constant and the dielectric loss were 125 (10?2 Hz, 150 °C) and 1.1 (10?2 Hz, 70 °C), respectively, for PVA/PVP/SiO2 nanocomposites with 25 wt % SiO2 content. These results enable the preparation of dielectric nanocomposites using a facile solution‐casting method that exhibit the desirable dielectric performance for flexible organic electronics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44427.  相似文献   

6.
Polymeric materials, such as polyvinyl alcohol (PVA) and ethylene–PVA copolymers (EVOH) are widely used in the food sector as packaging materials because of their excellent properties. TiO2 nanoparticles (NPs) show photocatalytic activity; when added to the aforementioned polymers, on the one hand, they are expected to provide bactericidal capacity, whereas on the other hand, they could favor nanocomposite degradation. These types of nanoparticles can be derivatized with cyclodextrin macromolecules (CDs), which can act as food preservative carriers, increasing the packaging food protective properties. In this work, films containing β-Cyclodextrin (βCD)-grafted TiO2 nanoparticles and PVA or EVOH were prepared. Regarding the photocatalytic activity of the nanoparticles and the possible environmental protection, accelerated aging tests for PVA, EVOH, and their composites with cyclodextrin-grafted TiO2 nanoparticle (NP) films were performed by two methods, namely, stability chamber experiments at different conditions of temperature and relative humidity and UV light irradiation at different intensities. After analyzing the systems color changes (CIELAB) and Fourier transform infrared spectroscopy (FTIR) spectra, it was observed that the film degradation became more evident when increasing the temperature (25–80 °C) and relative humidity percentage (28–80%). There was no significant influence of the presence of CDs during the degradation process. When irradiating the films with UV light, the largest color variation was observed in the nanocomposite films, as expected. Moreover, the color change was more relevant with increasing NP percentages (1–5%) due to the high photocatalytic activity of TiO2. In addition, films were characterized by FTIR spectroscopy and variation in the signal intensities was observed, suggesting the increase of the material degradation in the presence of TiO2 NPs.  相似文献   

7.
A novel TiO2 thin film was prepared on the ceramic hollow fiber by the sol-gel method using poly(vinylpyrrolidone) (PVP) and polyvinyl alcohol (PVA) as additives. SEM images verified the formation of TiO2 layer with various thickness using different composition of titania sols. The effect of the PVP and PVA contents on the TiO2 sol properties, the separation and the antifouling performance of the ultrafiltration membranes were investigated thoroughly. When the contents of PVP and PVA were 1.0 wt% and 0.8 wt%, respectively, the resultant membrane showed a thickness of 0.55 μm with a pure water flux of 255 L m?2 h?1. In addition, the adherent foulant bovine serum albumin was applied to evaluate the antifouling performance. During the three fouling-recovery cycles, the flux recovery ratio and the flux decay ratio maintained about 99% and 30%. The BSA flux and rejection were still 169 L m?2 h?1 and 96.9% after the cycles, indicating a superior antifouling property.  相似文献   

8.
To examine the feasibility of developing flame‐retardant‐textile coated fabric systems with electrospun polyamide/boric acid nanocomposites, fiber webs coated on cotton substrates were developed to impart‐fire retardant properties. The morphology of the polyamide/boric acid nanocomposite fibers was examined with scanning electron microscopy. The flame‐retardant properties of coated fabric systems with different nanoparticle contents were assessed. The flame retardancy of the boric acid coated fabric systems was evaluated quantitatively with a flammability test apparatus fabricated on the basis of Consumer Product Safety Commission 16 Code of Federal Regulations part 1610 standard and also by thermogravimetric analysis. The 0.05 wt % boric acid nanocomposite fiber web coated on pure cotton fabric exhibited an increment in flame‐spreading time of greater than 80%, and this indicated excellent fire protection. Also, the coated fabric systems with 0.05% boric acid nanocomposite fiber webs exhibited a distinct shift in the peak value in the thermal degradation profile and a 75% increase in char formation in the thermooxidative degradation profile, as indicated by the results of thermogravimetric analysis. The results show the feasibility of successfully imparting flame‐retardant properties to cotton fabrics through the electrospinning of the polymer material with boric acid nanoparticles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

9.
In the present investigation, at first, the surface of titanium dioxide (TiO2) nanoparticles was modified with γ-aminopropyltriethoxy silane as a coupling agent. Then a new kind of poly(vinyl alcohol)/titanium dioxide (PVA/TiO2) nanocomposites coating with different modified TiO2 loading were prepared under ultrasonic irradiation process. Finally, these nanocomposites coating were used for fabrication of PVA/TiO2 films via solution casting method. The resulting nanocomposites were fully characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), thermogravimetric analysis/derivative thermal gravimetric (TGA/DTG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TEM and SEM results indicated that the surface modified nanoparticles were dispersed homogeneously in PVA matrix on nanoscale and based on obtained results a possible mechanism was proposed for ultrasonic induced nanocomposite fabrication. TGA confirmed that the heat stability of the nanocomposite was improved. UV–vis spectroscopy was employed to evaluate the absorbance and transmittance behavior of the PVA/TiO2 nanocomposite films in the wavelength range of 200–800 nm. The results showed that this type of films could be used as a coating to shield against UV light.  相似文献   

10.
Application of brown titanium dioxide (TiO2-x) and its modified composite forms in the photocatalytic decomposition of organic pollutants in the environment is a promising way to provide solutions for environmental redemption. Herein, we report the synthesis of effective and stable TiO2-x nanoparticles with g-C3N4, RGO, and multiwalled carbon nanotubes (CNTs) using a simple hydrothermal method. Among all the as-synthesized samples, excellent photocatalytic degradation activity was observed for RGO-TiO2-x nanocomposite with high rate constants of 0.075 min?1, 0.083 min?1 and 0.093 min?1 for methylene blue, rhodamine-B, and rosebengal dyes under UV–Visible light irradiation, respectively. The altered bandgap (1.8 eV) and the large surface area of RGO-TiO2-x nanocomposite impacts on both absorption of visible light and efficiency of photogenerated charge electron (e?)/hole (h+) pair separation. This resulted in enhanced photocatalytic property of carbon-based TiO2-x nanocomposites. A systematic study on the influence of different carbon nanostructures on the photocatalytic activity of brown TiO2-x is carried out.  相似文献   

11.
The goal of this project is to obtain poly(vinyl alcohol) (PVA)/TiO2‐bovine serum albumin (BSA) nanocomposite (NC) films in different weight percentages of modified TiO2. For this purpose, to prevent the accumulation of nanoparticles (NPs) in the PVA matrix, the surface of the TiO2 NPs was treated with the BSA molecules. To achieve this aim, ultrasonic waves were used as an environmentally friendly and green process that decrease the time of reactions, help better spreading of TiO2 NPs and maintain dimensions of TiO2 NPs in the nanoscale range. In the end, the features of the PVA/TiO2‐BSA NC films were considered with a variety of techniques. The Fourier transform infrared spectroscopy, energy dispersive X‐ray, and X‐ray diffraction showed that the BSA was well placed on the surface of TiO2 NPs. The thermal gravimetric analysis and UV‐visible results demonstrated that all the PVA/TiO2‐BSA NC films have better thermal and optical properties than the pure PVA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46558.  相似文献   

12.
Mesoporous anatase TiO2-pillared titanate has been successfully prepared by the exfoliation-restacking route. The resulting nanocomposite was characterized by powder X-ray diffraction, scanning electron microscope, thermogravimetric analysis, IR and UV–Vis spectroscopy, specific surface area and porosity measurements. It was revealed that the present nanocomposite exhibits greatly expanded specific surface area (~200 m2 g−1) with 2.8- and 6.6-nm-in-diameter mesopore structure, and that there exists an electronic coupling between the host titanate sheets and the guest anatase TiO2 nanoparticles in the pillared system. The results of degradation of methylene blue under ultraviolet and visible radiation show that the present nanocomposite exhibits much higher photocatalytic activities than that of TiO2 nanoparticles or layered titanate alone, which are based on the bandgap excitation and the dye sensitization.  相似文献   

13.
An interpenetrating polymer network (IPN) based on the sodium alginate (A) and partially neutralized poly(methacrylic acid) (MAA) was prepared by free radical polymerization followed by additional cross‐linking of sodium alginate with calcium ions. Obtained material (A/MAA IPN) was characterized by FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy, and rheological measurements. Swelling behavior of synthetized IPN has been also investigated. TiO2 nanoparticles (TiO2 NPs) were immobilized onto A/MAA IPN by dip‐coating method and obtained TiO2/IPN nanocomposite was used for removal of the methylene blue (MB) from aqueous solution. The photodegradation (under illumination) and sorption (in the dark) processes for dye removal were monitored through decrease of dye concentration in the solution by UV/VIS spectrometer. The TiO2/IPN nanocomposite sorbed approximately 93% of the MB from a 10 mg L?1 MB solution in the dark, but no degradation occurred. Likewise, more than 93% of dye was removed after 8 h of illumination. However, after 24 h of illumination, the samples were discolored indicating that dye molecules were successfully degraded. Thus, the TiO2/IPN nanocomposite could be utilized in the photodegradation–sorption process for the abatement of pollutants in water. POLYM. ENG. SCI., 55:2511–2518, 2015. © 2015 Society of Plastics Engineers  相似文献   

14.
ABSTRACT

Novel tertiary nanocomposite films comprising of poly (vinyl alcohol) (PVA), poly (4-styrenesulfonic acid) (PSSA) and titanium dioxide (TiO2) nanoparticles (NPS) were prepared using simple solvent casting method. The structural, thermal, morphological, thermo-mechanical and electromagnetic interference (EMI) shielding properties of PVA/PSSA/TiO2 nanocomposite films were investigated. The EMI shielding effectiveness (SE) of PVA/PSSA/TiO2 nanocomposite films in the X and Ku band was found to be 12 dB and 13 dB respectively at 25 wt% TiO2 NPs loading. These results demonstrate the possible applications of PVA/PSSA/TiO2 nanocomposite films as low cost, lightweight and flexible material for EMI shielding.  相似文献   

15.
The objective of this paper is investigating the effect of different localizations of titanium dioxide (TiO2) and hexagonal boron nitride (hBN) nanoparticles in the poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends on the ultraviolet (UV) blocking, infrared reflection (NIR), and thermal conductivity of the nanocomposites for the fabrication of bionanocomposites with high performance. Transmission electron microscopy images demonstrated that the different mixing sequences induced different nanoparticle localization in the immiscible PCL/PLA blend. These different localizations yielded differences in the properties of the hybrid quaternary nanocomposite. When the nanoparticles had different localizations, TiO2 at the interface and hBN in the PCL phase, the thermal conductivity was 0.86 Wm−1 K−1, 100% of UV radiation (λ = 300 nm) was blocked and 74% of NIR radiation was reflected. This nanocomposite has a strong potential for application as a multifunctional biodegradable film for agriculture, capable of absorbing UV radiation, reflecting NIR radiation, and conducting thermal energy.  相似文献   

16.
Films of poly(vinyl alcohol)/cadmium sulphide (PVA/CdS) nanocomposite containing various concentrations of Cd2+ ions were prepared using gamma radiation at different doses from 50 up to 200 kGy. The UV/VIS spectra revealed that the CdS/PVA nanocomposites showed blue shift for the absorption peak as compared with bulk CdS. As the irradiation dose increased, a gradual red shift in the wavelength accompanying with broadening of the absorption peak was observed. The estimated optical band gap energies and the calculated CdS particle sizes of (PVA/CdS) showed correlation between their values and the variable parameters (irradiation dose and Cd+2:S?2 molar ratio). Transmission electron microscopy images showed that the CdS/PVA nanocomposites were dispersed as spherical CdS nanoparticles with homogeneity at either lower concentration of CdCl2 or irradiation dose. The nano‐rod structures of CdS was accompanied with small agglomeration at either higher CdCl2 concentration or irradiation dose. A cubic phase and mixture of cubic and hexagonal phases of the prepared CdS nanoparticles were formed at lower and higher CdCl2 concentrations, respectively. Fourier Transform Infrared spectra confirmed the coordination of CdS nanoparticles with the hydroxyl groups of PVA matrix. POLYM. ENG. SCI., 55:2583–2590, 2015. © 2015 Society of Plastics Engineers  相似文献   

17.
In this study, low‐density polyethylene (LDPE) nanocomposite films with two types of nanoparticles, TiO2 (3 wt %) and Closite 20A (3 and 5 wt %), were prepared using a melt blow extrusion as an industrial method and their properties such as mechanical properties, water vapor, oxygen and carbon dioxide gas barrier, and antimicrobial activity were tested. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were also performed to determine the degree of dispersion and exfoliation of nanoparticles. Mechanical test indicated that the reinforcement in the presence of the nanocomposites was more than that with their conventional counterparts, and the highest stiffness was achieved in a sample containing 5 wt % clay and 3 wt % TiO2. Exfoliation of silicate layers and a good dispersion of TiO2 nanoparticles in LDPE were achieved as confirmed by XRD and TEM. The gas barrier properties were improved after formation of the nanocomposites especially by insertion of 5 wt % of clay nanoparticles as a filler in the LDPE matrix. The photocatalytic effect of the nanocomposite film was carried out by antimicrobial evaluation against Pseudomonas spp. and Rhodotorula mucilaginosa and by ethylene removal test using 8 W ultraviolet (UV) lamps with a constant relative intensity of 1 mW cm?2. The greatest effects were recorded by combining UVA illumination and active film. It was also proven that the photocatalyst thin film with improved barrier properties prepared by extrusion could be used in horticultural product packaging applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41764.  相似文献   

18.
BACKGROUND: Traditional treatment systems failed to achieve efficient degradation of anthraquinone dye intermediates at high loading. Thus, an airlift internal loop reactor (AILR) in combination with the TiO2‐photocatalytic ozonation (TiO2/UV/O3) process was investigated for the degradaton of 1‐amino‐ 4‐bromoanthraquinone‐2‐ sulfonic acid (ABAS). RESULTS: The AILR using Sphingomonas xenophaga as inoculum and granular activated carbon (GAC) as biocarrier, could run steadily for 4 months at 1000 mg L?1 of the influent ABAS. The efficiencies of ABAS decolorization and chemical oxygen demand (COD) removal in AILR reached about 90% and 50% in 12 h, respectively. However, when the influent ABAS concentration was further increased, a yellow intermediate with maximum absorbance at 447 nm appeared in AILR, resulting in the decrease of the decolorization and COD removal efficiencies. Advanced treatment of AILR effluent indicated that TiO2/UV/O3 process more significantly improved the mineralization rate of ABAS bio‐decolorization products with over 90% TOC removal efficiency, compared with O3, TiO2/UV and UV/O3 processes. Furthermore, the release efficiencies of Br? and SO42? could reach 84.5% and 80.2% during TiO2/UV/O3 treatment, respectively, when 91.5% TOC removal was achieved in 2 h. CONCLUSION: The combination of AILR and TiO2/UV/O3 was an economic and efficient system for the treatment of ABAS wastewater. © 2012 Society of Chemical Industry  相似文献   

19.
TiO2 nanoparticles and their application in packaging systems have attracted a lot of attention because of its antimicrobial activity. In this work, effect of TiO2 nanoparticles on the antibacterial and physical properties of polyethylene (PE)-based film was investigated. Results indicated that the antibacterial activity of TiO2-incorporated PE films should be due to the killing effect property of TiO2 nanoparticles against microorganisms. The TiO2-incorporated PE film exhibited more effective antibacterial activity for Staphylococcus aureus. The antibacterial activity to inactivate Escherichia coli or S. aureus was improved by UV irradiation. The inhibition ratio of TiO2-incorporated PE films sample irradiated for 60 min by UV light was improved significantly, which were 89.3% for E. coli and 95.2% for S. aureus, respectively, compared to that of TiO2-PE film without UV irradiation. The analysis of physical properties revealed that TiO2 nanoparticles increased the tensile strength and elongation at break of PE-based film. The climate resistance of nano-TiO2 films is greatly enhanced, compared to that of the blank PE film. Water vapor transmission increased from 18.1 to 24.6 g/m2·24 h with the incorporation of TiO2 nanoparticles. Results revealed that PE based film incorporating with TiO2 nanoparticles have a good potential to be used as active food packaging system.  相似文献   

20.
This paper reports the development of a high-impact epoxy nanocomposite toughened by the combination of poly(acrylonitrile-co-butadiene-co-styrene) (ABS) as thermoplastic, clay as layered nanofiller, and nano-TiO2 as particulate nanofiller. Response surface methodology (RSM) was applied for optimization and modeling of the impact strength of epoxy/ABS/clay/TiO2 quaternary nanocomposite. A second-order mathematical model between the response (impact strength) and variables (ABS, clay and nano-TiO2 contents) was derived. Analysis of variance (ANOVA) showed a high coefficient of determination value (R 2 = 98%). Under optimum conditions, maximum impact strength of 29.2 KJ/m2 with 197% increase compared to neat epoxy was experimentally obtained. Also correlation between morphology and impact strength of the nanocomposite was investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). A dispersion of exfoliated clay platelets, TiO2 nanoparticles with low agglomeration and ABS nanoparticles was obtained as morphology of the nanocomposite. A new and more effective method for impact toughening of epoxy was introduced. This study clearly showed that the addition of the combination of layered and particulate nanofillers along with ABS as thermoplastic has a considerable enhancement effect on impact strength of epoxy.  相似文献   

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