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1.
A silver–polycarbonate (Ag–PC) matrix was prepared by a γ‐radiation‐assisted diffusion method, and its antibacterial properties were studied. Rutherford backscattering spectroscopy, X‐ray diffraction, and transmission electron microscopy results showed the diffusion of good, crystalline‐structured (face‐centered cubic) silver nanoparticles (AgNPs) inside polycarbonate (PC) after irradiation. Ultraviolet–visible spectroscopic results indicated a blueshift in the surface plasmon resonance of the AgNPs; this revealed a particle size decrease with increasing γ‐radiation dose. This was also supported by the scanning electron microscopy results. The microstructure of the pristine PC and silver‐doped PC was monitored with positron annihilation spectroscopy, and it showed decreases in the free‐volume hole size and fractional free‐volume for Ag–PC and γ‐ray‐irradiated PC. This corroborated the Doppler broadening spectroscopy results. The thermal degradation temperature of PC was increased because of the diffusion of AgNPs in PC. The antibacterial activity of the synthesized Ag–PC matrix was evaluated by the zone of inhibition, and the results demonstrated its bacterial growth inhibition ability. The results indicate the potential to produce an Ag–PC matrix for various applications in medical and food industries. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43729.  相似文献   

2.
Stimuli‐sensitive polymers are a type of smart polymers having the capability to change their configuration or properties under adequate stimuli as heat, pH, magnetic field, mechanical strength, among other. The aim of this work was to synthesize nanostructured polymers with antibacterial properties capable to change their retention properties of divalent metal ions by external stimuli (pH and ionic strength). For that, a polymerizable nanostructured crosslinker (PNC) based on silver nanoparticles (AgNPs) and acrylic acid was synthesized. Later, NPSS was synthesized by free‐radical polymerization, characterized by different analytical techniques and its retention properties of divalent ions (Cu2+, Fe2+, Mn2+, and Zn2+) were studied at different pHs and ionic strengths (5.0, 7.0, and 9.0; and 0.0, 0.5, and 1.5% NaCl, respectively). It was evidenced that AgNPs can be synthesized using acrylic acid as stabilizing agent, and later, be used for synthesis of NPSS by free‐radical polymerization. For NPSS, metal ion retention decreases as pH is increased; in addition, results suggest that the electrostatic interaction is not the only determining factor in the retention of ions. Other possible factors which would be affecting the retention are: water flow by swelling capacity and water flow by osmotic stress resulting of high salt concentration. NPSS showed antimicrobial activity against Escherichia coli and Staphylococcus aureus which was enhanced by incorporation of PNC based on AgNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46001.  相似文献   

3.
A facile method for strongly anchoring silver nanoparticles (AgNPs) onto cotton fabrics was reported. It consists in loading AgNPs onto the cotton fiber preliminary coated with maleic anhydride plasma polymer layer. This results in hydrolyzis and ring opening of anhydride groups followed by electrovalent bonding of silver ions and reduction in NaBH4. X‐ray photoelectron spectroscopy (XPS), infrared spectroscopy, and scanning electron microscope (SEM) were used to analyze changes in the surface chemical composition and morphology of the plasma modified fibers. The presence of AgNPs was confirmed by UV–Visible spectroscopy and atomic force microscopy (AFM) images. Remarkably, varying plasma duty cycle for plasma polymer deposition allowed tailoring the amount of loaded AgNPs. The highest amount of AgNPs was obtained with the lowest duty cycle values. Qualitative tests showed that silver containing plasma modified cotton displays significant antibacterial activity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41279.  相似文献   

4.
This article reports the temperature‐sensitive, green tea (GT)‐based silver‐nanocomposite hydrogels for bacterial growth inactivation. The temperature‐sensitive hydrogels were prepared via free‐radical polymerization using temperature‐sensitive N‐isopropylacrylamide (NIPAM) monomer with GT as the hydrogel matrix. The nanocomposite hydrogels were encapsulated with silver ions via swelling method, which was later reduced to silver nanoparticles using Azadirachta indica leaf extract. The temperature‐sensitive silver nanocomposite hydrogels were analyzed by using Fourier transforms infrared, UV–visible spectroscopy, differential scanning calorimetry–thermogravimetric analysis, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The prepared hydrogels exhibited higher phase volume transition temperature than the NIPAM. The inhibition zone study of the inactivation of bacteria on the developed hydrogels was carried out against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus), which revealed that the prepared hydrogels are helpful for the inactivation of these bacteria due to the high stabilization of antibacterial properties of the silver nanoparticles. The developed hydrogels are promising for biomedical applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45739.  相似文献   

5.
Polymeric microspheres have been demonstrated as a potentially useful vehicle for targeted delivery applications. In this work we report on the preparation of polymer microspheres capable of performing specific reaction chemistry. The microspheres are modified with silver nanoparticles in a two‐step reaction. The first step involves formation of the microsphere by UV‐induced polymerization of pyrrole and the second step is the reduction of silver cations to metallic silver in situ. The resulting Ag‐decorated microspheres were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X‐ray, and thermogravimetry analysis. The catalytic reaction behavior of the decorated microspheres was illustrated through the reduction reaction of m‐nitrobenzene sulfonate acid in the presence of sodium borohydride. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43653.  相似文献   

6.
[RuCl2(p‐cymene)]2 was reacted with silver triflate and thiophene to give the sandwich complex [Ru(η5‐C4H4S)(η6p‐cymene)](PF6)2, which was characterized with NMR spectroscopy (1H‐NMR, 13C‐NMR, and 31P‐NMR), Fourier transform infrared spectroscopy, elemental analysis, and cyclic voltammetry. The behavior of this new complex in dimethyl sulfoxide with regard to the amount of absorbed water was investigated by both NMR and cyclic voltammetry; the formation of other species that affected electropolymerization was demonstrated. However, under optimal working conditions (in an anhydrous medium), the complex was successfully immobilized on a platinum electrode via an electro‐oxidation pathway through the thiophene ligand. This generated a highly stable, electroactive polymer film. Its response to the doping–undoping (charge–discharge) and redox processes, added to its high stability, promises important applications for this novel material. Moreover, this opens up the possibility of testing other compounds, such as [Ru(η5‐thiophene)(η6‐arene)], that were previously synthesized and reported for their electropolymerization and use as sensors according to their redox properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43559.  相似文献   

7.
The objective of this work was to synthesize functional polymers, with boron removal properties, from high molecular weight linear polyols based on N‐methyl‐d ‐glucamine (NMDG) and polyurethane units as crosslinking reagent. For that, (4‐vinylbenzyl)‐N‐methyl‐d ‐glucamine monomer (VbNMDG) was synthesized from vinylbenzyl chloride and NMDG, and subsequently, high molecular weight linear poly(VbNMDG) was obtained by radical free polymerization. Later, polymer dots were obtained from poly(VbNMDG) and urethanization reactions using methylene diphenyl diisocyanate at room temperature. Monomers and polymers were characterized by different techniques (FTIR, DLS, elemental analysis, H1‐NMR). In addition, boron retention properties were studied by diafiltration technique using the azomethine‐H method. It was concluded that synthesis of polymer dots, with high boron retention capacity, can be easily synthesized by procedure described. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43895.  相似文献   

8.
The double‐hydrophobic well‐defined polydimethylsiloxane‐block‐poly(methyl methacrylate) (PDMS‐b‐PMMA) diblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Their chemical compositions and the structure were investigated. The micellization behavior of the double‐hydrophobic diblock copolymers with equal block length was thoroughly studied. The results showed that their self‐assembly behavior was analogous to the star‐like micelles. Furthermore, the effect of temperature on the aggregates was investigated to verify that the resulting copolymer (PDMS‐b‐PMMA) was to some extent temperature sensitive. Till date, there have been few reports on the utilization of nonamphiphilic block copolymers to synthesize and confine metal nanoparticles in aggregates. In this study, we explored the role of double‐hydrophobic block copolymers as a mediator for organically dispersible silver nanoparticles (AgNPs) and it offered to be an effective stabilizer for preparing AgNPs. Besides, AgNPs generated in organic solvent is an important addition to the hitherto predominantly water‐based processes for producing nanoparticles inside the polymer surfactant. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers  相似文献   

9.
Three‐dimensional polymeric networks, which quickly swell by imbibing a large amount of water or deswell in response to changes in their external environment, are called hydrogels. These types of polymeric materials are good potential candidates for drug‐delivery systems. In this study, we first synthesized poly(vinyl acetate‐co‐maleic anhydride) by free‐radical copolymerization. Then, they were modified with different molar ratios of melamine to prepare hydrogels that could be used in drug‐delivery systems. The hydrogels were characterized by Fourier transform infrared spectroscopy, 1H‐NMR, differential scanning calorimetry, and scanning electron microscopy. In the second step, Ceftazidime antibiotic was loaded on selected hydrogels. The in vitro drug release was investigated and compared in three different media (HCl solution at pH = 3 and buffer solutions at pH 6.1and pH 8). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40389.  相似文献   

10.
Polyacrylamide gels are widely used as matrices for biomolecular analysis and fractionation, and they are being developed as biomaterials for diverse medical and industrial applications. This study reports silver nitrate as a novel catalyst for the synthesis of polyacrylamide gels from acrylamide and N,N‐methylene bisacrylamide monomers. The conditions were defined for silver‐catalyzed, free‐radical‐induced polymerization, and a suitable buffer system was devised for the electrophoretic resolution of nucleic acids. A silver‐staining procedure was modified for these gels, and they were compared with N,N,N′,N′‐tetramethylethylenediamine‐catalyzed gels for sensitivity and gel background. Silver nitrate and ammonium persulfate at final concentrations of 100 and 625 μg/mL, respectively, polymerized the resolving gels within 20 min at room temperature. These gels exhibited antimicrobial properties. The gels with ≥10 μg/mL silver nitrate showed a zone of complete inhibition of Staphylococcus aureus growth on a Luria–Bertani agar plate. The silver‐catalyzed gels were also suitable as antigen‐ and drug‐delivery devices. Silver, acting as both a catalyst and a microbicidal agent, was better than N,N,N′,N′‐tetramethylethylenediamine for the synthesis of polyacrylamide gels as drug‐ and oxygen‐delivery devices for topical applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
Silver nanoparticles (AgNPs) were synthesized in reverse microemulsions using silver nitrate as silver source, hydrazine hydrate as reducing agent, n‐heptane as oil phase, cetyl trimethyl ammonium bromide (CTAB) as surfactant, and isoamyl alcohol as cosurfactant. A uniform silver nanoparticles/polystyrene (AgNPs/PS) composite was further prepared by a reverse microemulsion polymerization method. The morphologies and structures of the AgNPs and the AgNPs/PS composite were characterized by UV‐visible spectroscopy (UV–vis), X‐ray diffraction (XRD), fourier transform infrared spectra (FTIR), and transmission electron microscopy (TEM). Furthermore, the molecular weight of the AgNPs/PS composite was measured by gel permeation chromatography (GPC), and the thermal stability of the AgNPs/PS composite was determined by thermal gravimetric (TG) analysis. Results show that the AgNPs have a particle size of 3–10 nm, and are almost spherical, uniform, and monodisperse both in a AgNPs colloid and in the AgNPs/PS composite. There are no characteristic peaks of silver oxide in the synthetic AgNPs and AgNPs/PS composite. The AgNPs/PS composite has a better thermal stability and a higher molecular weight than virgin PS. POLYM. COMPOS., 35:1325–1329, 2014. © 2013 Society of Plastics Engineers  相似文献   

12.
Microbial reduction of silver ion (conc. 1 mM AgNO3) was performed by Alkaliphilus oremlandii strain ohILAs in an alkaline pH 10. The synthesized silver nanoparticle was stabilized by poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) biopolymer which was also synthesized by the microbial culture of Alkaliphilus oremlandii strain ohILAs at pH8. The particle size and shape of the silver nanoparticles was studied by dynamic light scattering and under a transmission electron microscope and it was found that the particle size of polymer stabilized colloidal silver was comparatively lower (22–43nm) than that for the unstabilized one (63–93 nm). The stabilization of nanoparticles in polymer dispersed medium after around 60 days was confirmed from analysis of UV‐visible spectroscopy and scanning electron microscopy. The crystalline peaks as recorded with X‐ray's diffraction were observed at 2θ values of 38° and 43°, indicating the fcc crystalline structure of the silver nanoparticle. The antimicrobial activity of silver nanoparticles on gram‐negative bacteria strain (Escherichia coli XL1B) and gram‐positive strain (Lysinibacillus fusiformis) showed better performance by the solution of polymer stabilized nanoparticle than that for the non polymer stabilized one. The reduction of nitro group in p‐nitrophenol to p‐aminophenol was observed from the analysis of UV‐Visible spectroscopy in which, the shifting of absorption peak at 400 to 295 nm and the simultaneous regeneration of light brown color (λmax 410 nm) of silver nanoparticles confirmed the catalytic activity of silver nanomaterials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41495.  相似文献   

13.
A nanocomposite reservoir‐type hydrogel dressing of poly vinyl alcohol (PVA) was fabricated by a freeze–thaw method and loaded with silver‐nanoparticle‐coated chitosan wafers (Ag–CHWs). The Ag–CHWs were synthesized by a sonication technique with silver nitrate (AgNO3) and chitosan powder. Scanning electron microscopy images showed silver nanoparticles (AgNPs) with a size range of 10 ± 4 nm on the surface of the chitosan wafers, and the antibacterial efficacy (minimum inhibitory concentration) of the Ag–CHWs was measured against Pseudomonas aeruginosa (32 µg/mL), Staphylococcus aureus, (30 µg/mL) and Escherichia coli (32 µg/mL). The antimicrobial PVA hydrogel showed an improved tensile strength (~0.28 MPa) and gel content (~92%) in comparison with the blank hydrogels. Full‐thickness‐excision wound studies of the nanocomposite dressing on Wistar rats revealed enhanced wound contraction, improved inflammation response, re‐epithelization rate, neoangiogenesis, and granulation tissue formation in comparison to the control group. A flexible, biocompatible, nanocomposite reservoir dressing not only established the chitosan as a stabilizer but also proved the efficacious and safe utility of AgNPs toward chronic wound management. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43472.  相似文献   

14.
A fluorescent polyimide (PI) was synthesized by using perylene tetracarboxylic dianhydride (PTCDAH) and a oxydianiline (ODA) in N‐methyl pyrrolidone (NMP) solvent at 160 °C for 5 h under nitrogen atmosphere. Similarly, the fluorescent PI nanocomposites were prepared in the presence of silver (Ag) and vanadium pentoxide (V2O5) nanoparticles under identical experimental conditions. The above synthesized PI and its nanocomposites were characterized by FTIR spectroscopy, UV‐visible spectroscopy, Fluorescence emission spectroscopy, DSC, TGA, SEM, and FESEM. The data are carefully analyzed and compared with the literature values. The catalytic activity of the fluorescent nanocomposite fiber was tested towards the reduction of p‐nitrophenol (NiP), Cr(VI) and Rhodamine6G (R6G) dye. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44633.  相似文献   

15.
A facile and green method is developed for the preparation of polyelectrolyte‐stabilized silver nanoparticles (AgNPs ) using dopamine as a reducing agent. The AgNPs were prepared in the presence of the polyelectrolyte poly[acrylamide‐co ‐(diallyldimethylammonium chloride)] (PADA ) and amine‐functionalized silane matrices. Interestingly, only amine‐functionalized silanes led to AgNPs in the presence of PADA , whereas silane without amine functionalization failed to produce them. The catalytic ability of the AgNPs was investigated by adopting a benchmark reaction, i.e. reduction of 4‐nitrophenol in the presence of sodium borohydride. It was found that PADA ‐Ag(0.1)‐TPDT (TPDT = N ‐[3‐(trimethoxysilyl)propyl]diethylenetriamine) showed better catalytic activity when compared to other silver concentrations of 0.05, 0.5 and 1 mmol L?1. Remarkably, a very high normalized rate constant, 20 374 s?1 g?1, was observed for PADA ‐Ag(0.1)‐TPDT . © 2016 Society of Chemical Industry  相似文献   

16.
Free‐radical polymerization of p‐cumyl phenyl methacrylate (CPMA) was performed in benzene using bezoyl peroxide as an initiator at 80°C. The effect of time on the molecular weight was studied. Functional copolymers of CPMA and glycidyl methacrylate (GMA) with different feed ratios were synthesized by free‐radical polymerization in methyl ethyl ketone at 70°C, and they were characterized by FTIR and 1H‐NMR spectroscopy. The molecular weights and polydispersity indexes of the polymers and copolymers were determined by gel permeation chromatography. The copolymer composition was determined by 1H‐NMR. The glass‐transition temperature of the polymer and the copolymers was determined by differential scanning calorimetry. The reactivity ratios of the monomers were determined by the Fineman–Ross and Kelen–Tudos methods. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 336–347, 2005  相似文献   

17.
For the first time, synthesis and characterization of a nanostructured star‐shaped polythiophene (PTh) with tannic acid core by both chemical and electrochemical oxidation polymerization methods through a “core‐first” method is reported. The chemical structures of all samples as representatives were characterized by means of Fourier transform infrared (FTIR), and 1H nuclear magnetic resonance (NMR) spectroscopies. The electroactivity behaviors of the synthesized samples were verified under cyclic voltammetric conditions, and their conductivities were determined using the four‐probe technique. The synthesized star‐shaped PTh showed higher electrical conductivity and electroactivity than those of the PTh in both chemical and electrochemical polymerized samples, due to its large surface area, spherical, and three‐dimensional structure. Moreover, the thermal behaviors, optical properties, and morphologies of the synthesized samples were investigated by means of thermogravimetric analysis (TGA), ultraviolet–visible (UV–Vis) spectroscopy, and field emission scanning electron microscopy (FE‐SEM), respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43513.  相似文献   

18.
Nanocomposites based on high impact polystyrene (HIPS) and silver nanoparticles (AgNPs) were synthesized via in situ bulk‐suspension polymerization adding a colloidal suspension of AgNPs in styrene from the beginning of the reaction. The concentrations of AgNPs in the final nanocomposites were 0, 0.025, 0.10, and 1.0 wt%. The rate of polymerization and free radicals concentration were found to decrease with increasing AgNPs concentration. For nanocomposites with 0.025 and 0.10 wt% of AgNPs, the phenomenon of phase inversion (PI) during the mass polymerization occurred within the same range as that for the blank HIPS. Further, the impact strength of these nanocomposites did not present any changes as compared to the blank HIPS. However, there was no sign of the PI phenomenon in the case of 1.0 wt% of AgNPs, due to a decrease in the amount of free and graft polystyrene onto the rubber chain as the free radicals concentration diminishes with an increase in AgNPs. In this case the impact strength doubles the values of the blank HIPS due to the presence of a interpenetrated polymer network of crosslinked grafted rubber and polystyrene (PS) instead of the formation of a defined morphology. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers  相似文献   

19.
Chemically crosslinked hydrogels composed of carbohydrate‐based and thermoresponsive monomers, sucrose 1‐O′‐methacrylate (SMA), sucrose dimethacrylate, and N‐isopropylacrylamide, respectively, were synthesized by free radical polymerization. These materials were characterized with respect to their composition, thermoresponsiveness, porosity, degradability, and as drug and protein delivery systems. Swelling studies, thermomechanical analysis, and differential scanning calorimetry showed that the lower critical solution temperature behavior of the hydrogels can be controlled by the SMA amount in the copolymers. On the other hand, thermoporometry showed that the pore size is somewhat dependent on the composition, which is confirmed by scanning electron microscopy. Hydrolytic degradation studies indicated that SMA side chains, as well as the crosslinker (sucrose dimethacrylate), are hydrolysable at corporeal temperature and pH 10, and the water swelling capability of the resulting materials increases as the hydrolysis degree increases. Finally, protein delivery studies revealed that the kinetics of release can be tailored by the copolymer composition. The results of this study suggest the potential application of these hydrogels in drug delivery systems and tissue engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45495.  相似文献   

20.
Hydrogel silver nanocomposites have been used in applications with excellent antibacterial performance. Acrylic acid (AA)/itaconic acid (IA) hydrogels silver nanocomposites were prepared and applied as a coating on a textile substrate. Hydrogel matrices were synthesized first by the polymerization of an AA/IA aqueous (80/20 v/v) solution and mixed with 2‐2‐azobis(2‐methylpropionamide) diclorohydrate and N,N′‐methylene bisacrylamide until the hydrogel was formed. Silver nanoparticles were generated throughout the hydrogel networks with an in situ method via the incorporation of the silver ions and subsequent reduction with sodium borohydride. Cotton (C) and cotton/polyester (CP) textile fibers were then coated with these hydrogel silver nanocomposites. The influence of these nanocomposite hydrogels on the properties of the textile fiber were investigated by infrared spectroscopy (attenuated total reflectance), scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and antibacterial tests against Pseudomona aeruginosa and Staphylococcus aureus. The better conditions, in which no serious aggregation of the silver nanoparticles occurred, were determined. It was proven that the textiles coated with hydrogels containing nanosilver had an excellent antibacterial abilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2713–2721, 2013  相似文献   

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