Preparation of nanocomposite fibers for permanent antibacterial effect

The polypropylene/silver nanocomposite fibers were prepared for the attainment of permanent antibacterial activity to common synthetic textile. The fibers were melt-spun by co-extrusion of polypropylene (PP) and PP/Ag master-batches using general conjugate spinning. Master-batches were made up of mixture of PP chips and nano-sized silver powder. The antibacterial efficacy of spun fibers was excellent not when the master-batch used as the core, but when used as the sheath. The antibacterial activity of nano-silver in fibers was evaluated after certain contact time and calculated by percent reduction of two kinds of bacteria; Staphylococus aureus and Klebsiela pneumoniae. For the characterization, differential scanning calorimetry (DSC) and wide-angle X-ray diffractometer (WAXD) were used for analysis of structure, thermal and crystallization behavior of the spun-fibers. Scanning electron microscopy (SEM) was carried out to observe particle distribution on the nanocomposite fibers.     

Antibacterial effect of nanosized silver colloidal solution on textile fabrics

This paper deals with the antibacterial efficacy of nanosized silver colloidal solution on the cellulosic and synthetic fabrics. Two kinds of Bacteria; Gram-positive and Gram-negative, were used. TEM observation of silver nanoparticles showed their shape, and size distribution. The particles were very small (2–5 nm) and had narrow distribution. SEM images of treated fabrics indicated silver nanoparticles were well dispersed on the surfaces of specimens. WAXS patterns did not show any peak of silver as the fabric had very small quantity of silver particles. However, ICP-MS informed the residual concentration of silver particles on fabrics before/after laundering. The antibacterial treatment of the textile fabrics was easily achieved by padding them with nanosized silver colloidal solution. The antibacterial efficacy of the fabrics was maintained after many times laundering.     

Characterization of silver nanoparticles synthesized on titanium dioxide fine particles

Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO(2) particles using a simple aqueous reduction method. The reducing agent used was NaBH(4); different molar ratios TiO(2):Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO(2) particles and that the TiO(2):Ag molar ratio plays an important role. We used three different TiO(2)Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80?nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO(2) particles.     

Green synthesis of silver nanoparticles using Glaucium corniculatum (L.) Curtis extract and evaluation of its antibacterial activity

The metal nanoparticles, due to interesting features such as electrical, optical, chemical and magnetic properties, have been investigated repeatedly. Also, the mentioned nanoparticles have specific uses in terms of their antibacterial activity. The biosynthesis method is more appropriate than the chemical method for producing the nanoparticles because it does not need any special facilities; it is also economically affordable. In the current study, the silver nanoparticles (AgNPs) were obtained by using a very simple and low‐cost method via Glaucium corniculatum (L.) Curtis plant extract. The characteristics of the AgNPs were investigated using techniques including: X‐ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy. The SEM and TEM images showed that the nanoparticles had a spherical shape, and the mean diameter of them was 53.7 and 45 nm, respectively. The results of the disc diffusion test used for measuring the anti‐bacterial activity of the synthesised nanoparticles indicated that the formed nanoparticles possessed a suitable anti‐bacterial activity.Inspec keywords: silver, nanoparticles, antibacterial activity, nanomedicine, nanofabrication, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectraOther keywords: green synthesis, silver nanoparticles, Glaucium corniculatum Curtis extract, antibacterial activity, metal nanoparticles, biosynthesis method, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, SEM, TEM, spherical shape, disc diffusion test, Ag     

Determination of essential work of fracture in EPBC sheets obtained by different transformation processes

1 mm sheets of polypropylene and ethylene-propylene block copolymers (EPBC) have been obtained using different processing methods in order to study the influence of processing induced morphology in the fracture properties of these materials. The processing methods employed were compression moulding (CM), extrusion-calendering (EC) and injection moulding (IM). Additionally, the sheets obtained by extrusion and injection were submitted to an annealing process with the aim to obtain more homogeneous morphologies that would ease their characterization.The morphology has been characterized by different techniques: Polarizing light microscopy (MLP), differential scanning calorimetry (DSC), wide-angle X-ray diffraction scattering (WAXS) and scanning electron microscopy (SEM).The fracture properties were determined by the essential work of fracture (EWF) method for deeply double edge notched specimens (DDENT), since these materials show ductile and post-yielding fracture behaviour. The EWF technique was applied in both the melt flow (MD) and the transversal (TD) directions in the sheets obtained by extrusion and injection moulding.Results show that the sensitivity of the technique allows examining the effect of morphological variations of thin sheets, as well as a better characterization of the orientation level (versus other parameters like yielding stress or elastic modulus obtained by tensile test).     

抗菌聚丙烯板的制备与性能

目的 制备一种具有抗菌性能的聚丙烯塑料板.方法 以乙酸铜(Cu(CH3COO)2·H2O)和乙酸锌(Zn(CH3COO)2·2H2O)为原料,通过固相反应,生成铜(Cu)接枝在纳米氧化锌(ZnO)上制成Cu/ZnO无机抗菌材料.将抗菌材料与聚丙烯粒料共混、造粒和模压成型制得抗菌聚丙烯板.对Cu/ZnO无机抗菌材料和抗菌聚丙烯板进行扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)、差示扫描量热仪(DSC)、X射线衍射仪(XRD)、电感耦合等离子体质谱(ICP)、抗菌实验和拉伸、弯曲强度测试,对材料的化学组成、结晶性、抗菌性、力学性能和安全性能进行表征分析.结果 采用抗菌母粒法制备的抗菌聚丙烯板,将抗菌剂分散均匀,抗菌剂的加入没有改变聚丙烯的化学结构.由于界面作用的存在,聚丙烯结晶温度升高,对熔融温度影响不大.力学性能测试表明,抗菌剂的加入使得聚丙烯板拉伸强度略有下降,弯曲强度呈现先上升后下降趋势;当抗菌剂质量分数为4％时,抗菌聚丙烯板具有最佳力学强度,且在此浓度下,抗菌聚丙烯对大肠杆菌和金黄色葡萄球菌的杀菌率均达到99.99％.金属离子在发挥抗菌作用时,迁移量远远低于欧盟规定允许的最大迁移量.结论 将通过固相反应制备的无机抗菌剂添加至聚丙烯粒料中制成抗菌聚丙烯板,将其进一步加工制成的果蔬周转箱可以有效减少箱体在运输中受到污染,如自身发霉长菌等现象,证明该材料具备食品包装的安全性.     

银型抗菌活性碳纤维的结构及其抗菌性能的研究

利用活性碳纤维的高效吸附性能 ,通过浸渍法把银、银盐等金属或金属化合物吸附沉积在活性碳纤维上 ,并对其进行适当处理 ,制备出含细小银化合物或金属银颗粒的活性碳纤维。利用扫描电镜 ,X 射线衍射 ,ICP发射光谱等分析测定方法研究了银型抗菌活性碳纤维的结构。研究了这类银型抗菌活性碳纤维对大肠埃氏杆菌 (Escherichiacoli)和金黄色葡萄球菌 (Staphylococlusaureus)的杀灭效果。结果表明 ,这类银型抗菌活性碳纤维对大肠杆菌和金黄色葡萄球菌均有很强的杀灭能力 ,经其处理后 ,水中的大肠杆菌和金黄色葡萄菌被完全杀灭。对每次使用后被洗脱的银含量测定表明 ,水中所含银浓度低于饮水标准的要求     

Preparation, characterization, and antibacterial activity of shell waste loaded with silver

A green inorganic antibacterial material was prepared using shell waste as a carrier material loaded with silver. It was characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (EDS), X-ray photoelectronic spectroscopy (XPS) and N₂ adsorption isotherms. The antibacterial activity was evaluated using Staphylococcus aureus and Escherichia coli as sensitive indicator strains. The antibacterial mechanism was probed and discussed as well. Silver carbonate was detected in the prepared material through XRD analysis. XPS measurement and EDS analysis also confirmed the loading of silver onto the carrier. The antibacterial test demonstrated that the prepared material had good antibacterial property, especially against E. coli. Based on the silver ion release and pH test, as well as comparatively analyzing the characteristics of carrier material and prepared material, we proposed that the antibacterial mechanism mainly involved the antibacterial activity of silver ion, slightly higher pH value and supplementary photocatalytic antibacterial activity of silver carbonate.     

Biosynthesis,characterisation and antimicrobial activity of silver and gold nanoparticles by Dolichos biflorus Linn seed extract

The bioreduction method employed for the synthesis of colloidal AgNPs and AuNPs is reported here. Methanolic and aqueous extracts of Dolichos biflorus Linn seed was used as the bio-reducing agent. The structural and morphological aspects of the synthesised metal nanoparticles were investigated using X-ray diffraction (XRD), energy-dispersive spectroscopy (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD, revealed crystalline nature of the synthesised particles, UV–vis spectrophotometric analysis showed characteristic absorption peak for both AgNPs and AuNPs. EDX analysis confirmed the presence of elemental silver and gold particles and the average size and morphology were determined by SEM and TEM. The synthesised AgNPs exhibited good antibacterial potential whereas AuNPs showed poor activity against human pathogenic, gram-positive bacteria such as Staphylococcus aureus, Bacillus subtilis and gram-negative bacteria, such as Escherichia coli, Pseudomonas aeruginosa.     

Antibacterial properties of padded PP/PE nonwovens incorporating nano-sized silver colloids

This paper deals with the effects that nano-sized silver colloids have on the antibacterial properties of PE/PP nonwovens against three kinds of bacteria: Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. These silver colloids comprise silver nanoparticles that are a non-toxic and non-tolerant disinfectant. PE/PP nonwovens are used as back sheets or coverstocks of baby diapers, adult diapers, sanitary napkins, and wipes. These materials are readily contaminated by bacteria present in moisture and dirt and can cause disease. We finished the nonwovens using a normal dipping–pad–dry method. From SEM images, we determined that the silver nanoparticles were generally dispersed well on the surface of the nonwoven fibers. We used the AATCC-100 test method to study the antibacterial properties of the treated fabrics. Bacteria were disinfected completely to below a count of 10 cells after 10 min when using the samples treated with 10 ppm of silver colloids. The ethanol-based silver/sulfur composite colloid (SNSE) has the best antibacterial efficacy when compared with the other nano-sized silver colloids. The silver particles having the smallest sizes gave the higher dispersibilities and the strongest antibacterial efficacies.     

Fracture resistance improvement of polypropylene by joint action of core-shell particles and nucleating agent

As a serial work about the fracture resistance improvement of polypropylene (PP), this work reports the joint effect of core-shell particles and nucleating agent (NA) on the microstructure and fracture resistance of PP. Core-shell particles were prepared through melt blending of ethylene-octene copolymer (POE) and calcium carbonate (CaCO₃). Different NA, i.e. α-form NA (P-tert-butylbenzoic acid-Al, MD-NA-28) and β-form NA (aryl amides compound, TMB-5) were introduced into PP matrix to control the crystalline structure. The phase morphology of POE and the distribution of CaCO₃ were characterized by using scanning electron microscope (SEM), and the crystallization behavior of PP matrix were investigated by using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarization optical microscope (POM). The mechanical properties were obtained through universal tensile measurement and notched Izod impact measurement. Surprisingly, the results show that through addition of so-called core-shell particles and NA simultaneously, the fracture resistance of PP can be dramatically improved.     

聚醚/双酚A环氧甲基丙烯酸酯复合光固化膜的性能

由聚醚型聚丙二醇二缩水甘油醚和甲基丙烯酸合成了可光固化的聚丙二醇二缩水甘油醚二甲基丙烯酸酯(DMA),再按不同质量配比将此合成物与双酚A型环氧甲基丙烯酸酯(BEMA)混合,经紫外光照射得到复合光固化膜,然后对所得固化膜的耐热性、柔韧性、硬度、光泽度、可见光透过率和微观形貌进行表征.研究结果表明,复合膜兼具DMA和BEM...     

有机硅/可膨胀石墨复合阻燃PP/TPU共混物的研究

为分析有机硅(Si)/可膨胀石墨(EG)对聚丙烯/热塑性聚氨酯/(PP/TPU)共混物性能的影响,通过差示扫描量热(DSC)、扫描电镜(SEM)、热重分析(TGA)、锥形量热仪(CONE)等表征方法对复合材料体系的结晶行为、热稳定性能、燃烧行为及残炭形貌特征进行了研究.结果表明:EG是一种有效的阻燃剂,能显著提高材料的阻燃性能;Si的存在对PP/TPU/EG复合材料有促进结晶作用,熔点增加,耐热性能得以提高,但Si的添加对复合材料体系的阻燃性能有一定的抑制作用,表明Si与EG复配在阻燃PP/TPU共混物时在阻燃效果上具有反协同效应.     

镀银碳纳米管的抗菌性研究

用离子束辅助沉积(IBAD)方法在碳纳米管表面制备银膜.用琼脂平板法测试了抗菌率,测试菌种为革兰氏阴性大肠杆菌(E.coil)和革兰氏阳性金黄色葡萄球菌(S.aureus);用扫描电子显微镜(SEM) 观测了镀银碳纳米管的微观形貌;用能量散射X射线谱(EDX)分析了镀银碳纳米管表面元素的原子百分比;用X射线光电子能谱(XPS) 分析了镀银碳纳米管的表面元素的价态.研究结果表明,镀银碳纳米管具有优良的抗菌性能,且比在热解碳上镀银样品的抗菌性强.     

Crystallization of carbon fibre reinforced polypropylene

Polypropylene (PP) was compounded with carbon fibre of various contents (0, 5, 10, 15, 20 vol%) using a single and a twin screw extruder. The influence of both the carbon fibre content and the compounding method on the thermal behaviour and characteristics of crystallization was studied using differential scanning calorimetry (DSC), polarizing optical microscopy and scanning electron microscopy (SEM). Melting and crystallization temperatures increased with the amount of carbon fibre. Isothermal crystallization was observed using DSC and it was found that crystallization was accelerated by the presence of carbon fibres. Using polarizing optical microscopy, it was found that the nucleation of polypropylene started at the crossing point of two or more fibres.     

One-step synthesis of reduced graphite oxide–silver nanocomposite

Here, a general approach for the preparation of reduced graphite oxide (rGO)–silver nanocomposite has been investigated. Graphite oxide (GO) sheets are used as the nanoscale substrates for the formation of rGO–silver composite. GO sheets and Ag ions can be reduced at the same time, under a mild condition using l-ascorbic acid (l-AA) as reducing agent. This simple approach should find practical applications in the production of rGO–silver nanocomposite. The SEM analysis indicates that the silver particles are dispersed on graphene sheets. Raman signals of rGO in the composite are increased by the attached silver nanoparticles, displaying surface-enhanced Raman scattering activity. The degree of enhancement can be adjusted by varying the quantity of silver nanoparticles in the composite. In addition, antibacterial activity of the composite against Escherichia coli was evaluated using zone of inhibition. Composites with Ag clearly showed antibacterial activity against E. coli. While GO alone has almost no effect against this bacteria.     

Evaluation of antimicrobial activity of synthesised silver nanoparticles using Thymus kotschyanus aqueous extract

Development of a green chemistry process for the synthesis of silver nanoparticles (AgNPs) has become a focus of interest. Characteristics of AgNPs were determined using techniques, such as ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy and X‐ray diffraction (XRD). The synthesised AgNPs using Thymus kotschyanus had the most growth inhibition against gram‐positive bacteria such as Staphylococcus aureus and Bacillus subtilise, while the growth inhibition of AgNPs at 1000–500 µg/ml occurred against Klebsiella pneumonia and at 1000–250 µg/ml of AgNPs was observed against E. coli. The UV–vis absorption spectra confirmed the formation of the AgNPs with the characteristic peak at 415 nm and SEM micrograph acknowledged spherical particles in a nanosize range. FTIR measured the possible biomolecules that are responsible for stabilisation of AgNPs. XRD analysis exhibited the crystalline nature of AgNPs and showed face‐centred cubic structure. The synthesised AgNPs revealed significant antibacterial activity against gram‐positive bacteria.Inspec keywords: visible spectra, microorganisms, ultraviolet spectra, biomedical materials, nanofabrication, nanoparticles, X‐ray diffraction, scanning electron microscopy, molecular biophysics, X‐ray chemical analysis, nanomedicine, silver, antibacterial activity, Fourier transform infrared spectraOther keywords: green chemistry process, ultraviolet–visible spectroscopy, gram‐positive bacteria, silver nanoparticles, Thymus kotschyanus aqueous extract, UV–vis spectroscopy, Fourier transform infrared spectroscopy, FTIR analysis, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, SEM micrograph, X‐ray diffraction, XRD, Staphylococcus aureus, Bacillus subtilise, Klebsiella pneumonia, E. coli, UV–vis absorption spectra, face‐centred cubic structure, antibacterial activity, antimicrobial activity, wavelength 415.0 nm, Ag     

Antibacterial Characterization of Silver Nanoparticles against E. Coli ATCC-15224

Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.     

新型石墨烯-聚苯胺-银基电极复合材料的制备及性能研究

目的设计一个低成本条件下成熟高效制备石墨烯-聚苯胺-银基复合电极材料的工艺路线。方法研究石墨烯的制备工艺以及石墨烯与聚苯胺、银粒子的复合效果,将石墨烯与苯胺、银粒子通过原位聚合的方法制得石墨烯-聚苯胺-银复合材料。利用扫描电子显微镜(SEM)、傅里叶变换-红外光谱(FT-IR)、X射线衍射(XRD)、循环伏安法(CV)和恒电流充放电法(GCD)对石墨烯和石墨烯-聚苯胺-银复合材料的形貌、结构和电化学性能进行分析研究。结果 SEM、FT-IR、XRD等测试表明,聚苯胺类衍生物、石墨烯以及银粒子在整个复合材料中共存。结论 CV和GCD的测试结果表明复合材料有优良的电化学性能,比电容最高可达到293 F/g。     

Preparation of silver iodide nanoparticles using laser ablation in liquid for antibacterial applications

In this study, the authors reported the first synthesis process of silver iodide (AgI) nanoparticles (NPs) by pulsed laser ablation of the AgI target in deionised distilled water. The optical and structural properties of AgI NPs were investigated by using UV–vis absorption, X‐ray diffraction, scanning electron microscope (SEM), energy dispersive X‐ray, Fourier transform infrared spectroscopy, and transmission electron microscope (TEM). The optical data showed the presence of plasmon peak at 434 nm and the optical bandgap was found to be 2.6 eV at room temperature. SEM results confirm the agglomeration and aggregation of synthesised AgI NPs. TEM investigation showed that AgI NPs have a spherical shape and the average particle size was around 20 nm. The particle size distribution was the Gaussian type. The results showed that the synthesised AgI NPs have antibacterial activities against both bacterial strains and the activities were more potent against gram‐negative bacteria.Inspec keywords: antibacterial activity, nanoparticles, X‐ray chemical analysis, particle size, transmission electron microscopy, X‐ray diffraction, nanofabrication, scanning electron microscopy, visible spectra, ultraviolet spectra, silver compounds, pulsed laser deposition, Fourier transform infrared spectra, optical constants, energy gap, aggregationOther keywords: synthesis process, pulsed laser ablation, AgI target, deionised distilled water, optical properties, structural properties, UV–vis absorption, X‐ray diffraction, transmission electron microscope, optical data, optical bandgap, antibacterial activities, silver iodide nanoparticles, energy dispersive X‐ray analysis, SEM, wavelength 434.0 nm, temperature 293 K to 298 K, AgI