scholarly journals Surface Modification of Fumed Silica by Plasma Polymerization of Acetylene for PP/POE Blends Dielectric Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1957 ◽  
Author(s):  
Xiaozhen He ◽  
Ilkka Rytöluoto ◽  
Rafal Anyszka ◽  
Amirhossein Mahtabani ◽  
Eetta Saarimäki ◽  
...  
Keyword(s):  
Surface Modification ◽  
Photoelectron Spectroscopy ◽  
Plasma Polymerization ◽  
Silica Surface ◽  
Plasma Reactor ◽  
Charge Trapping ◽  
Plasma Modification ◽  
Modified Silica ◽  
Depolarization Current ◽  
X Ray

Novel nanocomposites for dielectric applications-based polypropylene/poly(ethylene-co-octene) (PP/POE) blends filled with nano silica are developed in the framework of the European ‘GRIDABLE’ project. A tailor-made low-pressure-plasma reactor was applied in this study for an organic surface modification of silica. Acetylene gas was used as the monomer for plasma polymerization in order to deposit a hydrocarbon layer onto the silica surface. The aim of this modification is to increase the compatibility between silica and the PP/POE blends matrix in order to improve the dispersion of the filler in the polymer matrix and to suppress the space charge accumulation by altering the charge trapping properties of these silica/PP/POE blends composites. The conditions for the deposition of the acetylene plasma-polymer onto the silica surface were optimized by analyzing the modification in terms of weight loss by thermogravimetry (TGA). X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray fluorescence spectroscopy (EDX) measurements confirmed the presence of hydrocarbon compounds on the silica surface after plasma modification. The acetylene plasma modified silica with the highest deposition level was selected to be incorporated into the PP/POE blends matrix. X-ray diffraction (XRD) showed that there is no new crystal phase formation in the PP/POE blends nanocomposites after addition of the acetylene plasma modified silica. Differential scanning calorimetry results (DSC) show two melting peaks and two crystallization peaks of the PP/POE blends nanocomposites corresponding to the PP and POE domains. The improved dispersion of the silica after acetylene plasma modification in the PP/POE blends matrix was shown by means of SEM–EDX mapping. Thermally stimulated depolarization current (TSDC) measurements confirm that addition of the acetylene plasma modified silica affects the charge trapping density and decreases the amount of injected charges into PP/POE blends nanocomposites. This work shows that acetylene plasma modification of the silica surface is a promising route to tune charge trapping properties of PP/POE blend-based nanocomposites.

scholarly journals Surface Modification of Fumed Silica by Dry Silanization for PP/POE-based Dielectric Nanocomposites

2019 ◽  
pp. 32-36
Author(s):  
Xiaozhen He ◽  
Ilkka Rytöluoto ◽  
Amirhossein Mahtabani ◽  
Eetta Saarimäki ◽  
Kari Lahti ◽  
...  
Keyword(s):  
Surface Modification ◽  
Dielectric Properties ◽  
High Voltage ◽  
Silica Surface ◽  
Trap Depth ◽  
Charge Trapping ◽  
Depolarization Current ◽  
Dry Process ◽  
Green Approach ◽  
Silica Surface Modification

A systematic study of the influence of surface modification of nanosilica with coupling agents having different polarities on the dielectric properties of a PP/POE/silica blend was performed. The main goal of this investigation was to tailor the chemical composition of the silica surface, in order to modify the charge trapping properties of the nanocomposites. For the modification of the silica surface, a “green” approach was utilized: a dry silanization method, which is performed without the need of a solvent. The results of the thermogravimetric analysis (TGA) indicate that the dry process is an effective method to perform silica surface modification using alkoxysilanes.The charge trapping properties were studied by Thermally Stimulated Depolarization Current (TSDC) measurements. The obtained TSDC results show significant differences in charge trapping properties of PP/POE composites filled with differently modified silicas. Polar functional groups attached to the surface of the silica appear to have a strong effect on the charge trapping properties: The trap depth distribution becomes deeper and the trap density decreases to significantly lower levels.All results show that incorporation of surface modified nanosilica into a PP/POE matrix is a promising approach to tailor its dielectric properties. Further development of these composites may lead to benefits for application in high-voltage cable and capacitor applications.Keywords: silica surface modification, dry silanization, charge trapping, PP, POE, TSDC, high voltage cable.

scholarly journals Amino-Modified Silica as Effective Support of the Palladium Catalyst for 4-Nitroaniline Hydrogenation

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 375
Author(s):  
Adele R. Latypova ◽  
Maxim D. Lebedev ◽  
Evgeniy V. Rumyantsev ◽  
Dmitry V. Filippov ◽  
Olga V. Lefedova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Electron Donor ◽  
Photoelectron Spectroscopy ◽  
Functionalized Silica ◽  
Amino Groups ◽  
Modified Silica ◽  
Pulse Technique ◽  
X Ray ◽  
Transmission Electron

The article describes the synthesis of aminoorgano-functionalized silica as a prospective material for catalysis application. The amino groups have electron donor properties which are valuable for the metal chemical state of palladium. Therefore, the presence of electron donor groups is important for increasing catalysts’ stability. The research is devoted to the investigation of silica amino-modified support influence on the activity and stability of palladium species in 4-nitroaniline hydrogenation process. A series of catalysts with different supports such as SiO2, SiO2-C3H6-NH2 (amino-functionalized silica), γ-Al2O3 and activated carbon were studied. The catalytic activity was studied in the hydrogenation of 4-nitroaniline to 1,4-phenylenediamine. The catalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and chemisorption of hydrogen by the pulse technique. The 5 wt.% Pd/SiO2-C3H6-NH2 catalyst exhibited the highest catalytic activity for 4-nitroaniline hydrogenation with 100% conversion and 99% selectivity with respect to 1,4-phenylenediamine.

Surface Modification of Acrylonitrile Fibers and Membrane by Nitrilase from Escherichia Coli BL21 (DE3)/pET-Nit

2011 ◽  
Vol 175-176 ◽  
pp. 651-655 ◽  
Author(s):  
Li Li Feng ◽  
Jian Fei Zhang ◽  
Hui Luo ◽  
Zheng Li
Keyword(s):  
Escherichia Coli ◽  
Surface Modification ◽  
Photoelectron Spectroscopy ◽  
Membrane Surface ◽  
Atomic Ratio ◽  
X Ray ◽  
Escherichia Coli Bl21 ◽  
Treated Fiber ◽  
Acrylic Fibers ◽  
Pan Fibers

The surface of polyacrylonitrile fibers and membrane were modified by nitrilase from Escherichia coli BL21 (DE3)/pET-Nit. Escherichia coli BL21(DE3)/pET-Nit was able to convert nitrile groups on PAN fibers and membrane to corresponding carboxylic acid as indicated by X-ray photoelectron spectroscopy (XPS). An increase of O/C atomic ratio on the fiber and membrane surface showed an increase in hydrophilicity and fabric-dyeing efficiency. Strength of treated fiber decreased by only 1.17%, because only surfacial nitrile groups of acrylic fibers were hydrolyzed by E.coli BL21(DE3)/pET-Nit.

Effect of Oxide Charge Trapping on X-ray Photoelectron Spectroscopy of HfO2/SiO2/Si Structures

2009 ◽  
Vol 48 (4) ◽  
pp. 041201 ◽  
Author(s):  
Yasuhiro Abe ◽  
Noriyuki Miyata ◽  
Eiji Ikenaga ◽  
Haruhiko Suzuki ◽  
Koji Kitamura ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Charge Trapping ◽  
Oxide Charge ◽  
X Ray

Synthesis and Characterization of New Bimetallic Pt,Ag/SBA-15 Materials

2013 ◽  
Vol 203-204 ◽  
pp. 81-85 ◽  
Author(s):  
Małgorzata Zienkiewicz-Strzałka ◽  
Marek Rotko ◽  
Stanislaw Pikus
Keyword(s):  
Photoelectron Spectroscopy ◽  
Silica Surface ◽  
Chemical Properties ◽  
Silver Ions ◽  
Nitrogen Adsorption ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
Chloride Complexes ◽  
X Ray

This paper reports, for the first time, synthesis and characterization of new bifunctional materials containing platinum and silver ions deposited on mesoporous ordered silica SBA-15. Both types of ions were incorporated on silica surface during adsorption from water solutions containing various amounts of dissolved tetraamineplatinum(II) dichloride and diamminesilver(I) hydroxide or tetraamineplatinum(II) dichloride and diamminesilver(I) chloride complexes. The silanol groups on silica surface play important role in adsorption mechanism and one of the most commonly used technique for their characterization is photoacoustic spectroscopy. This technique provides clear evidence of successfully incorporation two types of precious metal ions (Pt and Ag) on SBA-15 surface. The decomposition process of absorbed complexes was investigated according to high temperature in helium. The products of decomposition were analyzed by mass spectrometer. Obtained results show that decomposition temperature of platinum and silver complexes are quite vary. Similarly mechanisms of decomposition of ligands from silver and platinum complexes are also different. Moreover, the structural and chemical properties of Pt,Ag-SBA-15 samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS).

PREPARATION OF ULTRA-THIN CATION EXCHANGE COMPOSITE MEMBRANES BY A NOVEL PLASMA POLYMERIZATION TECHNIQUE

2007 ◽  
Vol 14 (06) ◽  
pp. 1165-1168 ◽  
Author(s):  
ZHONGQING JIANG ◽  
YUEDONG MENG ◽  
ZHONGJIE JIANG ◽  
YICAI SHI
Keyword(s):  
Photoelectron Spectroscopy ◽  
Plasma Polymerization ◽  
Composite Membranes ◽  
Proton Exchange ◽  
Uniform Structure ◽  
Scanning Electron Micrographs ◽  
Capacitively Coupled ◽  
X Ray ◽  
Monomer Structure ◽  
Ft Ir

An after-glow capacitively coupled discharge technique has been used to fabricate ultra-thin proton exchange composite membranes in a plasma polymerization reactor, where styrene and acrylic acid are used as starting materials. By this technique, a good preservation of monomer structure can be achieved. The structure and composition of the plasma polymerized membranes were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The morphology information and thickness of the membranes were provided by Scanning electron micrographs (SEM). The synthesized membranes are dense with uniform structure and rich with carboxyl acid groups. This novel plasma polymerization technique is expected to be used for the preparation of alternative membranes to preserve their monomer structure to a maximum extent.

A study of Al2O3:C films on Si(100) grown by low pressure MOCVD

2002 ◽  
Vol 747 ◽  
Author(s):  
M. P. Singh ◽  
C. S. Thakur ◽  
N. Bhat ◽  
S. A. Shivashankar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
High Frequency ◽  
Aluminium Oxide ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
X Ray ◽  
Transmission Electron ◽  
Current Voltage ◽  
Low Pressure Mocvd

ABSTRACTWe report the characterization of carbonaceous aluminium oxide, Al2O3:C, films grown on Si(100) by metalorganic chemical vapor deposition. The focus is on the study of the effects of carbon on the dielectric properties of aluminium oxide in a qualitative manner. The carbon present in the aluminium oxide film derives from aluminium acetylacetonate used as the source of aluminium. As-grown films comprise nanometer-sized grains of alumina (∼ 20–50 nm) in an amorphous carbonaceous matrix, as examined by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The films are shiny; they are smooth as observed by scanning electron microscopy (SEM). An attempt has been made to explore the defects (viz., oxide charge density) in the aluminium oxide films using room temperature high frequency capacitance – voltage (C-V) and current–voltage (I-V) measurements. The hysteresis and stretch-out in the high frequency C-V plots is indicative of charge trapping. The role of heteroatoms, as characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, in the transport of charge in Al2O3:C films is discussed.

Sign in / Sign up

Export Citation Format

Share Document