Sonochemical deposition of silver nanoparticles on wool fibers

Silver nanoparticles were deposited on the surface of natural wool with the aid of powered ultrasound. The average particle size was 5–10 nm, but larger aggregates of 50–100 nm were also observed. The sonochemical irradiation of a slurry containing wool fibers, silver nitrate, and ammonia in an aqueous medium for 120 min under an argon atmosphere yielded a silver–wool nanocomposite. By varying the gas and reaction conditions, we could achieve control over the deposition of the metallic silver particles on the surface of the wool fibers. The resulting silver‐deposited wool samples were characterized with X‐ray diffraction, transmission electron microscopy, high‐resolution transmission electron microscopy, high‐resolution scanning electron microscopy, electron‐dispersive X‐ray analysis, Brunauer, Emmett, and Teller physical adsorption method, X‐ray photoelectron spectroscopy, and Raman and diffused reflection optical spectroscopy. The results showed that the strong adhesion of the silver to the wool was a result of the adsorption and interaction of silver with sulfur moieties related to the cysteine group. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1732–1737, 2007     

Immobilization of chitosan on nylon 6,6 and pet granules through hydrolysis pretreatment

Chitosan has been increasingly studied as an adsorbent for removing heavy metal ions and organic compounds from aqueous solutions. Most of the studies used chitosan in the form of flakes, powder, or hydrogel beads. This research investigates the immobilization of chitosan on other granular materials to overcome the poor mechanical property of chitosan and offers the potential for chitosan to be used as a regenerable adsorbent. Nylon 6,6 and poly(ethylene terephthalate) (PET) granules were partially hydrolyzed under an acidic or alkaline condition to allow chitosan to be coated or immobilized on the granules' surfaces. The surface morphologies of nylon 6,6 or PET granules before and after hydrolysis and those with immobilized chitosan layer were examined by scanning electron microscopy (SEM), and their surface properties were characterized through ζ‐potential analysis and X‐ray photoelectron spectroscopy. The immobilization of chitosan on nylon 6,6 or PET granules was identified to be through the formation of the salt structure (–NH…^?OOC–) between the surfaces of hydrolyzed nylon 6,6 or PET granules and the chitosan layer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3973–3979, 2003     

Preparation and properties of silver‐containing nylon 6 nanofibers formed by electrospinning

Nylon 6 nanofibers containing silver nanoparticles (nylon 6/silver) were successfully prepared by electrospinning. The structure and properties of the electrospun fibers were studied with the aid of scanning electron microscopy, transmission electron microscopy, energy‐dispersive spectroscopy, and X‐ray diffraction. The structural analysis indicated that the fibers electrospun at maximum conditions were straight and that silver nanoparticles were distributed in the fibers. Finally, the antibacterial activities of the nylon 6/silver nanofiber mats were investigated in a broth dilution test against Staphylococcus aureus (Gram‐positive) and Klebsiella pneumoniae (Gram‐negative) bacteria. It was revealed that nylon 6/silver possessed excellent antibacterial properties and an inhibitory effect on the growth of S. aureus and K. pneumoniae. On the contrary, nylon 6 fibers without silver nanoparticles did not show any such antibacterial activity. Therefore, electrospun nylon 6/silver nanocomposites could be used in water filters, wound dressings, or antiadhesion membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A convenient approach to synthesize stable silver nanoparticles and silver/polystyrene nanocomposite particles

In this study, silver nanoparticles were prepared by the reduction of silver nitrate in SDS+ isopentanol/styrene/H₂O reverse microemulsion system using sodium citrate as reducing agent. The Ag/PS nanocomposite particles were prepared by in situ emulsion polymerization of the styrene system containing silver nanoparticles that did not separate from the reaction solution. The polymerization dynamic characteristic was studied, at the same time, silver nanparticles and the encapsulation of composite particles were characterized by Fourier‐transform‐infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X‐ray diffraction (XRD) measurement, UV–vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The results of TEM and UV–vis absorption spectra showed that well‐dispersed silver nanoparticles have a narrow size distribution. XRD showed that Ag and Ag/PS nanocomposite particles were less than 10 and 20 nm in size, which is similar to those observed by TEM. The results of XPS spectra revealed that the microemulsion system can stabilize the silver nanoparticles from aggregation and provided supporting evidence for the polystyrene encapsulated silver nanoparticle structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

Simultaneous coloration and functional finishing of cotton fabric using Ag/ZnO nanocomposite

In this study, colored cotton fabric with special functions, including self‐cleaning, anti‐bacterial, and ultraviolet (UV) blocking were prepared by applying zinc oxide as a photocatalyst and using silver nanoparticles as both a novel class of colorant for coloration and an agent capable of modifying the zinc oxide nanoparticles. The homogenous distribution of Ag/ZnO nanocomposite on the fibre surface was confirmed by field emission scanning electron microscopy (FE‐SEM), Energy‐dispersive X‐ray spectroscopy (EDS) and X‐ray mapping. X‐ray diffraction patterns showed the presence of the nanocomposite on the treated cotton fabric. The results indicated that adding silver nanoparticles to zinc oxide led to better self‐cleaning properties, even the photocatalytic activity of ZnO had no negative effect on fabric colour. Moreover, this process imparted proper anti‐bacterial properties and UV‐blocking activity to cotton fabrics.     

A facile synthesis of a novel three‐phase nanocomposite: Single‐wall carbon nanotube/silver nanohybrid fibers embedded in sulfonated polyaniline

A three‐phase water‐soluble nanocomposite of single wall carbon nanotube/silver nanoparticle hybrid fibers embedded in sulfonated polyaniline has been synthesized by a simple chemical solution mixing process. The nanocomposite has been characterized by high resolution electron microscopy, X‐ray diffractometry, FTIR spectroscopy, Raman spectroscopy, and thermogravimetric analysis. Optical and electrical characteristics of the nanocomposite have been determined by UV–vis absorption spectroscopy, photoluminescence spectroscopy, and four‐probe electrical conductivity measurement. A surface plasmon absorption band obtained around 460 nm indicates the presence of silver nanoparticles in the composite. The optical band gap calculation for sulfonated polyaniline vis‐a‐vis the nanocomposite supported the conductivity measurement. Over 1300 times increase in DC electrical conductivity has been observed for the three‐phase nanocomposite, with a filler loading of 20 wt %, at 306 K. This observation could be explained by Mott's variable range hopping model considering a three‐dimensional conduction. Such a nanocomposite has immense potential for use as a cathode material in lithium‐ion batteries and supercapacitors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41692.     

Synthesis and characterization of nylon 1012/clay nanocomposite

A nylon 1012/clay nanocomposite was prepared by melt polycondensation polymerization of diamine and diacid in the presence of organoclay. The nylon 1012 and nanocomposite were characterized by Fourier transform IR spectroscopy with attenuated total reflection, and a shift of the Si? O? Si band toward a lower wavenumber was found as the result of the strong interaction of nylon 1012 with the organoclay. The X‐ray diffraction analysis and transmission electron microscopy observation showed that the clay minerals were exfoliated. Clay platelets increased the crystallization rate but decreased the crystallinity. Differential scanning calorimetry and dynamic mechanical thermal analysis measurements showed that the glass‐transition temperature of the nylon 1012/clay nanocomposite decreased to some degree as compared to nylon 1012 because of the combined effect of confinement and the reduction of the physical crosslink density. The mechanical properties of the nanocomposite such as the tensile strength and tensile modulus are higher than those of nylon 1012, and the water absorption is reduced because of the improvement in the barrier property of the nanocomposite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2403–2410, 2002     

Synthesis and application of polymer–clay nanocomposite‐supported dichromate oxidizing agent

A hybride polymer–clay nanocomposite supported dichromate reagents was prepared. Direct interaction of poly(styrene‐co‐N‐methyl‐4‐vinylpyridinium) iodide with sodium montmorillonite (MMT) through ion exchange between sodium cations in MMT and pyridinium ions in the copolymer afforded a polymer–clay nanocomposite (3). The resulting nanocomposite was reacted with potassium dichromate to form the nanocomposite‐supported reagents (4). The structure of the resulting nanocomposite was characterized by elemental analysis, infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. The dispersion of the MMT particles in the polymer matrix was confirmed using scanning electron microscopy. X‐ray mapping for silicon in the nanocomposite revealed uniform distribution of Si in the polymer matrix. The effectiveness of these materials has been tested for oxidation of saturated primary, secondary and benzylic alcohols to their corresponding aldehydic and ketonic compounds in addition to oxidation of quinol to the corresponding quinone. Importantly, there is almost no formation of side‐product of this process. POLYM. COMPOS., 36:2066–2075, 2015. © 2014 Society of Plastics Engineer     

Preparation of antibacterial temperature‐sensitive silver‐nanocomposite hydrogels from N‐isopropylacrylamide with green tea

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.     

The effect of organo‐montmorillonite on the compatibility and properties of nylon 66/polypropylene blend

Nylon 66/polypropylene (PP) blends containing maleated polypropylene and organo‐montmorillonite (OMMT) have been prepared by melt compounding using a well‐dispersed master‐batch of nylon 6/OMMT nanocomposite as the source of OMMT. The effects of OMMT platelets on the compatibility and properties of the blends have been investigated. The blend morphology has been observed by the use of field emission scanning electron microscopy, showing a sharp decrease in domain size. The dispersion and location of OMMT have been investigated by X‐ray diffraction and transmission electron microscopy. A high‐density occupation of OMMT at the interface (i.e. Nylon‐g‐PP interphase region) is revealed by Fourier transform infrared spectroscopy and thermogravimetric analysis of the extraction residue after the removal of nylon phase by formic acid. A significant gain in stiffness is realized with the use of OMMT while the toughness of the material is maintained. The possible mechanism of compatibilization also is discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Composite electrodes consisting of platinum particles and polyaniline nanowires as electrocatalysts for methanol oxidation

Polyaniline (PANI) with nanowire (PANI‐(NW)) network structure (mean diameter 10–20 nm) was successfully deposited on a stainless steel (SS) electrode by a galvanostatic process. Platinum particles were deposited into the PANI nanowire network structure to result the PANI(NW)‐Pt composite electrode. The PANI(NW)‐Pt electrode was used as electrocatalysts for the electrochemical oxidation of methanol. The PANI nanowires and PANI(NW)‐Pt nanocomposite were characterized by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and UV–vis absorption spectroscopy. Nanowire morphology with an average diameter of 10–20 nm could be seen from scanning electron micrograph. Small amount (70 mμm) of spherical Pt particles could be deposited into the PANI(NW). Catalytic activity for the oxidation of methanol was studied by using cyclic voltammetry (CV). For comparative purposes, bulk Pt (deposited Pt on SS) and PANI nanowires based electrodes were tested. The PANI(NW)‐Pt nanocomposite electrode exhibited excellent catalytic activity for the electrooxidation of methanol in comparison to bulk Pt electrodes, which reveals that the PANI(NW)‐Pt nanocomposite electrodeis more promising for application in electrocatalyst as a support material. POLYM. COMPOS., 28:650–656, 2007. © 2007 Society of Plastics Engineers     

Nylon 10 10–montmorillonite nanocomposite made by intercalating polymerization

Nylon 10 10–montmorillonite nanocomposite has been prepared successfully using intercalating polymerization. The nanocomposite was investigated by X‐ray diffraction (XRD), Fourier transform infrared (FTIR), Atom force microscopy (AFM), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Differential scanning calorimeter (DSC), and Dynamic mechanical analysis (DMA). The results show that there are uniformly dispersed silicate layers in the nylon 10 10 matrix. The resulting nanocomposites have higher onset decomposition temperature and dynamic storage moduli than those of pure nylon 10 10. In addition, it was found that montmorillonite plays an important role in heterophase nucleation of the crystallization of nylon 10 10 in composites. Mechanical testing shows that the tensile modulus of nanocomposites is superior to that of nylon 10 10, and the ultimate strain values of the nanocomposites remain at a level similar to nylon 10 10 if the content of montmorillonite is not more than 6 wt%.     

Mn‐Loaded Mesoporous Silica Nanocomposite: A Highly Efficient Humidity Sensor

We report a relative humidity sensor based on manganese‐nanoparticle‐loaded mesoporous silica SBA‐15 using a facile hydrothermal route. The as‐developed nanocomposite material (Mn/SBA‐15) possesses a high surface area and a high pore volume. The obtained samples were characterized by using low‐angle X‐ray Diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), N₂ adsorption–desorption, high‐resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and energy‐dispersive X‐ray (EDX) spectroscopy techniques. The Mn/SBA‐15 exhibited, improved humidity response and recovery time as compared to pure SBA‐15 in the 11%–92% RH range. Optimal results were obtained for the 5 wt% Mn‐loaded SBA‐15 sample, which displayed excellent linearity, low hysteresis, and high humidity response. A change in ~5 orders of magnitude in resistance was observed over 11%–92% RH range. The investigation of humidity sensing properties of Mn/SBA‐15 nanocomposite shows that this material has good prospects as humidity sensor.     

Chitosan–poly(aminopropyl/phenylsilsesquioxane) hybrid nanocomposite membranes for antibacterial and drug delivery applications

We fabricated hybrid (CSSQ) membranes from chitosan and poly(aminopropyl/phenylsilsesquioxane) (PAPSQ) blends via a sol–gel reaction and solution casting followed by crosslinking with glutaraldehyde. The CSSQ membranes were then used for loading of 5‐fluorouracil (5‐FU) as an anticancer drug as well as templates for the production of silver nanoparticles (AgNPs). The physicochemical properties of the CSSQ membranes were examined using UV‐visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis and scanning electron microscopy (SEM). SEM results showed the controllable formation of AgNPs around PAPSQ. CSSQ–Ag nanocomposite membranes exhibited good antibacterial activity towards both Escherichia coli and Bacillus subtilis, while the CSSQ membranes worked as good carriers for controlled release of 5‐FU as model drug. The results suggest that both CSSQ and CSSQ–Ag nanocomposite membranes can be potentially applied for biomedical applications such as controlled release carriers as well as antibacterial wound dressing materials. © 2014 Society of Chemical Industry     

Studies on nylon 6/clay nanocomposites by melt‐intercalation process

The preparation of nylon 6/clay nanocomposites by a melt‐intercalation process is proposed. X‐ray diffraction and DSC results show that the crystal structure and crystallization behaviors of the nanocomposites are different from those of nylon 6. Mechanical and thermal testing shows that the properties of the nanocomposites are superior to nylon 6 in terms of the heat‐distortion temperature, strength, and modulus without sacrificing their impact strength. This is due to the nanoscale effects and the strong interaction between the nylon 6 matrix and the clay interface, as revealed by X‐ray diffraction, transmission electron microscopy, and Molau testing. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1133–1138, 1999     

Layer‐by‐layer modification of porous polybenzoxazine with silver nanoparticles for enhanced CO2 storage

Polybenzoxazine (PBZ) xerogels have been synthesized via quasi solventless method and coated with silver nanoparticles using the layer‐by‐layer (LbL) deposition method. After coating, the samples were carbonized at 800 °C to obtain high surface area porous carbon materials to be used for CO₂ storage. Evidences of the successful LbL deposition of the coating was provided by ultraviolet–visible and attenuated total reflection–Fourier transform infrared spectroscopy and the silver nanoparticles top layer was confirmed by scanning electron microscopy–energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. Results showed that the samples coated with silver nanoparticles displayed an increased CO₂ capacity from 3.02 to 3.39 mmol g^?1 when compared with the plain carbon PBZ. The LbL method for the modification of the pore surface in porous PBZ is simple and allows the facile tuning of the inner PBZ pore's surface chemistry with metallic nanoparticles that could be enhanced CO₂ storage capacity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45097.     

Highly Efficient Room Temperature Synthesis of Silver‐Doped Zinc Oxide (ZnO:Ag) Nanoparticles: Structural,Optical, and Photocatalytic Properties

Synthesis of silver‐doped zinc oxide (ZnO:Ag) nanoparticles through precipitation method has been reported. The synthesis was conducted at room temperature and no subsequent thermal treatment was applied. ZnO nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), fourier transmission infrared spectroscopy (FTIR), and ultraviolet‐visible (UV–Vis) spectroscopy. Detailed crystallographic investigation was accomplished through Rietveld refinement. The effect of silver content on structural and optical properties of resultant ZnO nanoparticles has been reported. It was found that silver doping results in positional shifts for the XRD peaks and the absorption band edge of ZnO. These were attributed to the substitutional incorporation of Ag⁺ ions into Zn²⁺ sites within the ZnO crystal. In addition, higher silver incorporation resulted in smaller size for ZnO nanoparticles. The photocatalytic activity of the ZnO:Ag nanoparticles was also determined by methylene orange (MO) degradation studies and compared to that of undoped ZnO. Improved photocatalytic activity was obtained for ZnO:Ag nanoparticles. It has been shown that an optimum amount of silver dopant is required to obtain maximum photocatalytic activity.     

Synthesis and crystallization behavior of nylon 12 14. II: Chain‐folded lamellar crystals and crystalline transformation behavior of nylon 12 14

Chain‐folded lamellar crystals of nylon 12 14 have been grown from a dilute 1,4‐butanediol solution with the “self‐seeding” technique. The morphology and structure of nylon 12 14 lamellar crystals were studied by both transmission electron microscopy (TEM) and wide‐angle X‐ray diffraction (WAXD). Two kinds of electron diffraction patterns were detected when different areas were selected for diffraction, which indicates that the α crystal phase and the β crystal phase coexist for nylon 12 14 under the present crystallization conditions. The WAXD diffractograms of the crystal mats confirm the results obtained from electron diffraction (ED). In addition, the changes of the crystal structure as a function of temperature for melt‐crystallized and dilute solution‐crystallized nylon 12 14 were monitored by variable‐temperature WAXD and variable‐temperature infrared spectroscopy (IR). It was found that the melt‐crystallized sample undergoes a Brill transformation at 80°C–90°C, but no Brill temperature can be observed for the dilute solution‐crystallized nylon 12 14.     

Microwave irradiation synthesis and characterization of RGO‐AgNPs/polystyrene nanocomposites

Polystyrene and reduced graphene oxide/silver (PSTY/RGO/AgNPs) nanocomposites were prepared via an in situ bulk polymerization method using two different preparation techniques. In the first approach, a mixture of silver nitrate, hydrazine hydrate, and polystyrene containing graphene oxide (PSTY/GO) were reduced by microwave irradiation (MWI) to obtain R‐(PSTY‐GO)/AgNPs nanocomposites. In the second approach, a mixture of the (RGO/AgNPs) nanocomposite, which was produced via MWI, and STY monomers were polymerized using an in situ bulk polymerization method to obtain PSTY‐RGO/AgNPs nanocomposites. The two nanocomposites were compared and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, Differential scanning calorimetry, and thermogravimetric analysis. The results indicate that the nanocomposites obtained using the first approach, which involved MWI, exhibited a better morphology and dispersion with enhanced thermal stability compared to the nanocomposites prepared without MWI. POLYM. COMPOS., 35:2318–2323, 2014. © 2014 Society of Plastics Engineers     

Microwave‐assisted synthesis of silver nanoparticles on cotton fabric modified with 3‐aminopropyltrimethoxysilane

In this study, silver nanoparticles were synthesized on cotton fabric modified with 3‐aminopropyltrimethoxysilane (APTMS) using sodium citrate as a reducing/stabilizing agent by microwave‐assisted process. The presence of a highly oriented amino‐terminated self‐assembled monolayer and formation of APTMS was demonstrated by an X‐ray photoelectron spectroscopy (XPS) analysis. The silver‐coated cotton fabrics were examined by scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX). UV protection, antistatic, and hydrophobic properties were also evaluated. The results show that silver‐coated fabric modified with APTMS possesses excellent antistatic, UV protection with ultraviolet protection factor (UPF) of 396.5 and superhydrophobic properties with contact angle of 153.2°. APTMS pretreatment improves the adhesive strength between silver coatings and cotton fabric. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3862–3868, 2013