scholarly journals Structural Analysis of Polyhedral Oligomeric Silsesquioxane Coated SiC Nanoparticles and Their Applications in Thermoset Polymers

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Md. Reza-E-Rabby ◽  
Shaik Jeelani ◽  
Vijaya K. Rangari
Keyword(s):  
Photoelectron Spectroscopy ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Mechanical And Thermal Properties ◽  
Tem Analysis ◽  
Sic Nanoparticles ◽  
X Ray ◽  
Thermoset Resin ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Oligomeric Silsesquioxane

The SiC nanoparticles (NPs) were sonochemically coated with OctaIsobutyl (OI) polyhedral oligomeric silsesquioxane (POSS) to create a compatible interface between particle and thermoset polymer. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to analyze the structure of OI-POSS coated SiC nanoparticles. These results revealed the formation of a covalent bonding between SiC and OI-POSS. The transmission electron microscopy (TEM) analysis of OI-POSS coated SiC nanoparticles has also shown the indication of attachment between these two nanoparticles. The OI-POSS coated SiC nanoparticles were further reinforced into a thermoset resin system in order to evaluate mechanical and thermal properties of nanocomposites. The flexural strength, modulus, and glass transition temperature were found to be enhanced while SiC and OI-POSS coated SiC were infused into epoxy system compared to those properties of neat epoxy resin.

scholarly journals Surface Study of CuO Nanopetals by Advanced Nanocharacterization Techniques with Enhanced Optical and Catalytic Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1298 ◽  
Author(s):  
Muhammad Arif Khan ◽  
Nafarizal Nayan ◽  
Shadiullah Shadiullah ◽  
Mohd Khairul Ahmad ◽  
Chin Fhong Soon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Average Length ◽  
Tem Analysis ◽  
X Ray ◽  
Surface Study ◽  
Transmission Electron ◽  
One Step ◽  
Controlled Morphology ◽  
Xrd Patterns

In the present work, a facile one-step hydrothermal synthesis of well-defined stabilized CuO nanopetals and its surface study by advanced nanocharacterization techniques for enhanced optical and catalytic properties has been investigated. Characterization by Transmission electron microscopy (TEM) analysis confirmed existence of high crystalline CuO nanopetals with average length and diameter of 1611.96 nm and 650.50 nm, respectively. The nanopetals are monodispersed with a large surface area, controlled morphology, and demonstrate the nanocrystalline nature with a monoclinic structure. The phase purity of the as-synthesized sample was confirmed by Raman spectroscopy and X-ray diffraction (XRD) patterns. A significantly wide absorption up to 800 nm and increased band gap were observed in CuO nanopetals. The valance band (VB) and conduction band (CB) positions at CuO surface are measured to be of +0.7 and −1.03 eV, respectively, using X-ray photoelectron spectroscopy (XPS), which would be very promising for efficient catalytic properties. Furthermore, the obtained CuO nanopetals in the presence of hydrogen peroxide ( H 2 O 2 ) achieved excellent catalytic activities for degradation of methylene blue (MB) under dark, with degradation rate > 99% after 90 min, which is significantly higher than reported in the literature. The enhanced catalytic activity was referred to the controlled morphology of monodispersed CuO nanopetals, co-operative role of H 2 O 2 and energy band structure. This work contributes to a new approach for extensive application opportunities in environmental improvement.

scholarly journals Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 195
Author(s):  
Snežana S. S. Nenadović ◽  
Ljiljana M. Kljajević ◽  
Marija M. Ivanović ◽  
Miljana M. Mirković ◽  
Nadežda Radmilović ◽  
...  
Keyword(s):  
Rare Earth ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Alkali Activation ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Na Ions

The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides.

scholarly journals Enhanced Mechanical and Thermal Properties of Stereolithography 3D Printed Structures by the Effects of Incorporated Controllably Annealed Anatase TiO2 Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
Suhail Mubarak ◽  
Duraisami Dhamodharan ◽  
Nidhin Divakaran ◽  
Manoj B. Kale ◽  
T. Senthil ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Anatase Phase ◽  
Low Energy ◽  
Mechanical And Thermal Properties ◽  
Tem Analysis ◽  
X Ray ◽  
Energy Bandgap ◽  
3D Printed

Fabrication of low-cost, durable and efficient metal oxide nanocomposites were successfully synthesized and reinforced with photo-resin via 3-dimensional printing. Here, we put forward a novel approach to enhance the mechanical and thermal behaviors of stereolithography (SLA) 3D printed architecture by adding TiO2 nanoparticles (TNPs) in different crystalline phases (anatase and rutile), which were obtained at different annealing temperatures from 400 °C to 1000°C. The heat-treated anatase TNPs were scrutinized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, diffusive reflectance spectroscopy (DRS), and transmission electron microscopy (TEM) analysis. Among all the samples, at 800 °C, annealed anatase TNPs exposed a highly crystalline anatase phase, having a low energy bandgap and a comparably high tensile strength (47.43 MPa) and high elastic modulus (2.261 GPa) for the 3D printed samples, showing improvement by 103% and 32%, respectively, compared with the printed pristine stereolithography resin (SLR) sample. Moreover, enhanced storage modulus and tan δ values were achieved via the better interfacial interactions between the incorporated nanofillers and the SLR matrix. In addition to this, enhanced thermal conductivity and thermal stability of the SLR matrix were also noted. The low energy bandgap and nanoscale size of the fillers helped to achieve good dispersion and allowed the UV light to penetrate at a maximum depth through the photo resin.

scholarly journals A novel polyhedral oligomeric silsesquioxane-modified layered double hydroxide: preparation, characterization and properties

2018 ◽  
Vol 9 ◽  
pp. 3053-3068 ◽  
Author(s):  
Xianwei Zhang ◽  
Zhongzhu Ma ◽  
Hong Fan ◽  
Carla Bittencourt ◽  
Jintao Wan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Release ◽  
Layered Double Hydroxide ◽  
Photoelectron Spectroscopy ◽  
Degradation Kinetics ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Step Method ◽  
X Ray ◽  
Double Hydroxide ◽  
Oligomeric Silsesquioxane

A novel layered double hydroxide modified by octa-substituted carboxy-terminated polyhedral oligomeric silsesquioxane was prepared via a one-step method and characterized by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, elemental analysis, thermogravimetric analysis, and microscale combustion calorimetry (MCC). Results showed that the silsesquioxane modified-LDH (OLDH) revealed an increase in the interlayer distance, nanoscale plate-like morphology of primary particles, and improved thermal stability. A synergistic effect between the siloxane moiety and Mg–Al hydroxide was found during thermal degradation, and confirmed by the study of degradation kinetics together with the analysis of the surface morphologies and elemental components of char residues. Moreover, in contrast to conventional organic modified LDH (e.g., dodecylbenzenesulfonate-LDH), the MCC results showed a significant decrease in the heat release rate and total heat release, indicating the low flammability of OLDH.

Effect of Atomic Oxygen Exposure on Polyhedral Oligomeric Silsesquioxane/Polyimide Hybrid Materials in Low Earth Orbit Environment

2011 ◽  
Vol 492 ◽  
pp. 521-524 ◽  
Author(s):  
Shu Wang Duo ◽  
Mi Mi Song ◽  
Ting Zhi Liu ◽  
Chang Yuan Hu ◽  
Mei Shuan Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atomic Oxygen ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Surface Region ◽  
Low Earth Orbit ◽  
Hybrid Films ◽  
Sem Images ◽  
Near Surface ◽  
X Ray ◽  
Oligomeric Silsesquioxane

A novel polyimide (PI) hybrid nanocomposite containing polyhedral oligomeric silsesquioxane (POSS) had been prepared by copolymerization of octa(aminophenyl)silsesquioxane (OAP-POSS), 4,4’ -oxydianiline (ODA), and pyromellitic dianhydride (PMDA). The AO resistance of these POSS/PI hybrid films was tested in the ground-based AO simulation facility. Exposed and unexposed surfaces have been characterized by X-ray photoelectron spectroscopy and FTIR. The XPS data indicate that the carbon content of the near-surface region is decreased from 63.6 to 19.3 at% after AO exposure. The oxygen and silicon concentrations in the near-surface region increase after AO exposure. The data reveal the formation of a passive inorganic SiO2 layer on the POSS/PI hybrid films during the AO exposure, which serves as a protective barrier preventing further degradation of the underlying polymer with increased exposure to the AO flux. SEM images showed that the surface of the 10 wt% POSS/PI became much less rough than that of the pristine polyimide. The AO resistance of the POSS/PI hybrid films is up to several tenfold than that of the pristine polyimide.

Preparation of TiB2/TiN Nanocomposites by SP

2013 ◽  
Vol 745-746 ◽  
pp. 551-554 ◽  
Author(s):  
Ming Hui Wang ◽  
Hua Jian Li ◽  
Wan Jiang
Keyword(s):  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Spark Plasma ◽  
Xrd Techniques

TiB2/TiN nanocomposites were in-situ fabricated by spark plasma sintering (SPS) technique using Ti and BN powders as starting materials. The phase constituents and microstructures of the samples were analyzed by X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. The results showed that the average grain size of TiB2 and TiN was 1m and 300nm respectively. Furthermore, high resolution TEM analysis indicated that the as-prepared TiB2/TiN nanocomposites had very clean grain boundaries, and no amorphous phase or oxide layer was observed.

Microstructure, electrical properties, and thermal stability of Ti-based ohmic contacts to n-GaN

1999 ◽  
Vol 14 (3) ◽  
pp. 1032-1038 ◽  
Author(s):  
L. L. Smith ◽  
R. F. Davis ◽  
R-J. Liu ◽  
M. J. Kim ◽  
R. W. Carpenter
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Tem Analysis ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Specific Contact ◽  
Contact Resistivities ◽  
Thermal Stability Of

Single Ti layers, single TiN layers, and thin Ti films overlayered with Au were investigated as ohmic contacts to n-type (n 4.5 × 1017 to 7.4 × 1018 cm−3) single-crystal GaN (0001) films. Transmission line measurements (TLM) revealed the as-deposited TiN and Au/Ti contacts on n = 1.2 − 1018 cm−3 to be ohmic with room-temperature specific contact resistivities of 650 and 2.5 × 107minus;5 Ω cm2, respectively. Single Ti layer contacts had high resistance and were weakly rectifying in the as-deposited condition. The three contact/GaN systems exhibited a substantial decrease in resistivity after annealing; the value of ρc was also a function of the carrier concentration in the GaN. The Au/Ti contacts exhibited the lowest resistivity values yet observed in these contact studies, particularly for the more lightly doped n-GaN. The ρc for n = 1.2 × 1018 cm−3 reached 1.2 × 1026 Ω cm2; for n = 4.5 × 1017 cm−3, ρc = 7.5 × 1025 Ω cm2 after annealing both samples through 900 °C. X-ray photoelectron spectroscopy (XPS) and high-resolution cross-sectional transmission electron microscopy (X-TEM) analysis revealed the formation of TiN at the interface of annealed Ti layers in contact with GaN, which is believed to be beneficial for ohmic contact performance on n-GaN.

Carbon Nanotubes Grafted with Hyperbranched Triazine Compounds

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550012 ◽  
Author(s):  
Tingting Li ◽  
Hongxia Yan ◽  
Tianye Liu ◽  
Chao Liu ◽  
Zhengyan Chen
Keyword(s):  
Carbon Nanotubes ◽  
Fourier Transform ◽  
Photoelectron Spectroscopy ◽  
Condensation Reaction ◽  
Resin Matrix ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Electron Microscopes

In order to improve the dispersibility of carbon nanotubes (CNTs) in the resin matrix, CNTs grafted with hyperbranched triazine compound (HPTC–CNTs) was produced by four generations condensation reaction using cyanuric chloride and hexamethylenediamine. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV-Vis spectroscopy (UV-Vis) and transmission electron microscopes (TEM) were used to characterize the obtained HPTC–CNTs. The FTIR, XPS, UV-Vis and TEM analysis showed that CNTs had been successfully grafted with HPTC. The TGA showed that the content of HPTC on the surface of CNTs was about 58 wt.%. And the HPTC–CNTs had good dispersion both in water and acetone.

scholarly journals α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 581
Author(s):  
Gajanan S. Ghodake ◽  
Surendra K. Shinde ◽  
Ganesh D. Saratale ◽  
Rijuta G. Saratale ◽  
Min Kim ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Photoelectron Spectroscopy ◽  
Cellulose Fibers ◽  
Relative Activity ◽  
Significant Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Laccase Immobilization ◽  
Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

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