Preparation and study on the optical, mechanical, and antibacterial properties of polylactic acid/ZnO/TiO2 shared nanocomposites

2020 ◽  
Vol 36 (3) ◽  
pp. 285-311
Author(s):  
Ali Tajdari ◽  
Amir Babaei ◽  
Alireza Goudarzi ◽  
Razie Partovi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Optical Properties ◽  
Polylactic Acid ◽  
Field Emission ◽  
Antibacterial Properties ◽  
Hydrolytic Degradation ◽  
Scanning Electron

In this research, first, ZnO nanorods were synthesized by hydrothermal method and characterized in terms of morphological and structural properties by means of field emission scanning electron microscopy, Fourier transform infrared, and X-ray diffraction techniques. Subsequently, polylactic acid/ZnO, polylactic acid/TiO2, and polylactic acid/ZnO/TiO2 nanocomposites with different percentages of nanoparticles and two different types of ZnO morphologies were prepared and their microstructural, optical, mechanical, hydrolytic degradation, and antibacterial properties were investigated. Field emission scanning electron microscopy results of polylactic acid/ZnO and polylactic acid/TiO2 samples showed a proper dispersion and nanoparticle distribution for low percentages (up to 5 wt%) and increased aggregation for the higher percentages. Besides, a large increase in the aggregation tendency was observed for combined nanoparticles (polylactic acid/ZnO/TiO2 nanocomposites). Results of the tensile test, the UV–Vis absorption tests, and the hydrolytic degradation tests of the samples showed an enhanced mechanical (approximately 55% increase in the presence of 3–5 wt% of nanoparticles) and light absorption and degradation (approximately 85% increase in the presence of 3–10 wt% of nanoparticles) for the polylactic acid by incorporating nanoparticles. It was also observed that, in addition to the quality of dispersion and distribution of nanoparticles in the polymeric matrix, the type of morphology of nanoparticles can contribute to the improvement of these properties. The cylindrical morphology of ZnO played a greater role on improving the polylactic acid mechanical properties compared to the spherical ZnO morphology (approximately 20%). On the contrary, the increased polylactic acid optical properties and degradation with ZnO spherical morphology were more pronounced (approximately 60%). Interestingly, when both ZnO and TiO2 were added, a synergistic effect in the case of UV-shielding and degradation rate and alternatively, a detrimental effect on the mechanical properties were detected. (The polylactic acid optical properties increased by about 17% and its degradation more than doubled.) Furthermore, the antibacterial activity of polylactic acid was investigated against the two Gram-positive Listeria monocytogenes and Gram-negative bacteria Escherichia coli by incorporating nanoparticles. The results indicated that as the nanoparticle percentage increases, the antibacterial activity steadily increases.

scholarly journals A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Buzuayehu Abebe ◽  
Enyew Amare Zereffa ◽  
Aschalew Tadesse ◽  
H. C. Ananda Murthy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Field Emission ◽  
Volume Ratio ◽  
Electronic Configuration ◽  
Microscopic Investigation ◽  
Electron Microscopic ◽  
Active Materials ◽  
Scanning Electron

Abstract Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

scholarly journals Antibacterial activity of zinc oxide nanoparticles obtained by pulsed laser ablation in water and air

2018 ◽  
Vol 243 ◽  
pp. 00017 ◽  
Author(s):  
Daria Goncharova ◽  
Ekaterina Gavrilenko ◽  
Anna Nemoykina ◽  
Valery Svetlichnyi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Laser Ablation ◽  
Zno Nanoparticles ◽  
Antibacterial Properties ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Composition And Structure ◽  
Scanning Electron

The paper studies physicochemical and antibacterial properties of ZnO nanoparticles obtained by pulsed laser ablation in water and air. Their composition and structure were studied by X-ray diffraction, transmission and scanning electron microscopy. Antibacterial activity of the nanoparticles was examined by its affection on Gram-positive Staphylococcus aureus (S.aureus). The dependence of nanoparticles’ physical and chemical antibacterial properties on the conditions of the ablation was shown. The model materials for the antibacterial bandage were made of cotton, filter paper and biodegradable polymer scaffolds (poly-l-lactide acid), and then they were coated with the obtained ZnO nanoparticles. The model bandage materials were examined by the scanning electron microscopy method and their antibacterial activity (ISO 20743:2013) was determined. High activity of all the samples against S.aureus was proved.

Evaluation of mechanical properties of 1050-Al reinforced with SiC particles via accumulative roll bonding process

2018 ◽  
Vol 53 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Adel Fathy ◽  
Dalia Ibrahim ◽  
Omayma Elkady ◽  
Mohammed Hassan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Microstructural Evolution ◽  
Accumulative Roll Bonding ◽  
Bonding Process ◽  
Accumulative Roll Bonding Process ◽  
Roll Bonding ◽  
Scanning Electron

Accumulative roll bonding was successfully used as a severe plastic deformation method to produce Al–SiC composite sheets. The effect of the addition of SiC particles on the microstructural evolution and mechanical properties of the composites during accumulative roll bonding was studied. The Al–1, 2 and 4 vol.% SiC composite sheets were produced by accumulative roll bonding at room temperature. Monolithic Al sheets were also produced by the accumulative roll bonding process to compare with the composite samples. Field emission scanning electron microscopy revealed that the particles had a random and uniform distribution in the matrix by the last accumulative roll bonding cycles, and strong mechanical bonding takes place at the interface of the particle matrix. This microstructural evolution led to improvement in the hardness, strength and elongation during the accumulative roll bonding process. It is also shown that by increasing the volume fraction of particles up to 4 vol.% SiC, the yield and tensile strengths of the composite sheets increased more than 1.2 and 1.3 times the accumulative roll-bonded aluminum sheets, respectively. Field emission scanning electron microscopy observation of fractured surface showed that the failure broken of composite was shear ductile rupture.

Effect of ABS/PMMA/EMA ternary blending sequence on mechanical properties and surface glossiness

2016 ◽  
Vol 36 (6) ◽  
pp. 625-633 ◽  
Author(s):  
Jin Ding ◽  
Zhen Ming Yue ◽  
Jiao Sun ◽  
Ji Cui Zhou ◽  
Jun Gao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Optical Properties ◽  
The Other ◽  
Scanning Calorimetry ◽  
Izod Impact ◽  
Blending Sequence ◽  
The Impact ◽  
Scanning Electron

Abstract Acrylonitrile-butadienestyrene (ABS)/poly(methylmethacrylate) (PMMA)/ethylene methacrylate (EMA) composites were prepared with different blending sequences. All ABS/PMMA/EMA copolymers were designed to achieve the same total chemical composition, in which ABS/PMMA was equal to 80/20 and EMA was fixed at 6 wt%. The effects of different blending sequences on the mechanical and optical properties of ABS/PMMA/EMA blends were investigated. Results indicated that the tensile strengths of ABS/PMMA/EMA blends with different blending sequences were slightly affected, whereas the Izod impact strength of blends significantly varied. The impact toughness of the blends, in which PMMA/EMA was initially blended and then combined with ABS, was approximately twice that of the other blends. This blending sequence also had surface glossiness that was superior to those of the other blends. Differential scanning calorimetry and scanning electron microscopy further revealed that blending sequence influenced the phase miscibility and dispersion of the blends, which led to different mechanical and optical properties.

scholarly journals Electrospun VDF-TeFE Scaffolds Modified by Copper and Titanium in Magnetron Plasma and Their Antibacterial Activity against MRSA

Technologies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Arsalan D. Badaraev ◽  
Marat I. Lerner ◽  
Dmitrii V. Sidelev ◽  
Evgeny N. Bolbasov ◽  
Sergei I. Tverdokhlebov
Keyword(s):  
Electron Microscopy ◽  
Tissue Engineering ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Vinylidene Fluoride ◽  
Fiber Diameter ◽  
Antibacterial Properties ◽  
Argon Atmosphere ◽  
Copolymer Solution ◽  
Scanning Electron

Copolymer solution of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) was used for electrospinning of fluoropolymer scaffolds. Magnetron co-sputtering of titanium and copper targets in the argon atmosphere was used for VDF-TeFE scaffolds modification. Scanning electron microscopy (SEM) showed that scaffolds have a nonwoven structure with mean fiber diameter 0.77 ± 0.40 μm, mean porosity 58 ± 7%. The wetting angle of the original (unmodified) hydrophobic fluoropolymer scaffold after modification by titanium begins to possess hydrophilic properties. VDF-TeFE scaffold modification by titanium/copper leads to the appearance of strong antibacterial properties. The obtained fluoropolymer samples can be successfully used in tissue engineering.

scholarly journals INFLUENCE OF POLYETHYLENE OXIDE CONTENT ON SOME CHARACTERISTICS OF PLA/CS FILMS LOADING NIFEDIPINE

2017 ◽  
Vol 55 (6) ◽  
pp. 716 ◽  
Author(s):  
Nguyen Thuy Chinh ◽  
Trang Thi Thu Nguyen ◽  
Mai Thi Tran ◽  
Cong Van Do ◽  
Huynh Duc Mai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Polylactic Acid ◽  
Field Emission ◽  
Polyethylene Oxide ◽  
Oxide Content ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Scanning Electron

This work mentions the effect of polyethylene oxide (PEO) content on some characteristics and properties of polylactic acid (PLA)/chitosan (CS) films loading nifedipine (NIF). The water contact angle, droplet size values and Field Emission Scanning Electron Microscopy (FESEM) images  of the films are used to investigate their morphology and hydrophobicity. The obtained results show that the hydrophobic property of the PLA/CS/NIF films is improved by the presence of PEO. Besides, the PLA/CS/NIF films containing PEO have tighter structure and water absorbed ability less than those of the PLA/CS/NIF films

High-resolution scanning electron microscopy of carbon fiber

1989 ◽  
Vol 47 ◽  
pp. 704-705
Author(s):  
Deborah L. Vezie
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Carbon Fiber ◽  
Field Emission ◽  
Carbon Fibers ◽  
Low Voltage ◽  
Electron Gun ◽  
Scanning Electron

As part of an extensive study of polyacrylonitrile (PAN) and mesophase pitch-based carbon fibers, high resolution scanning electron microscopy (HRSEM) is shown to provide additional insight into understanding and modelling microstructural origins of mechanical properties of carbon fiber. Although carbon fiber has been studied extensively, no sufficiently clear relationship between structure and mechanical properties such as elastic modulus and compressive strength has yet been developed from quantitative TEM and WAXS investigations.In this study, HRSEM data of selected carbon fibers is used to illustrate the power of HRSEM to elucidate structural differences likely accounting for changes in mechanical properties not sensitively probed either by TEM or WAXS. The three-dimensional nature of SEM imaging with accompanying high resolution permits a clearer visualization and more detailed examination of regional structures within carbon fiber over two-dimensional TEM and globally averaged WAXS data.The design of the high resolution, field emission SEM permits low voltage imaging of poorly conducting samples with resolution an order of magnitude greater than a conventional tungsten hairpin filament SEM under the same operating voltage and sample preparation conditions. Although carbon fiber is a relatively conductive material, charging effects can be seen in uncoated PAN fibers above 3.0 keV in a conventional SEM. Lower accelerating voltages are necessary for uncoated imaging of these fibers, but become impractical due to degradation of conventional SEM performance at these voltages. Uncoated sample imaging is preferred to prevent conventional evaporation or sputter coating techniques from obscuring or altering the sample surface, although charging effects may then be a problem. The high resolution, field emission SEM solves these competing voltage/ charging/ resolution issues for poorly conducting materials with the very nature of its design; the high brightness of the electron gun at low voltage coupled with the “in lens” sample placement and above the objective lens detector dramatically improve the resolution of these instruments, especially at low voltage.

Acidolysis Effect on Starch in Polylactic Acid (PLA)/Thermoplastic Starch (TPS) Blend

2017 ◽  
Vol 264 ◽  
pp. 156-159
Author(s):  
Noorizzah Ibrahim ◽  
Mohamad Kahar Ab Wahab
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Surface Tension ◽  
Polylactic Acid ◽  
Interfacial Adhesion ◽  
Thermoplastic Starch ◽  
The Other ◽  
Elongation At Break ◽  
Scanning Electron

In this research, the Thermoplastic Starch (TPS) is blended with Polylactic Acid (PLA). By treating TPS with CA, the interfacial adhesion of PLA/TPS blend was also being improved. The ratio between PLA/TPS was chosen at 60/40 and 40/60 and CA contents were varied from 0%, 3%, and 6%. After acidolysis of TPS by CA, the tensile strength (60/40) and (40/60) of the PLA/TPS blend were found to increase. However, the elongation at break of PLA/TPS (60/40) blend was lower compared to PLA/TPS (40/60) blend. Higher loadings of TPS in the blend tend to make the blend elongate due to the flexibility of TPS after CA modification. On the other hand, by modifying the TPS with CA, the surface tension at the PLS/TPS interface had been reduced. This can be seen through micrograph that obtained from scanning electron microscopy. Different CA content in PLA/TPS blend showed the dispersed or co-continuous structure, which were related with the mechanical properties.

A New Image Processing Technique for STEM

1974 ◽  
Vol 32 ◽  
pp. 432-433
Author(s):  
Yasushi Kokubo ◽  
Hirotami Koike ◽  
Teruo Someya
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Elastic Scattering ◽  
Field Emission ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Energy Analyzer ◽  
Scanning Microscope ◽  
Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

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