scholarly journals Polyethylene/Clay Nanocomposites Produced byIn SituPolymerization with Zirconocene/MAO Catalyst

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Pimpatima Panupakorn ◽  
Ekrachan Chaichana ◽  
Piyasan Praserthdam ◽  
Bunjerd Jongsomjit
Keyword(s):  
Catalytic Activity ◽  
Clay Nanocomposites ◽  
Gravimetric Analysis ◽  
Amine Group ◽  
Linear Low Density Polyethylene ◽  
X Ray ◽  
Polymerization System ◽  
Crystallite Sizes ◽  
Group A

Two commercial nanoclays were used here as catalytic fillers for production of polyethylene (PE) and linear low-density polyethylene (LLDPE) nanocomposites viain situpolymerization with zirconocene/MAO catalyst. It was found that both types of nanoclays designated as clay A and clay B can improve thermal stability to the host polymers as observed from a thermal gravimetric analysis (TGA). The distribution of the clays inside the polymer matrices appeared good due to thein situpolymerization system into which the clays were introduced during the polymer forming reaction. Upon investigating the clays by X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR), it was observed that the crucial differences between the two clays are the crystallite sizes (A < B) and the amounts of amine group (A < B). The higher amount of amine group in clay B was supposed to be a major reason for the lower catalytic activity of the polymerization systems compared to clay A resulting from its deactivating effect on zirconocene catalyst. However, for both clays, increasing their contents in the polymerization systems reduced the catalytic activity due to the higher steric hindrance occurring.

On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

2014 ◽  
Vol 3 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Hannes Alex ◽  
Norbert Steinfeldt ◽  
Klaus Jähnisch ◽  
Matthias Bauer ◽  
Sandra Hübner
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Aerobic Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Oxidation Of Benzyl Alcohol ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

scholarly journals A Facile Method to Construct MXene/CuO Nanocomposite with Enhanced Catalytic Activity of CuO on Thermal Decomposition of Ammonium Perchlorate

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Ammonium Perchlorate ◽  
Photoelectron Spectra ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Improved Performance ◽  
Calcination Method

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.

Magnetic Pd/Fe3O4 Composite: Synthesis, Structure, and Catalytic Activity

2014 ◽  
Vol 67 (10) ◽  
pp. 1387 ◽  
Author(s):  
Shi-Qiang Bai ◽  
Lu Jiang ◽  
Sheng-Li Huang ◽  
Ming Lin ◽  
Shuang-Yuan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Reduction Process ◽  
Pd Nanoparticles ◽  
Pincer Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Transmission Electron

Composite Pd/Fe3O4 (1) was designed and synthesised by immobilization of tridentate pincer ligands with triethoxysilane groups on Fe3O4 nanoparticles, PdII complexation, and in-situ reduction process. The composite was characterised by transmission electron microscopy, scanning electron microscopy energy-dispersive X-ray spectroscopy, powder X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analysis. The composite featured Pd nanoparticles of ~2–4 nm, exhibited good thermal stability and hydrophilic property as well as excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in water.

Effect of calcination temperature on properties of waste alkaline battery-based catalysts for deep oxidation of toluene and o-xylene

2020 ◽  
pp. 0958305X2093255
Author(s):  
Young-Kwon Park ◽  
Min Ki Kim ◽  
Sang Chul Jung ◽  
Wang Geun Shim ◽  
Seong Ho Jang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Space Velocity ◽  
Deep Oxidation ◽  
Bet Surface Area ◽  
Gravimetric Analysis ◽  
Average Pore ◽  
X Ray ◽  
Alkaline Battery

To evaluate waste alkaline battery (WB) as a catalyst for deep oxidation of toluene and o-xylene, we investigated how calcination temperature influenced the catalytic activity of WB-based catalyst for catalyst preparation. Physicochemical properties of WB-based catalysts were characterized by BET (Brunauer Emmett Teller) analysis, XRD (X-ray diffraction), SEM/EDX (scanning electron microscope/energy dispersive X-ray), TGA/DTA (thermo gravimetric analysis/differential thermal analysis), and H2-TPR (hydrogen temperature programmed reduction). Major elements of WB-based catalysts were carbon, manganese, zinc, and iron. The catalytic activity of WB-based catalyst was significantly influenced by calcination temperatures ranging from 300 °C–600°C. An increase calcination temperature resulted in a significant decrease in the BET surface area and concentrations of surface carbon and chlorine of the WB-based catalyst, while levels of other components increased. The average pore diameter of the WB-based catalyst calcined at 400 °C (WB (400) catalyst) was the smallest. The concentrations of manganese and iron in WB (400) catalyst were the highest, while those of manganese and iron in the WB-based catalyst calcined at 300 °C (WB (300) catalyst) were the lowest. Therefore, a good performance of WB (400) catalyst was likely due to its higher concentrations of manganese and iron and smaller pore size. When GHSV (gas hourly space velocity) was 40,000 h−1, toluene and o-xylene were completely oxidized on WB (400) catalyst at 430 °C and 440 °C, respectively.

Synthesis and Electrorheological Characteristics of Conducting Polymer/Clay Nanocomposites

2007 ◽  
Vol 124-126 ◽  
pp. 1083-1086
Author(s):  
Jun Hee Sung ◽  
Hyoung Jin Choi
Keyword(s):  
Conducting Polymer ◽  
Electrorheological Fluid ◽  
Clay Nanocomposites ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Internal Structures ◽  
In Situ Emulsion Polymerization

Nanocomposites of conducting polymers of polyaniline (PANI), poly(oethoxyaniline) (PEOA) and polypyrrole (PPy) with clay prepared via either in-situ emulsion polymerization or solvent intercalation were investigated especially for electrorheological fluid (ER) application. Internal structures of these nanocomposites were examined via wide angle X-ray diffraction (WAXD), and transmission electron microscope (TEM). The intercalated nanostructures analyzed via WAXD and TEM were correlated with the electrical property change originated from the nanoscale interaction between clay and conducting polymer. Moreover, their ER behaviors were measured via rotational rheometer with external electric field controller.

Modification of clays with styrenic ionic liquid by Synthesis of in-situ Polystyrene Nanocomposite

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammad Galehassadi ◽  
Fatemeh Hosseinzadeh ◽  
Mehrdad Mahkam
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Insitu Polymerization ◽  
Thermal Stability Of

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.

Study on the Preparation and Properties of EVA-G-PU/OMMT Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 247-250
Author(s):  
Yu Qing Zhang ◽  
Yu Xin He ◽  
Li Zhang ◽  
Jun Xian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Clay Nanocomposites ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
Thermal Stabilities ◽  
X Ray ◽  
Transmission Electron ◽  
New Type

A new type of EVA-g-PU/OMMT nanocomposites was synthesized through the method of chemical modification and melt intercalation. FTIR testing showed that the PU prepolymer was grafted on EVA main chains successfully. The structures of EVA-g-PU/OMMT nanocomposites were characterized by X-ray diffraction (XRD) and by high-resolution transmission electron microscopy (HRTEM). The enhanced storage modulus of EVA-g-PU/OMMT nanocomposites was characterized by dynamic mechanical analysis (DMA). The thermal stabilities of EVA/clay nanocomposites were also studied by thermal gravimetric analysis (TGA). Mechanical testing showed that the tensile strength and tear strength of EVA-g-PU/OMMT nanocomposites were far superior to pure EVA.

scholarly journals High Dielectric Constant Study of TiO2-Polypyrrole Composites with Low Contents of Filler Prepared byIn SituPolymerization

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Khalil Ahmed ◽  
Farah Kanwal ◽  
Shahid M. Ramay ◽  
Asif Mahmood ◽  
Shahid Atiq ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Filler Content ◽  
Aqueous Dispersion ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Crystalline Nature ◽  
High Dielectric ◽  
Thermal Stability Of

TiO2/polypyrrole composites with high dielectric constant have been synthesized byin situpolymerization of pyrrole in an aqueous dispersion of low concentration of TiO2, in the presence of small amount of HCl. Structural, optical, surface morphological, and thermal properties of the composites were investigated by X-ray diffractometer, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and thermogravimetric analysis, respectively. The data obtained from diffractometer and thermal gravimetric analysis confirmed the crystalline nature and thermal stability of the prepared composites. The dielectric constant of 5 wt% TiO2increased with filler content up to 4.3 × 103at 1 kHz and then decreased to 1.25 × 103at 10 kHz.

scholarly journals An in situ XAS study of the activation of precursor-dependent Pd nanoparticles

2018 ◽  
Vol 20 (18) ◽  
pp. 12700-12709 ◽  
Author(s):  
Christian W. Lopes ◽  
Jose L. Cerrillo ◽  
Antonio E. Palomares ◽  
Fernando Rey ◽  
Giovanni Agostini
Keyword(s):  
Catalytic Activity ◽  
Absorption Spectroscopy ◽  
Pd Nanoparticles ◽  
X Ray ◽  
In Situ Xas ◽  
Inorganic Supports ◽  
X Ray Absorption

The activation of precursor-dependent Pd nanoparticles was comprehensively followed by in situ X-ray absorption spectroscopy on two inorganic supports for rationalizing the final catalytic activity.

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