Preparation and characterization of graphene oxide/PMMA nanocomposites with amino-terminated vinyl polydimethylsiloxane phase interfaces

2016 ◽  
Vol 36 (9) ◽  
pp. 867-875 ◽  
Author(s):  
Hongyan Li ◽  
Weian Wang ◽  
Lin Cheng ◽  
Jing Li ◽  
Yajing Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Bending Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Amidation Reaction

Abstract Graphene oxide (GO) was prepared by the Hummers method and was grafted by an amino-terminated vinyl polydimethylsiloxane (AP). The AP-modified GO (GO-AP) was incorporated in poly(methylmethacrylate) (PMMA) to prepare nanocomposites. Raman microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis were used to characterize the particles. The mechanical properties, thermal stability, thermal conductivity, and dispersing status of the PMMA-based nanocomposites were also investigated. The results indicated that AP was grafted on the surface of GO via the amidation reaction, and the quantity of the grafted AP was approximately 20 wt% that of GO-AP. With the addition of GO-AP, the three-point bending strength of GO-AP/PMMA increased to approximately 58 MPa, and the dispersion of the particles was also enhanced. GO wrapped by AP could not form thermal conducting networks at the percolation thresholds. The increasing amount of AP prevented the formation of thermal conduction network and decreased the thermal conductivity of the composites. The thermal stability of the composites was affected by three main reasons, and the total effect of the three reasons on thermal stability illustrated a negative trend.

Preparation and Characterization of Polysiloxane Modified Graphene Oxide/PMMA Nanocomposites with Non-Convalent Interfaces

2017 ◽  
Vol 48 ◽  
pp. 191-203 ◽  
Author(s):  
Hong Yan Li ◽  
Li Meng Song ◽  
Ru Yi Li ◽  
Cong Sun ◽  
Yong Qiang Fu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Bending Strength ◽  
Bulk Polymerization ◽  
X Ray ◽  
Covalent Interaction ◽  
Three Point Bending ◽  
Modified Graphene Oxide

Graphene oxide (GO) was modified by polyphenylvinylsiloxane (PPVS) through π-π conjugation interaction. The modified GO/PMMA nanocomposites were prepared via in situ bulk polymerization. The modification of GO was characterized by using Fourier transformed infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Thermal conductivity, thermal stability and mechanical properties of PMMA and its composites were investigated by using TG, heat conduction analysis, and three-point bending strength test, respectively. The results showed that PPVS modified GO was prepared through non-covalent interaction, and composites with non-convalent phase interfaces were also obtained. With the addition of GO-PPVS, the three-point bending strength of GO-PPVS/PMMA increased to about 68 MPa. GO wrapped by PPVS could not form thermal conducting networks at the percolation thresholds. The increasing amount of PPVS prevented the formation of thermal conduction network, and decreased the thermal conductivity of the composites. The thermal stability of the composites was influenced by three main factors, and the total effect of the three factors on thermal stability illustrated a negative trend.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

scholarly journals Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Xinchuan Fan ◽  
Yue Hu ◽  
Yijun Zhang ◽  
Jiachen Lu ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

Pd/SiO2 Organic-Inorganic Hybrid Materials by Sol-Gel Method: Preparation and Thermal Stability under H2 Atmosphere

2015 ◽  
Vol 1118 ◽  
pp. 20-27
Author(s):  
Jing Yang ◽  
Bao Song Li ◽  
Xiang Huo ◽  
Hao Xu ◽  
Hai Yun Hou
Keyword(s):  
Thermal Stability ◽  
Calcination Temperature ◽  
Hybrid Materials ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Good Thermal Stability ◽  
Pd Doping

Pd/SiO2 organic-inorganic hybrid materials were prepared by adding PdCl2 into methyl-modified silica sol. The Pd/SiO2 hybrid materials were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of calcination temperature and Pd-doping on the phase transition of Pd element and the thermal stability of CH3 group in the Pd/SiO2 organic-inorganic hybrid materials were investigated. The results showed that the reduced metallic Pd0 exhibits good thermal stability under H2 atmosphere in the calcination process. Pd element in noncalcined Pd/SiO2 materials exists in PdCl2 form, calcination at 200 °C in a H2 atmosphere produces some metallic Pd0 and calcinations at 350 °C results in the complete transformation of Pd2+ to metallic Pd0. With the increase of calcination temperature, the Pd0 particle sizes increase and the hydrophobic Si−CH3 bands decrease in intensity. As the calcination temperature is greater than or equal to 350 °C, the loading of metallic Pd0 nearly has no influence on the chemical structure but, with the increase of Pd content, the formed Pd0 particle size increases. To keep the hydrophobicity of Pd/SiO2 membrane materials, the optimal calcination temperature is about 350 °C under H2 atmosphere.

scholarly journals Synthesis and Characterization of a New Aluminum-Doped Bismuth Subcarbonate

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 466
Author(s):  
Loisangela Álvarez ◽  
Blanca Rojas de Gascue ◽  
Rolando J. Tremont ◽  
Edgar Márquez ◽  
Euclides J. Velazco
Keyword(s):  
Infrared Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Energy Dispersive ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Characterization Methods ◽  
X Ray ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Anionic Part

A new compound, Bi2O2CO3:Al, was synthesized by the coprecipitation method. The characterization was done by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), electronic scanning microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The characterization methods allowed to identify the Bi2O2CO3:Al compound, such as the Al-doped Bi2O2CO3 by XRD, the anionic part (CO32−) by FTIR, and the presence of aluminum in the compound by XPS and EDX. It was confirmed to have a nanostructure like a nanosheet and a microstructure that resembles a type sponge by SEM.

scholarly journals Degradation of acetamiprid using graphene-oxide-based metal (Mn and Ni) ferrites as Fenton-like photocatalysts

2020 ◽  
Vol 81 (1) ◽  
pp. 178-189 ◽  
Author(s):  
Asma Tabasum ◽  
Ijaz Ahmad Bhatti ◽  
Nimra Nadeem ◽  
Muhammad Zahid ◽  
Zulfiqar Ahmad Rehan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Advanced Oxidation Process ◽  
Irradiation Time ◽  
Wastewater Remediation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimization Study ◽  
Excellent Activity ◽  
Oxide Composites

Abstract This study aims to explore the photocatalytic potential of graphene-oxide-based metal ferrites for the degradation of acetamiprid (an odorless neonicotinoid pesticide). Metal (Mn and Ni) ferrites (along with their graphene oxide composites) were prepared by the hydrothermal method while graphene oxide (GO) was synthesized using a modified Hummer's method. The composites were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The photocatalysts were studied for their Fenton-like advanced oxidation process to degrade acetamiprid. The composites showed excellent activity against acetamiprid degradation (>90%) in 60 min under UV irradiation. The detailed optimization study was carried out to investigate the influential variables (such as pH, catalyst dose, pollutant concentration, irradiation time, oxidant dose, etc.) to achieve enhanced degradation efficiency. Moreover, the findings were endorsed by central composite design (CCD). It was concluded that degradation was enhanced in an appropriate combination of photocatalyst and hydrogen peroxide. The magnetic character of the metal ferrites and their composites played an important role in the easy separation and reusability of these materials. The present findings result in highly effective, easy to handle and stable heterogeneous photo-Fenton materials for wastewater remediation.

Preparation and Properties of Spark Plasma Sintered AlN/BN Nano-Composites

2007 ◽  
Vol 352 ◽  
pp. 197-200
Author(s):  
Mei Juan Li ◽  
Lian Meng Zhang ◽  
Z.D. Wei ◽  
Qiang Shen ◽  
Dong Ming Zhang
Keyword(s):  
Thermal Conductivity ◽  
Chemical Process ◽  
Bending Strength ◽  
Nano Composites ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

Nano-sized turbostritic-BN (t-BN) was fabricated through chemical process using boric acid and urea in this work. By the same method, the AlN powders coated with nano-BN were prepared too. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) revealed that nano-sized t-BN was synthesized at about 600°C in nitrogen gas and it surrounded the surface of AlN particles. High-density AlN/BN nano-composites were fabricated spark plasma sintering (SPS). Microstructure and properties of AlN/BN nano-composites (5~30vol% BN) were investigated. The h-BN flake particles were homogenously dispersed at AlN grain boundaries and within grains in the AlN/BN composites. A little nano-BN additions significantly improved the bending strength of the nano-composites. However, the bending strength was decreased with the BN content increasing. The thermal conductivity of AlN/BN nano-composites was investigated too.

Pd/SiO2 Inorganic–Organic Composite Membrane Calcined Under N2 Atmosphere: Thermal Stability and H2/CO2 Separation

2019 ◽  
Vol 19 (6) ◽  
pp. 3210-3217
Author(s):  
Jing Yang ◽  
Wang-Qing Fan ◽  
Ruihua Mu ◽  
Yamei Zhao
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Total Pore Volume ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
N2 Atmosphere ◽  
Bet Specific Surface Area ◽  
The Mean

A novel Pd/SiO2 inorganic–organic composite material was developed for the selective separation of H2 from a mixture of H2 and CO2. Its thermal stability and microstructure calcined under N2 atmosphere were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N2 sorption–desorption measurements. Pd element in Pd/SiO2 gel material exists in PdCl2 form, calcination at 350 °C can result in the complete transformation of Pd2+ to metallic Pd0. With the increase of calcination temperature, the hydrophobic Si–CH3 bands decreased in intensity. The residue of Pd/SiO2 material calcined at 800 °C was mainly composed of Si–O–Si, metallic Pd0, CSi4 and some elemental C0. The mean pore size, BET specific surface area and total pore volume of the as-prepared Pd/SiO2 material calcined at 350 °C was about 2.26 nm, 417.35 m2 g−1 and 0.288 m3 g−1, respectively. The mean H2 and CO2 permeances of the corresponding Pd/SiO2 membrane were 9.90×10−6 and 9.10×10−7 mol m−2 Pa−1 s−1, respectively, when operating at 200 °C and a pressure difference of 0.3 MPa. After the steam exposure at 200 °C for 168 h, the H2 permeance decreased by 3.23% while the H2/CO2 permselectivity increased by 2.50%.

Microstructure and Mechanical Property of Ti3AlC2/TiAl3 Composite Synthesized by Hot Pressing

2015 ◽  
Vol 816 ◽  
pp. 210-215
Author(s):  
Wei Ping Chen ◽  
Yong Zeng ◽  
Xiao Mei Li ◽  
Hua Qiang Xiao
Keyword(s):  
Hot Pressing ◽  
Bending Strength ◽  
Milling Process ◽  
Toughening Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
New Phase ◽  
Microstructure And Mechanical Property

Ti3AlC2/TiAl3 composite was successfully fabricated by ball milling and in-situ reaction/hot-pressing of Ti, Al and graphite powders mixture at 1200 °C and 30 MPa for 30 min. The phase composition and microstructure of the milled powders and synthesized composite were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the mechanical properties and the toughening mechanism of 20%vol Ti3AlC2/TiAl3 composite was also studied. The results show that no new phase is detected during 50 h of milling process. The in-situ synthesized samples are fully dense and composed of 72%vol TiAl3, 24%vol Ti3AlC2 and 4%vol Al2O3/TiC. The Vickers Hardness, three-point bending strength and fracture toughness of the composite is ~5.2 GPa, ~243 MPa and ~4.3 MPa/m1/2, respectively. Analysis of microstructure reveals that crack deflection, crack bridging and delamination of Ti3AlC2 are the main mechanism responsible for the toughening.

A Mild and Efficient Approach for the Reduction of Graphene Oxide

2013 ◽  
Vol 652-654 ◽  
pp. 206-209
Author(s):  
Yu Feng Wang ◽  
Chun Hua Han ◽  
Bao Liu ◽  
Dong Mei Zhao ◽  
Dong Yu Zhao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Efficient Approach ◽  
Low Toxicity

A mild and efficient approach for the reduction of graphene oxide by NaHTe is reported in this work. This reductant is of low toxicity and nonvolatile and it reduce GO to graphene at room temperature in 2h. X-ray diffraction results showed that NaHTe can reduce GO completely in shorter time, comparing with hydroxylamine. Furthermore, X-ray photoelectron spectroscopy also indicates the reduction of GO to grapheme.

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