Synthesis and characterization of acrylic fibers with antibacterial silver nanoparticles

The present investigation reports the novel synthesis of acrylic fibers containing Ag nanoparticles under ultrasound irradiation. The effect of temperature and power of ultrasound irradiation in growth of the Ag nanoparticles were studied. The physicochemical properties of the nanoparticles were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results show a decrease in the particles size as the power of ultrasound irradiation decreased. Particle sizes and morphology of nanoparticles depend on temperature. As a result, an increase in temperature led to increase of particle size. The textile containing nanoparticles were tested for their antibacterial efficacy against E. coli and S. aureus and were found to possess significant antibacterial activity.     

Simultaneous synthesis of nano ZnO and surface modification of polyester fabric

In this study, synthesis of zinc oxide nanoparticles was carried out along with the hydrolysis of polyester fabric using sodium hydroxide to increase the surface activity and enhance the nanoparticles adsorption. The polyester fabrics were treated with zinc acetate and sodium hydroxide at different bath conditions, ultrasound and stirrer, resulting in formation of ZnO nanospheres and ZnO nanorods. The presence of zinc oxide with different shapes on the surface of the polyester fabrics was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Also, the X-ray diffraction patterns established the composition of wurtzite structure of zinc oxide. The self-cleaning property of treated polyester fabrics was evaluated through discoloring dye stain under sunlight irradiation. The antibacterial activities of the samples against two common pathogenic bacteria including Escherichia coli and Staphylococcus aureus were also assessed. The results indicated that the photocatalytic and antibacterial activities of the ultrasound treated polyester fabrics were superior compared to the stirrer treated samples.     

Development of nanofibrous membranes with far-infrared radiation and their antimicrobial properties

This study investigated the incorporation of nanoscale germanium (Ge) and silicon dioxide (SiO₂) particles into poly(vinyl alcohol) (PVA) nanofibers with the aim of developing nanostructures with far-infrared radiation effects and antimicrobial properties for biomedical applications. Composite fibers containing Ge and SiO₂ were fabricated at various concentrations of Ge and/or SiO₂ using electrospinning and layered on polypropylene nonwoven. The morphological properties of the nanocomposite fibers were characterized using a field-emission scanning electron microscope and a transmission electron microscope. The far-infrared emissivity and emissive power of the nanocomposite fibers were examined in the wavelength range of 5-20 μm at 37 °C. The antibacterial properties were quantitatively assessed by measuring the bacterial reductions of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Multi-component composite fibers electrospun from 11 wt% PVA solutions containing 0.5 wt% Ge and 1 wt% SiO₂ nanoparticles exhibited a far-infrared emissivity of 0.891 and an emissive power of 3.44·102 W m^?2 with a web area density of 5.55 g m^?2. The same system exhibited a 99.9 % bacterial reduction against both Staphylococcus aureus and Escherichia coli, and showed a 34.8 % reduction of Klebsiella pneumoniae. These results demonstrate that PVA nanofibrous membranes containing Ge and SiO₂ have potential in medical and healthcare applications such as wound healing dressings, skin care masks, and medical textile products.     

Surface modification of cellulose fibers by layer-by-layer self-assembly of lignosulfonates and TiO2 nanoparticles: Effect on photocatalytic abilities and paper properties

Depositing of TiO₂ nanoparticles on cellulose fiber surface has potential technological applications in the field of photocatalysis. With this motivation, multilayers composed of lignosulfonates (LS) and TiO₂ nanoparticles were constructed on cellulose fiber surface via layer-by-layer (LBL) self-assembly technique. X-ray photoelectron spectroscopy (XPS), zeta potential measurement and atomic force microscopy (AFM) were used to characterize the LS/TiO₂ multilayers on cellulose fiber surface. Moreover, the photocatalytic activities of modified cellulose fibers (decomposition of methyl orange and antibacterial test) were investigated. The decomposition efficiency of methyl orange for a (LS/TiO₂)₅ multilayer modified cellulose fibers was 74.7 % under 5 h UV irradiation. Photocatalytic decomposition efficiency of methyl orange by LS/TiO₂ multilayer modified cellulose fibers under the same UV irradiation time increased linearly with the number of bilayers. Antibacterial tests results revealed that the cellulose fibers modified with LS/TiO₂ multilayers exhibited excellent antibacterial activity against E.coil. The degree of E.coil growth inhibition for a (LS/TiO₂)₅ multilayer modified cellulose fiber reached as high as 93 %. In addition, the effect of LS/TiO₂ multilayers on properties of handsheets made from modified cellulose fibers was also considered. The air permeability of the handsheet prepared from fibers modified with TiO₂/LS multilayers had 6.1–24.3 % higher compared with that of handsheet prepared from original fibers. The wetting properties measurement results demonstrated that the water contact angle of handsheet oscillated with the increasing number of layers depended on building block which was in the outermost layer.     

Functional Antibacterial Finishing of Woolen Fabrics Using Ultrasound Technology

The growing concern for the personal health and hygiene has created the necessity of acquiring wool fabric antibacterial activity. Silicon dioxide nanoparticles (SiO₂ NPs) have appropriate features to enhance the functional properties of wool fabrics, especially with polymer application. In this study efficient coating using polyethylene glycol (PEG₂₀₀₀) and SiO₂ NPs were used for imparting antibacterial properties to treated fabrics. All the treatments were carried out using both conventional and ultrasound techniques. The physical and chemical properties were evaluated using FTIR, XRD, and SEM. The result indicated that treated wool fabrics by PEG/SiO₂ NPs improved the dyeability and antibacterial of the fabrics and also enhanced its mechanical properties. Furthermore, it is believed that the ultrasound radiation causes homogeneous distribution of cross-links and polymerization throughout the wool surface. This offers considerable advantages compared to conventional treatment.     

A study of hybrid organic/inorganic hydrogel films based on in situ-generated TiO2 nanoparticles and methacrylated gelatin

Methacrylated gelatin films with in situ-generated TiO₂ nanoparticles containing varying weight percentages of gelatin (0 %, 0.5 %, 1 %, 2 % and 4 %) were successfully prepared as novel biomaterials. ¹H-NMR spectroscopy confirmed their methacrylation with a 79 % degree of substitution. TiO₂ nanoparticles were uniformly distributed in the films with the average particle size increasing from 85 to 130 nm in proportion to an increase in TiO₂ concentration from 0.5 to 4 wt%. The water absorption of various gelatin methacrylamide/TiO₂ films was in the range of 471–758 %, which was enough to prevent wound beds from exudates accumulation. And in vitro degradation test in PBS showed that the three-dimensional structure of all samples basically remained unchanged although more than or nearly half the mass of specimens decreased after 4 weeks’ degradation, and the pH levels of all sample solutions were maintained in an adequate range of 6.5–7.4 for cell and tissue growth during the whole process. The antibacterial activities of the films against E. coli and S. aureus were measured via a shake flask test and demonstrated good performance after the importation of TiO₂ nanoparticles. Cytotoxicity testing revealed that all films had no cytotoxicity and showed favorable adherence in the presence of L929 cells. The results suggest that hybrid hydrogel films hold potential for antibacterial wound dressing and tissue engineering scaffold applications.     

Synthesis of silver nanoparticles with sericin and functional finishing to cotton fabrics

This research presents a novel strategy to fabricate multi-functional cotton textiles. In this study, silver nanoparticles-sericin (Ag NPS-sericin) hybrid colloid has been prepared using sericin as reducing agent and dispersing agent. Cotton fabrics was oxidized selectively with sodium periodate (NaIO₄) to generate oxidized cotton fabrics, and which has then been finished using Ag NPS-sericin hybrid colloid prepared to obtain multi-functional cotton textiles. The finished cotton fabric not only possessed excellent antibacterial activity, but also it was modified functionally by sericin protein, which endowed antibacterial cotton fabrics relatively smooth surface and good wear ability. Fourier transform infrared spectrogram confirmed that sericin protein was grafted onto cellulose fibers. Ag NPs were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and X-ray powder diffraction (XRD). The results of SEM, X-ray photoelectron spectroscopy (XPS) and EDS confirmed that silver nanoparticles and sericin been loaded successfully on the surface of cotton fabrics. The antibacterial experiments showed bacterial reduction rates of S.aureus and E.coli were able to reach above 99 %. After washing 20 times, it showed still good antibacterial activity at over 95 % against S.aureus and E.coli.     

Effect of UV irradiation on cellulase degradation of cellulose acetate containing TiO<Subscript>2</Subscript>

Cellulose acetate (CA) films containing anatase type titanium dioxide (TiO₂) nanoparticles were prepared by solution casting. The film surface was modified by UV irradiation using a grid type UV irradiator. The UV irradiation caused slight increase in photodegradation of the CA films with TiO₂ compared to the CA film alone. However, CA films irrespective of TiO₂ content did not show a significant enzymatic degradation by a cellulase fromAspergillus niger without UV irradiation. Upon UV irradiation, the biodegradability remarkably improved even in the CA film without TiO₂. The irradiation of CA films decreased both the water contact angle and the degree of substitution (DS) implying the decrease in acetyl groups of the CA film surface due to the photo-scission of the acetyl group and photooxidation, resulting in more facile biodegradation of the surface film layer. The substantial enhancement in biodegradation of the UV irradiated CA film containing TiO₂ was attributed to the increased hydrophilicity, lowered DS and zeta potential due to the photoscission and the photooxidation effect of UV light. Also the increased surface area of the CA film due to the photocatalysis of TiO₂ particles may encourage the facile biodegradation.     

Effect of microwave irradiation on composition,structure and properties of rice (Oryza sativa L.) with different milling degrees

Effects of microwave irradiation on composition, structure, thermal and storage properties of rice with different milling degrees were investigated. Microwave irradiation partially inactivated the lipase and lipoxidase, damaged thiamine, and created puffed rice. In addition, the transition temperatures (T_o and T_P) of rice were shifted to higher temperatures, and the enthalpy of gelatinization decreased after irradiation. The effect was more obvious when the power of microwave was increased. Microstructure analysis showed that stress cracks and some “explosion” were created in rice kernels after microwave irradiation. Storage property analysis indicated that free fatty acid content of all rice samples increased gradually in the process of storage. Microwave irradiation reduced the release of free fatty acids during storage. The higher the power, the lesser the free fatty acids generated. The results suggested that microwave irradiation was potentially applicable for improving storage properties of brown and milled rice.     

Effect of Silver Particle size on color and Antibacterial properties of silk and cotton Fabrics

In this study silver nanoparticles with different particle sizes and hence colors were synthesized on silk and cotton fabrics through reduction of silver nitrate. Particle sizes of the silver colloids were measured by dynamic light scattering (DLS). The structure and properties of the treated fabrics were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV-Vis reflectance spectroscopy. Various characteristics of the treated fabrics including antibacterial activities against a Gram positive (Staphylococcus aureus) and a Gram negative (Escherichia coli) bacteria, color effect, wash and light fastness, water absorption, fabric rigidity, and UV blocking properties were also assessed. The results indicated that the treated fabrics displayed different colors in the presence of silver nanoparticles with different particle sizes and exhibited good and durable fastness properties. Also, the size of the silver particles had a tangible effect on antibacterial activity of treated fabrics and its antibacterial performance was improved by decreasing the size of particles. Moreover, this process imparted significantly UV blocking activity to fabric samples.     

Investigation on the Biodegradability and Antibacterial Properties of Nanohybrid Suture Based on Silver Incorporated PGA-PLGA Nanofibers

Polyglycolic acid-poly lactic glycolic acid (PGA-PLGA) electrospun nanofibers containing silver nanoparticles have been produced and twisted into the nanofibrous yarn. The morphology of nanofibers and produced yarns, as well as the mechanical properties of the yarns, were investigated. Furthermore, in vitro antibacterial properties and in vitro degradation behavior of yarns containing various silver nanoparticles were studied. SEM images confirmed that the addition of the silver nanoparticles into the polymer solution increases the fiber diameters. The result of the mechanical test of the yarns alone and used in two different forms of the knots was measured and results showed that the strength of the yarns without the knot was significantly more than that of others. The biodegradability test showed that the mechanical properties and the weight of the yarns were quickly reduced after subjecting to in vitro condition. The result of the antibacterial test indicated that the nanofiber yarns containing %3 silver nanoparticles were the most appropriate sample with a considerably antibacterial activity against both gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Escherichia Coli with inhibition zones of 8.1 and 9.5 mm, respectively; which demonstrated that silver nanoparticles retained their effectiveness after the electrospinning process. Therefore the nanofibrous yarns containing silver nanoparticles could be successfully produced by the electrospinning process with the proper antibacterial property as a candidate for the surgical sutures.     

Preparation of electroconductive,magnetic, antibacterial,and ultraviolet-blocking cotton fabric using reduced graphene oxide nanosheets and magnetite nanoparticles

The main goal of present study was the fabrication of cotton fabric with special functions, including electrical conductivity, magnetic, antibacterial, and ultraviolet (UV) blocking. In this regard, the cotton fabric was primarily coated with graphene oxide and then reduction of graphene oxide and synthesis of magnetite nanoparticles accomplished in one step. The alkaline hydrolysis of magnetite precursors and reduction of graphene oxide was simultaneously performed using sodium hydroxide to produce reduced graphene oxide/Fe₃O₄ nanocomposite on the fabric surface. The prepared cotton fabrics were characterized with field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The treated fabrics with reduced graphene oxide/Fe₃O₄ nanocomposite displayed a low electrical resistivity i.e. 80 kΩ/sq. Furthermore, the coated fabrics showed reasonable magnetic properties due to the presence of magnetite nanoparticles on the surface of cotton fabrics. Moreover, this process imparted proper antibacterial properties and UV blocking activity to cotton samples.     

The structure of wool fibers grafted with chitosan coated Ag-loading nano-SiO2 antibacterial composites

Wool fiber was grafted with chitosan coated Ag-loading nano-SiO₂ (CCTS-SLS) antibacterial composites under ultraviolet irradiation. The morphologies and structures of CCTS-SLS-wool were characterized by using scanning electronic microscopy, transmission electron microscopy, and Fourier transformation infrared spectrometry. The results show that a uniform and smooth antibacterial layer of 200 nm in thickness was formed on the surface of wool fiber by covalent bonding. The mechanical properties of the antibacterial wool fiber were improved. The antibacterial performance was found to be excellent, with antibacterial effect up to 90 % even after repeated washing. CCTS-SLS-wool possessed soft hand-feeling and good color.     

Antimicrobial properties of chitosan nanoparticles: Mode of action and factors affecting activity

The present investigation describes the synthesis and characterization of novel biodegradable nanoparticles based on chitosan for biomedical applications. The presence of primary amine groups in repeating units of chitosan grants it several properties like antibacterial activity, antitumor activity and so on. Chitosan forms nanoparticles spontaneously on the addition of polyanion tripolyphosphate which has greater antimicrobial activity than parent chitosan. In the present study, chitosan nanoparticles (ChNP) were prepared by the ionic gelation method. The physiochemical characteristics of nanoparticles were analyzed using XRD, SEM, FTIR. The antibacterial activity of chitosan nanoparticles against medical pathogens Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was evaluated by calculation of minimum inhibitory concentration (MIC) and compared with chitosan and chitin activity. The mode of action and factors affecting antibacterial activity were also analyzed. ChNP compounds exhibited superior antimicrobial activity against all microorganisms in comparison with chitosan and chitin. The antibiofilm activity was studied using crystal violet assay and growth on congo red agar. The study is thus a good demonstration of the applicability of chitosan nanoparticles as an effective antimicrobial agent with antibiofilm activity as well.     

Investigation of antibacterial properties of nano-ZnO assembled cotton fibers

Nano-ZnO assembled cotton fibers (NZCF) with excellent antibacterial properties were fabricated using microwave synthesis method. The effects of ZnO size, ZnO content, assembly times, microwave power and Zn²⁺ concentration of the synthesis solution on the antibacterial activity of the NZCF were studied using bacteriological tests such as Petri dish and agar diffusion method. The results show that NZCF has the antibacterial circle width (ACW) of about 1.5–2.3 mm and 2.3–3.4 mm against Escherichia coli (E. coli, gram-positive organism) and Staphylococcus aureus (S. aureus, gram-negative organism), respectively. It is also found that the antibacterial activity of NZCF increases with decreasing ZnO size, increasing ZnO content in NZCF and increasing Zn²⁺ concentration in synthesis solution.     

Reinforcement of wet milled jute nano/micro particles in polyvinyl alcohol films

Textile industry generate significant amount of waste fibres in form of short lengths during mechanical processing. However these short fibres possess excellent properties suitable for many other applications. The objective of this work was to use them for the preparation of nanoparticles/nanofibres as fillers in biodegradable composite applications such as food packaging, agriculture mulch films, automotive plastics, etc. The present paper concerns with jute fibres as a source of nanocellulose for reinforcement of PVA mulch films. Jute fibres were first refined to micro/nanoscale particles in form of nanofibrillar cellulose (NFC) by high energy planetary ball milling process in dry and wet condition. Wet milling was observed more efficient than dry milling in terms of unimodality of size distribution with reduction in size below 500 nm after milling for 3 hours. Later the obtained particles were used as fillers in Poly vinyl alcohol (PVA) films and their reinforcement evaluated based on thermal properties. It was observed that glass transition temperature (T_g) of PVA films improved from 84.36 °C to 95.22 °C after addition of 5 % jute particles without affecting % crystallinity and melting temperature (T _m) of PVA. Dynamic mechanical analysis of composite films with 5 % jute particles showed higher value of 14×10⁸ Pa for storage modulus in comparison to 9×10⁸ Pa of neat composite film. The percolation effect was observed more above glass transition temperature which consequently resulted in improved transfer of stiffness from jute particles to PVA matrix above 50 °C. The percolation phenomena also explained the improvement in thermal stability by 10 °C for every increased loading of jute particles due to formation of hydrogen bonds with PVA matrix.     

Immobilization of TiO2 nanoparticles on PET fabric modified with silane coupling agent by low temperature hydrothermal method

PET fabric was first modified with silane coupling agent KH-560, and then was loaded with a layer of nano-scaled TiO₂ particles using tetrabutyl titanate as precursor by low temperature hydrothermal method, followed by dyeing with Disperse Blue 56. The morphology, crystalline phase, chemical modification, thermal stability and optical property of PET fiber before and after treatments were studied by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, thermal gravimetric and diffuse reflectance spectrum techniques. The properties of tensile, air permeability, luster, ultraviolet (UV) protection, photocatalytic activity, K/S value and color fastness were also measured. It was found that compared with the TiO₂-coated fabric without modification with KH-560, the loading of TiO₂ nanoparticles on the surface of the TiO₂-coated fabric modified with KH-560 was obviously improved. The pure anatase TiO₂ nanoparticle was grafted onto the fiber surface. The onset decomposition temperature increased. The absorbing capability to ultraviolet radiation was enhanced. The properties of tensile, air permeability, luster, K/S value and color fastness changed slightly. The UV protection ability and photodegradation of methyl orange under UV illumination were enhanced to some extent.     

Antibacterial Coating of Glass Fiber Filters with Silver Nanoparticles (AgNPs) and Glycidyltrimethylammonium Chloride (GTAC)

Silver nanoparticles (AgNPs) were attached to glass fiber filters to improve their antibacterial properties using glycidyltrimethylammonium chloride (GTAC), a type of quaternary ammonium salt. The glass fiber filters treated with GTAC were placed into the Ag colloid and heat-treated at 43 °C for 90 min to attach AgNPs to the glass fiber filters. The glass fiber filters with the attached AgNPs were then analyzed by scanning electron microscopy and atomic force microscopy (AFM). The surface morphology of the glass fiber filters treated with GTAC and AgNPs was observed. The Ag atomic % of the glass fiber filters was analyzed according to the GTAC concentration, Ag colloid concentration, and AgNPs treatment temperature. The surface roughness of the glass fiber filters with the attached AgNPs was measured by AFM. The antibacterial tests of the GTAC and AgNP-treated glass fiber filters highlighted the sufficient antibacterial effects against E. coli, S. aureus, and P. aeruginosa. In particular, the antibacterial properties of glass fiber filters against S. aureus and P. aeruginosa were improved when the glass fiber filters were treated with both GTAC and AgNPs.     

Physicochemical characterization of hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem

In this paper, hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem aged six months were sequentially extracted with hot water, 2% KOH, and 5% NaOH. The water-soluble hemicelluloses H₁, and four alkali-soluble hemicellulosic fractions H₂, H₃, H₄ and H₅ were obtained, achieving a total yield of 59.60% based on the original hemicelluloses. Sugar composition analysis showed that the hemicelluloses were mainly composed of xylose (44.39-72.71%), arabinose (26.36-51.87%), ribose (0.93-2.72%), and uronic acid (0.29-5.27%). The structures of the hemicelluloses were determined to be mainly arabinoxylan, using the FT-IR and NMR techniques. The AFM images of fraction H₃ revealed a distribution of spherical nanoparticles with different sizes, while the fraction H₂ had helix rod and random coil feature. The SEM characterizations indicated that the fraction H₁ displayed spherical particles while the fraction H₃ had mainly flat particles at high magnification. Thermal stability was also analyzed using TG-DTG method and first-order kinetics model.     

Effect of CaCO3 contents on the properties of polyethylene nanocomposites sheets

Nanocomposites of high-density polyethylene/linear low-density polyethylene (HDPE/LLDPE) filled with untreated and surface treated nano-calcium carbonate (nCC) were prepared. The influence of isopropyl tri-(dioctylpyrophosphato) titanate (JN114) treatment of nCC on the morphology, mechanical, crystallization and flow properties of the nanocomposites were studied. The results of scanning electron microscopy (SEM) showed that JN114 treated nCC was better dispersion in the matrix than the untreated one. A fine dispersion of the treated nanoparticles in the nanocomposites was observed by transmission electron microscopy (TEM). The FTIR spectrum analysis revealed that the JN114 could change the surface properties of nCC, resulting in greater hydrophobicity of the surface and enhanced compatibility with nonpolar matrices. The tensile elastic modulus (E _c ) and Izod impact strength (SIC) of nanocomposites increased with the increasing of nCC content while tensile fracture strength (σ _b ) decreased. The JN114 treated nanocomposites had superior mechanical properties to those of the untreated ones. The compatibility of these nanocomposites was examined by DSC to estimate melting point (T _m ) and crystallization temperature (T _c ). Furthermore, the melt flow index (MFI) of the nanocomposite materials were measured. It was found that the MFI decreased with the addition of weight fraction of the nCC particles.