In the best of our knowledge and based on our literature search, there are very few reports on hard magnetic polymeric nanocomposites. Therefore, we studied the magnetic interaction between the nanoparticles surrounded by polymeric chains. This interaction leads to a remarkable increase (from 5070 Oe to 5600 Oe) of nanoparticle coersivities relative to pure strontium ferrite nanoparticles. The hysteresis loops for ABS/SrM, PS/SrM, CA/SrM and PC/SrM are illustrated in Figs. 7-10 respectively.
Fourier transform infrared (FTIR) spectra were recorded on a Vertex 70 spectrometer with KBr pellets (Bruker Corpora- tion, Billerica, MA, USA). Ultraviolet-visible spectra were run on a Lambda 35 instrument (Perkin-Elmer, Waltham, MA, USA). The silver content in the nanocomposites was determined using the atomic absorption analysis method (AAnalyst 200 instrument, Perkin Elmer). Microphotographs were obtained using a transmission electron microscope (Leo 906E, Zeiss, Oberkochen, Germany). X-ray diffrac- tion patterns were obtained on a powder diffractometer (D8 Advance, Bruker Corporation). Thermogravimetric analysis and differential scanning calorimetry were per- formed using an STA 449 Jupiter derivatograph (Netzsch, Selb, Germany) in an atmosphere of air at a heating rate of 10 ° C per minute from 25 ° C to 700 ° C, the weight of the samples was 5 mg. The sedimentation stability of the sols was evaluated visually and by ultraviolet-visible spectra.
Silver nanostructures as an effective antibacterial materials were synthesized via three various hydrothermal, sono-chemical and microwave methods using water as a green solvent. Then Chitosan-Ag polymer based nanocomposites were made by a fast chemical procedure. The influence of power, temperature and time on the morphology and particle size of the products was investigated. Scanning electron microscopy (SEM) approved that mono-disperse nanoparticles were achieved using all three procedures. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy confirmed preparation of pure products. The antibacterial behaviour of Chitosan-Ag nanocomposites was evaluated using degradation of E coli bacteria. The results show a nanocomposite with applicable antibacterial performance in burn wounds.
It is observed that SAXS pattern of nano CdS dispersed polymeric blend matrices show higher scattering in- tensity as compared to their counterpart without CdS dispersed samples. This is attributed due to the fact that the CdS nanoparticle takes position at the voids site in respective blend matrix. There they act as independent scat- tering centers and contributes by enhancing scattering intensity in the respective nanocomposites’s SAXS pat- tern.
nanomaterials in the enhancement of the physicomechanical properties of limestone monuments, the aim of the present work being to evaluate comparatively the effectiveness of nanoparticles as consolidation and protection material for limestone artworks. The nanoparticles were added to an acrylic-based copolymer (polyethylmethacrylate (EMA)/methylacrylate (MA) (70/30), in order to improve its physiochemical and mechanical properties, and produced a significant improvement in the ability of the polymers to consolidate and protect the stone. The synthesis process of nanoparticles/polymer nanocomposite has been prepared by an in situ emulsion polymerization system. The nanocomposites contained poly (EMA/MA) with a solid content of 3% [poly (EMA/MA)] in the absence and presence of 5% nanoparticles (0.15 g nanoparticles). Samples were subjected to artificial aging by relative humidity/temperature and acid/salt crystallization weathering to show the optimum conditions of durability and the effectiveness of the nano-mixture in improving the physical and mechanical properties of the stone material. To ensure that the treatment had no negative effects on the physical characteristics of the limestone, the properties of the treated limestone samples were evaluated comparatively before and after artificial aging by the conduct of microstructural (phase morphology studied by means of scanning electron microscopy) and aesthetic (colour and lightness measured by spectrophotometry) analyses. Also used were measurement of static contact angle of water droplets on the surface of the samples, total immersion water absorption, compressive
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In this study, we have reported a synthesis of new hydro- philic nontoxic nanocomposites containing AgNPs in a functional polymer matrix of poly (1-vinyl-1,2,4-triazole-co- N-vinylpyrrolidone). The reduction of silver ions in the pres- ence of copolymer containing triazole and lactam groups, as the stabilizing matrix, leads to the formation of mono- dispersed AgNPs with a narrow size distribution (2–6 nm). The AgNP nanocomposites obtained are thermally stable up to 270 ° C and highly stable. Due to the effective stabili- zation by functional groups, AgNPs do not precipitate and or change in size even after storage in aqueous solutions for 4 months. The toxicity of the initial poly (VT-co-VP) copolymer and nanocomposite containing AgNPs has
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2.3. Synthesis of Epoxy/AlN Micro and Nanocomposites Using Casting Technique Epoxy/AlN micro and nanocomposites were prepared us- ing casting technique, initially; required quantity of AlN powder was added to the epoxy resin and stirred. Then the hardener TETA of desired amount was added to the epoxy/AlN mixture and resulting mixture was stirred vigorously to ensure homogenous dispersion of the AlN within the epoxy matrix. Finally, the mixture was poured onto stainless steel mold, pre-cured in an oven at 135˚C for 3 h and then maintained for 12 h at ambient tempera- ture. The post curing was carried out at 80˚C for 2 h, 100˚C for 1 h and 120˚C for 2 h respectively. Then the mold were left in the oven and allowed to cool gradually to room temperature. Similar procedure was also em- ployed for preparation of epoxy/AlN nanocomposite. In case of epoxy/AlN microcomposites both surface-treated and untreated AlN have been fabricated. The composi- tions in both surface-treated and untreated epoxy/AlN composites are maintained the same as shown in the Ta- ble 1. Various compositions prepared have been high- lighted in the Table 1.
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destroy or prevent the growth of fungi. The most common types are mycoses such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as Cryptococci meningitis. The antibacterial and antifungal activity of citric and tartaric acid nano composites against all tested Bacteria and fungi, as measured by agar dilution test, was presented in Table 1,2,3,4. All of the Bacterial and fungal organisms tested were affected by citric and tartaric acid nanocomposites. Citric acid was active against all pathogenic bacteria and fungi tested. Conversely, tartaric acid showed modest activity against all bacteria and fungi tested. The higher activity of citric acid may be attributed to have several inhibitory mechanisms such as depression of internal pH of microbial cell by ionization of undissociated acid molecules and disruption of substrate transport by altering cell membrane permeability or reduction of proton motive force (Jay, 2000; Atabay and Corry, 1997). Conversely, tartaric acid, as an antimicrobial agent, is believed to act only by lowering the pH of the cell (Blaszyk and Holley, 1998). In addition to the inhibition of energy production, tartaric acid prevents the production of malic acid, which is a key intermediate in the production of glucose in the process of gluconeogenesis, the principal fuel for the cells (Anaissie et al., 2003). Several studies showed that citric acid and its salts inhibit the growth of the most common bacterial pathogens such as Arcobacter spp., Campylobacter spp., lactobacilli, E. coli O157:H7 and L. monocytogenes (Coste et al., 2007). This study showed that citrate salt was active against Gram-positive species but showed little activity against Gram-negative species; acetate salt showed the opposite results.
Abstract: Graphene Magnetic Polymeric Nanocomposites-Array sensor is successfully detecting human brain tumour based on Specific Absorption Rate technique. The technique associated with low cost, non-invasive and accurate in detecting tumour. The sensor consists of graphene as the radiating element and Polydimethylsiloxane Ferrite as the substrate in order to realize ultra-wide band radiation (2.5 GHz-12.2 GHz) with high energy (2.5dB- 6.7dB) in microwave frequency ranges. Amount of energy absorbed by the human brain indicated the present of tumour. Human brain with tumour absorbed more energy and recorded higher SAR value (2.56 W/kg) compared with human brain without tumour (1.07 W/kg).
Fabrication of nanocomposites from immiscible polymer blend system has been represented in this work. A new type of natural clay named Halloysite Nanotubes (HNTs) are modified by Polyethyleneimine (PEI) and these PEI grafted HNTs are incorporated into the immiscible blend system during melt mixing process to prepare halloysite based nanocompo- sites. Fourier Transform Infrared Spectroscopy (FTIR) study confirms the formation of PEI grafted HNTs. The nano- composites are characterized by SEM for morphological study and, the dispersion manners of nanoclays by Transmis- sion Electron Microscopy (TEM). Storage modulus is studied by Dynamic Mechanical Thermal Analysis (DMTA) in- strument. The tensile measurement explored better tensile property of nanocomposites as compared to the virgin blend. XRD is performed to determine the crystalline behavior of the nanocomposites as well as for blend. The above investi- gations reveal that the HNTs act as reinforcing as well as nucleating agent in the blend system.
It is clearly seen that the increase in the onset of decomposition occurs for nanocomposites at low filler content when the heating takes place in air atmosphere. In our research this phenomenon can easily be observed in the case of a filler con- tent of 1.5 wt.% for PP/MMT-EA nanocomposites and of 3 wt.% for PE/MMT-EA, when interca- lating an organoclay is well compatible with the polymer. This is another very much desired char- acteristic of nanocomposites in which the thermal properties’ improvement corresponds with a low filler content, often making the obtained material cheaper, lighter and easier to process than more conventional microcomposites. Another key fac- tor that may determine the extent of the thermal stabilization in nanocomposites could also arise
In this study, a new nanocomposite based on Polyvinylalcohol/Polyaniline/Zinc oxide (PVA/PANi/ ZnO) was successfully synthesized. ZnO powder was used to produce its nanoparticles (NPs) using conventional method. PVA/PANi composite was used to produce ZnO NPs. Polyaniline was synthe- sized in sol solution of PVA in the presence of ammonium persulphate. Morphology and the size of ZnO NPs in nanocomposites were studied via Scanning Electron Microscopy (SEM), X-ray Diffrac- tion (XRD) analysis and Infrared (IR) spectroscopy. According to XRD results, the average size of prepared ZnO NPs was found to be at the range 22 - 34 nm. SEM images were shown hexagonal shape for ZnO NPs, which was used for the investigation of antibacterial property. Finally, the an- tibacterial activity of the prepared ZnO NPs and nanocomposites was evaluated against two bacte- ria of Gram positive Staphylococcus aureus and Gram negative Escherichia coli using paper disc diffusion method. The results were shown that the prepared nanocomposites were effective against two bacteria.
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It was found that, regardless of the technological history and crystal structure of the starting semi-dispersed particles form the cluster structures, and consisting of single particles with nanoscale parameters. This single particle morphology characterized by the presence of nanoscale spherical elements, plate or whisker habit forming nanorelief surface layer, contributing to the formation of the boundary layer at the interfacial interactions of the components in the formation of the nanocomposite material. Specific nanorelief surface layer due to crystal-chemical and technological prerequisites, is predominant factor in the choice of the original semi-finished product and technology of dispersed particles with optimal dimensional parameters. This dispersion of particles of a modifier can be in the range of micro, providing the necessary modifying effect due to the presence of nano relief with a characteristic structure forming elements. With this practical production nanocomposite materials based on polymeric matrices may use available intermediates, for example, silicon and carbon- containing minerals, with the widespread use of high-dispersion technologies.
manufacture of nanoparticles intended for drug delivery. Of these, PLA and PLGA have been approved for human use by the Food and Drug Administration (FDA). A wide range of drugs of different hydrophilicity or hydrophobicity can be incorporated into these polymers, and their release char- acteristics can be tailored to meet dosing requirements. The performance of the polymer can be adapted to the intended application by controlling the molecular weight or copolymer composition which influences properties such as degradation rate, thermal sensitivity, and pH sensitivity. These polymers have the capability to sustain drug release for several weeks. Drug loading is generally achieved by encapsulation, entrap- ment, or dissolution/dispersion. The biodegradable and biocompatible properties of polymeric nanoparticles make them very attractive candidates for drug delivery, tissue engineering, and biomedical applications.
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Nano-composites are the materials with one bulk phase and the others are dispersed in that bulk phase are small nano scale particles which are used to enhance the properties of the bulk phase. These nano scale particles are may be of one type or may be of different types are used to tailor made the properties of the bulk material/phase. The properties of the nanocomposites differ from the individual atoms and molecules or bulk matter. The controlling of the nanoparticles can control the properties of the materials like physical properties, mechanical properties 3,16,18 , chemical properties, biological properties, melting temperature,
Carbon nanotubes (CNTs) have attracted particular interest because of their remarkable mechanical and electrical properties . The combination of these prop- erties with very low densities suggests that CNTs are ideal candidates for high-performance polymer compo- sites . In order to increase the application range of polymers, highly conductive nanoscale fillers can be incorporated into the polymeric matrix. As CNTs pre- sent high electrical conductivity (10 3 -10 4 S/cm), they have been widely used . Therefore, CNT/polymer composites are expected to have several important applications, namely, in the field of sensors and actua- tors . However, in order to properly tailor the com- posite material properties for specific applications, the relevant conduction mechanisms must be better understood.
The improvements in the mechanical properties of PET/graphene nanocomposites could possibly be attributed to the superior mechanical properties displayed by the graphene sheets or their high surface area [2, 4, 16, 40-44]. To differentiate between these effects, PET with 0.07 wt% graphite was melt blended in the same conditions (Figure S4, Supporting Information). The results showed that the ultimate tensile strength decreased by approximately 50%. This shows the importance of filler thickness, which in our case is related to the exfoliation state, and it also implies that filler surface area may be important.
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Abstract:- The definition of nanocomposites has broadened significantly to encompass a large variety of systems such as one-dimensional, two-dimensional, three-dimensional and amorphous materials, made of distinctly dissimilar components and mixed at the nanometer scale. This research presents a detailed definition of nanocomposites, its origin, classification, properties, benefits, as well as its future. With the proper choice of compatibilizing chemistries, the nanometer-sized clay platelets interact with polymers in unique ways. The paper shows that the application possibilities for packaging include food and non-food films and rigid containers. In the engineering plastics arena, a host of automotive and industrial components can be considered, making use of lightweight, impact, scratch-resistant and higher heat distortion performance characteristics. In plastics the advantages of nanocomposites over conventional ones don’t stop at strength. The high heat resistance and low flammability of some nanocomposites also make them good choices to use as insulators and wire coverings.
computer chip packaging (insulation), protective coatings, adhesives and advanced aerospace composites, based on their great strength, high temperature stability, good processability, and good chemical resistance these are theimportant applications for polymer nanocomposites. Also polymer nanocomposites show major improvements in mechanical properties, gas barrier properties, thermal stability, fire retardancy, insulating properties with good mechanical properties and other fields [4-6].
The crystalline nature of synthesized nanocomposites was identified using X-ray diffractogram (XRD) pattern (fig. 5).The diffractogram pattern was indexed properly for all crystalline peaks and compared with JCPDS data file. Figure (5) shows the major peaks at 2θ values of 25.36°, 38.01°, 47.98°, 54.76° which corresponds to the planes of (101), (004), (200), and (211) of tetragonal anatase TiO 2 (JCPDS Card No. 21-1272) ,. The peaks at 2θ values of 37.26°, 44.76°, 64.85° correspond to the planes of (111),
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