scholarly journals Novel Cationic Polyurethane Surfactants Containing Saturated Chains- Part 1: Synthesis, Characterization and Surface Activity

2018 ◽  
pp. 1-14
Author(s):  
Nasser R. Abd El-Rahman Taiea ◽  
Mona A. Youssif ◽  
Nabel A. Negm
Keyword(s):  
Saturated Fatty Acids ◽  
Ultra Violet ◽  
Toluene Diisocyanate ◽  
Molecular Weights ◽  
Surface Activities ◽  
Polymeric Surface ◽  
Surface Active Agents ◽  
Transmission Electron ◽  
Triethanol Amine ◽  
Silver Nanocomposite

Novel cationic polymeric surfactants were synthesized throughout the reaction of monoester of triethanol amine and two saturated fatty acids (palmitic acid and stearic acid) and TDI (toluene diisocyanate). The obtained polyurethane (PU) then was reacted by acetyl chloride to yield the desired surfactants. The structures of the produced compounds were described by using Fourier Transform Infrared Spectroscopy (FTIR) and their average molecular weights. Silver nanocomposite of the prepared cationic PU surfactants were characterized via physical combination by chemically prepared silver nanoparticles. The structure of the silver composite was determined using: Ultra-violet spectroscopy, Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS) spectroscopy. The effect of the hydrophobic chains on the surface activities of the synthesized cationic polymeric surface active agents and their silver nanocomposite was studied.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

scholarly journals A Facile Urea-Assisted Thermal Decomposition Process of TiO2 Nanoparticles and Their Photocatalytic Activity

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 165
Author(s):  
Sandip Madhukar Deshmukh ◽  
Mohaseen S. Tamboli ◽  
Hamid Shaikh ◽  
Santosh B. Babar ◽  
Dipak P. Hiwarale ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Large Scale ◽  
Ultra Violet ◽  
Tio2 Nps ◽  
Transmission Electron ◽  
Structures And Properties ◽  
Ft Ir ◽  
Large Scale Synthesis

In the present work, we have reported a facile and large-scale synthesis of TiO2 nanoparticles (NPs) through urea-assisted thermal decomposition of titanium oxysulphate. We have successfully synthesized TiO2 NPs by using this effective route with different weight ratios of titanium oxysulphate: urea. The structures and properties of TiO2 NPs were confirmed by scanning electron microscope) (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy (UV-vis), and photoluminescence (Pl) techniques. XRD demonstrated that TiO2 NPs holds of anatase crystal phase with crystallizing size 14–19 nm even after heating at 600 °C. TGA, SEM, and TEM images reveal urea’s role, which controls the size, morphology, and aggregation of TiO2 NPs during the thermal decomposition. These TiO2 NPs were employed for photodegradation of Methyl Orange (MO) in the presence of ultraviolet (UV) radiation. An interesting find was that the TiO2 NPs exhibited better photocatalytic activity and excellent recycling stability over several photodegradation cycles. Furthermore, the present method has a great perspective to be used as an efficient method for large-scale synthesis of TiO2 NPs.

scholarly journals Citrus Lemon Juice Mediated Preparation of AgNPs/Chitosan-Based Bionanocomposites and Its Antimicrobial and Antioxidant Activity

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
S. Rajeshkumar
Keyword(s):  
Infrared Spectroscopy ◽  
Fungal Pathogens ◽  
Near Infrared ◽  
Lemon Juice ◽  
Advanced Materials ◽  
Atomic Force ◽  
Transmission Electron ◽  
Silver Nanocomposite ◽  
Antioxidant And Antimicrobial Activity ◽  
Antimicrobial And Antioxidant Activity

Nanoparticles are important advanced materials with numerous uses in a variety of fields. Novel antibacterial nanocomposites with synergistic capabilities can be created by combining metal nanoparticles with biopolymers of various functionalities. This research evaluates an antimicrobial and antioxidant-rich chitosan-based silver nanocomposite synthesized by using citrus lemon extract as a reducing and capping agent. UV-vis spectrophotometer, scanning electron microscope, elemental dispersive analysis, X-ray diffraction assay, atomic force microscope, Fourier transform infrared spectroscopy, UV-near infrared spectroscopy, and transmission electron microscopy were used to characterize the chitosan-based silver nanocomposite (CS-Ag nanocomposite). The nanocomposite synthesized is used to demonstrate antioxidant and antimicrobial activity against fungal pathogens.

Synthesis of Uniform and High Density Silver Nanoparticles by using Peltophorum pterocarpum flower Extract

2014 ◽  
Vol 1584 ◽  
Author(s):  
Matheswaran BALAMURUGAN ◽  
Shanmugam SARAVANAN ◽  
Naoki OHTANI
Keyword(s):  
Silver Nanoparticles ◽  
Fourier Transform ◽  
Electron Microscope ◽  
Ultra Violet ◽  
Capping Agent ◽  
Nanosized Particles ◽  
Flower Extract ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ft Ir

ABSTRACTSilver nanoparticle (AgNP) is one of the elegant material because its uses in various fields. In this study, AgNPs have been prepared by using Peltophorum pterocarpum (PP) flower extract as reducing and capping agent and aqueous silver nitrate (aq.AgNO3) as silver precursor. The synthesized nanoparticles were characterized using Ultra Violet - Visible (UV-Vis) spectroscopy, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscopy (FT-IR), which reveals the formation of nanosized particles. The UV-Vis spectrum shows an absorption peak around 430nm. HR-TEM images of AgNPs with clear morphology and well dispersed prepared AgNPs.

Click Synthesis of Shape-Persistent Azodendrimers and their Orthogonal Self-Assembly to Nanofibres

2018 ◽  
Vol 71 (6) ◽  
pp. 463 ◽  
Author(s):  
Tamer El Malah ◽  
Hany F. Nour
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Self Assembly ◽  
Molecular Structures ◽  
Side Chain ◽  
Spectroscopic Techniques ◽  
Molecular Weights ◽  
Transmission Electron ◽  
Click Synthesis ◽  
Scanning Electron

The copper(i)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction has been efficiently utilized to synthesize a series of dendrons with amino functionalities. The aminodendrons successfully underwent azodimerization to furnish a series of pyridyl- and phenyl-based azodendrimers with peripheral alkyl or ether side chain substituents. The molecular structures of the azodendrimers were fully assigned using different spectroscopic techniques, such as 1H NMR and 13C NMR, and the molecular weights were determined using MALDI-TOF mass spectrometry. The molecular self-assembly of the azodendrimers was investigated by scanning electron microscopy and transmission electron microscopy, which revealed the formation of highly ordered and uniform self-assembled nanofibres.

WO3:Mo and WO3:Ti Thin Films Deposited by Spray Pyrolysis: The Influence of Metallic Concentration on Physical Properties: An Electron Microscopy and Atomic Force Study

2019 ◽  
Vol 286 ◽  
pp. 49-63
Author(s):  
Dwight Acosta ◽  
Francisco Hernández ◽  
Alejandra López-Suárez ◽  
Carlos Magaña
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Ultra Violet ◽  
Surface Characteristics ◽  
Structural Defects ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Resolution Electron

WO3:Mo and WO3:Ti thin films have been deposited on FTO/Glass substrates by the pulsed chemical spray technique at a substrate temperature of Ts= 450°C. The influence of Mo and Ti doping on the structural, electrical, and optical behavior of WO3thin films, has been studied by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Ultra Violet and Visible Spectrometry (UV-VIS), and Surface Conductivity Methods (Four Points). Doped WO3films presents similar polycrystalline structures but with noticeable modifications in surface configurations at micrometric and nanometric levels, as the Mo and Ti concentration is systematically increased in the starting sprayed solution. From processed High-Resolution Electron Micrographs (HREM), a low density of structural defects was found on pure and doped WO3grains. This lead to conclude that variations in films surface characteristics are mainly related with metallic doping concentrations which in turn, have noticeable influence in electrical and optical behaviors reported in this work.

scholarly journals Improving the Damping Properties of Nanocomposites by Monodispersed Hybrid POSS Nanoparticles: Preparation and Mechanisms

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 647 ◽  
Author(s):  
Wei Wei ◽  
Yingjun Zhang ◽  
Meihua Liu ◽  
Yifan Zhang ◽  
Yuan Yin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Damping Factor ◽  
Damping Properties ◽  
Molecular Weights ◽  
Organic Hybrid ◽  
Transmission Electron ◽  
The Matrix ◽  
Movement Ability ◽  
Tan Δ ◽  
Oligomeric Silsesquioxane

In this work, a series of heptaphenyl siloxane trisilanol/polyhedral oligomeric silsesquioxane (T7-POSS) modified by polyols with different molecular weights were synthesized into liquid-like nanoparticle–organic hybrid materials using the grafted-from method. All grafted POSS nanoparticles changed from solid powders to liquid at room temperature. Polyurethane (PU) nanocomposites with POSS contents ranging from 1.75 to 9.72 wt % were prepared from these liquefied polyols-terminated POSS with polyepichlorohydrin (POSS–PECH). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the morphology of the POSS–PECH/PU nanocomposites. The results showed that the polyol-terminated POSS particles overcame the nanoagglomeration effect and evenly disperse in the polymeric matrix. The damping factor (tan δ) of resultant nanocomposites increased from 0.90 to 1.16, while the glass transition temperature decreased from 15.8 to 9.4 °C when POSS contents increased from 0 to 9.75 wt %. The gel content, tensile strength and Fourier transform infrared (FTIR) analyses demonstrated that the molecular thermal movement ability of the polyurethane (PU) matrix increased with increasing POSS hybrid content. Therefore, the improvement of the damping properties of the composites was mainly due to the friction-related losses occurring in the interface region between the nanoparticles and the matrix.

Synthesis and Characterization of Chitosan-Silver Nanocomposite Film

2016 ◽  
Vol 11 ◽  
pp. 22-29 ◽  
Author(s):  
Olayinka J. Olaniyan ◽  
Enock O. Dare ◽  
Olayide Rasaq Adetunji ◽  
Omolola O. Adedeji ◽  
Shephrah O. Ogungbesan
Keyword(s):  
Nanocomposite Film ◽  
Low Cost ◽  
Scale Up ◽  
Packaging Material ◽  
Uniform Size ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Resonance Band ◽  
Silver Nanocomposite ◽  
Uv Visible

Chitosan is termed as one of the useful carbohydrate oligosaccharides derived from chitin, which can be used to improve film packaging by hybridizing with silver due to their advantages of flexibility, easy scale up and low cost methods. Design of packaging material with non-toxic property becomes key issue. The objective of this work is to synthesize and characterize chitosan-silver nanocomposite film for effective packaging. The nanocomposite was synthesized using in-situ, co-mixing chemical method and air drying method. The morphology integrity of the nanohybrid was confirmed using UV-Visible Spectrophotometer, Transmission Electron Microscope (TEM) and X-ray Diffraction (XRD). TEM analysis revealed the cap shaped spherical morphology with no agglomeration and uniform size distribution of the nanoparticles within the range of 20.00 nm. UV-visible analysis showed Plasmon resonance band at 275 nm and 435 nm indicating the presence of chitosan and silver with no observable peak and an increase in intensity of chitozan. XRD confirmed the order and crystalline peak located at 2θ = 35ᵒ, 64ᵒ and 77ᵒwhich have been keenly indexed as face centred cubic Silver nanocrystals.Thus, the nanocomposite film produced serves as an effective packaging material.

scholarly journals Silica-Polystyrene Nanocomposite Particles Synthesized by Nitroxide-Mediated Polymerization and Their Encapsulation through Miniemulsion Polymerization

2006 ◽  
Vol 2006 ◽  
pp. 1-10 ◽  
Author(s):  
Bérangère Bailly ◽  
Anne-Carole Donnenwirth ◽  
Christèle Bartholome ◽  
Emmanuel Beyou ◽  
Elodie Bourgeat-Lami
Keyword(s):  
Silica Nanoparticles ◽  
Functional Group ◽  
Silica Surface ◽  
Miniemulsion Polymerization ◽  
Molecular Weights ◽  
Transmission Electron ◽  
Shell Particles ◽  
Terminal Functional Group ◽  
Nitroxide Mediated Polymerization

Polystyrene (PS) chains with molecular weights comprised between 8000 and 64000g⋅mol-1and narrow polydispersities were grown from the surface of silica nanoparticles (Aerosil A200 fumed silica and Stöber silica, resp.) through nitroxide-mediated polymerization (NMP). Alkoxyamine initiators based on N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (DEPN) and carrying a terminal functional group have been synthesized in situ and grafted to the silica surface. The resulting grafted alkoxyamines have been employed to initiate the growth of polystyrene chains from the inorganic surface. The maximum grafting density of the surface-tethered PS chains was estimated and seemed to be limited by initiator confinement at the interface. Then, the PS-grafted Stöber silica nanoparticles were entrapped inside latex particles via miniemulsion polymerization. Transmission electron microscopy indicated the successful formation of silica-polystyrene core-shell particles.

Sign in / Sign up

Export Citation Format

Share Document