scholarly journals Plasma Activation of Polyethylene Powder

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2099
Author(s):  
Hana Šourková ◽  
Petr Špatenka
Keyword(s):  
Oxygen Concentration ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Particle Diameter ◽  
Dust Particles ◽  
Average Particle ◽  
Experimental Conditions ◽  
Polyethylene Powder

Polyethylene powder of average particle diameter of 160 µm was activated in a plasma reactor made from aluminum of volume 64 dm3 at the pressure 100 Pa. Dense oxygen plasma was sustained with a microwave discharge powered by a pulsed magnetron source of power 1 kW mounted onto the top flange of the plasma reactor. Polymer powder was treated in a batch mode with 0.25 kg/batch. The powder was placed into a stainless-steel dish mounted in the center of the reactor where diffusing plasma of low ion density, and the O-atom density of 2 × 1021 m−3 was sustained. The powder was stirred in the dish at the rate of 40 rpm. The evolution of powder wettability versus treatment time was measured using the Washburne method, and the surface composition was determined by X-ray Photoelectron Spectroscopy (XPS). The wettability versus the oxygen concentration assumed a parabolic behavior. The maximal oxygen concentration, as revealed by XPS, was 17.5 at.%, and the maximal increase of wettability was 220%. The efficiency of O-atoms utilization in these experimental conditions was about 10% taking into account the spherical geometry of dust particles and perfectly smooth surface. The method is scalable to large industrial systems.

Plasma Treatment of Polymers for Improving Al Adhesion

1998 ◽  
Vol 544 ◽  
Author(s):  
R. Lamendola ◽  
E. Matarrese ◽  
M. Creatore ◽  
P. Favia ◽  
R. d'Agostino
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Treatment Time ◽  
Polymer Surface ◽  
Peel Test ◽  
Plasma Process ◽  
Metal Interface ◽  
Experimental Conditions ◽  
Polymer Metal

AbstractPET and Kapton thin films have been plasma processed in order to increase sputtered aluminum adhesion. The effect of different plasma feedings, such as NH3, O2, and He, has been evaluated on polymer/metal adhesion and on chemical modifications of polymer surface at different plasma power and treatment time. The chemistry at polymer/metal interface has been studied in order to find the suitable experimental conditions for transferring the plasma process to industrial scale.The role of acid-base reactions in promoting Polymer/Aluminum adhesion has been investigated. Surface composition has been investigated by X-ray Photoelectron Spectroscopy; adhesion measurements have been accomplished by 180° Peel Test.

scholarly journals Surface Modification of Polyamides by Gaseous Plasma—Review and Scientific Challenges

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3020
Author(s):  
Gregor Primc
Keyword(s):  
Surface Modification ◽  
Oxygen Concentration ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Prolonged Treatment ◽  
Water Contact ◽  
Static Water ◽  
Nitrogen Concentrations ◽  
Polar Functional Groups ◽  
Almost All

A review of the most significant scientific achievements in the field of surface modification of polyamides by non-equilibrium plasma treatments is presented. Most authors employed atmospheric pressure discharges and reported improved wettability. The super-hydrophilic surface finish was only achieved using a low-pressure plasma reactor and prolonged treatment time, enabling both the nanostructuring and functionalization with polar functional groups. The average increase of the oxygen concentration as probed by XPS was about 10 at%, while the changes in nitrogen concentrations were marginal in almost all cases. The final static water contact angle decreased with the increasing treatment time, and the oxygen concentration decreased with the increasing discharge power. The need for plasma characterization for the interpretation of experimental results is stressed.

Erosion of amorphous nickel-phosphorus

1987 ◽  
Vol 2 (6) ◽  
pp. 818-826 ◽  
Author(s):  
K. C. Goretta ◽  
J. L. Routbort ◽  
A. Mayer ◽  
R. B. Schwarz
Keyword(s):  
Material Removal ◽  
Erosion Rate ◽  
Shear Bands ◽  
Particle Diameter ◽  
Average Particle ◽  
Impingement Angle ◽  
Experimental Conditions ◽  
Erosion Rates ◽  
Alumina Particles ◽  
The Impact

The steady-state erosion rate of electrodeposited amorphous Ni80P20 by angular alumina particles has been measured as a function of impingement angle from 15°–90°, particle velocity from 50–100 m/s, and average particle diameter from 40–390 μm. The erosion rate can be described by a power law in velocity and particle size. The erosion rates in Ni80P20 were compared to those measured for electrodeposited pure crystalline nickel. For all experimental conditions the erosion rate in the amorphous alloy exceeded that of nickel. The material removal in amorphous Ni80P20 is attributed to formation of plastic shear bands below the impact areas. For the most energetic particles the erosion leads to the formation of melt, which seems to be a consequence of the localized shear.

Anti-Bacterial Property of Tussah Silk Fabric by Nano-Titanium Dioxide and Chitosan Modification

2011 ◽  
Vol 331 ◽  
pp. 330-333
Author(s):  
Yan Hua Lu ◽  
Zhi Mei Liu
Keyword(s):  
Titanium Dioxide ◽  
Photoelectron Spectroscopy ◽  
Particle Diameter ◽  
Nano Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Silk Fabric ◽  
Bacterial Reduction ◽  
Dispersion System ◽  
Nano Titanium Dioxide

In order to increase the anti-bacterail property of tussah silk fabric, a nano-material dispersion system contained titanium dioxide nano-particles, chitosan, 1,2,3,4-butane tetracarboxylic acid, sodium monophosphate and surfactants was prepared. The particles in the dispersion solution have a narrow particle size distribution with average particle diameter of approximately 40 nm. Tussah silk fabric was then modified with the dispersion system using a conventional pad-dry-cure method. The structure of the modified tussah silk was characterized by X-ray photoelectron spectroscopy (XPS). The anti-bacterial efficiency of the treated tussah silk fabric with the dispersion system at a concentration of 0.2% nano-titanium dioxide and 0.5% chitosan showed over 99% of bacterial reduction against the Staphylococcus aureus（S. aureus） and gram-negative bacterium Escherichia Coli (E. Coli). In addition, the anti-bacterial reduction was maintained over 90% even after being exposed to 20 consecutive launderings.

Silver electrochemical treatment of bamboo and its effect on decay fungi

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zehui Ju ◽  
Qian He ◽  
Tianyi Zhan ◽  
Haiyang Zhang ◽  
Lu Hong ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Average Particle Size ◽  
Silver Ions ◽  
Fungal Resistance ◽  
Phyllostachys Pubescens ◽  
Average Particle ◽  
Silver Plate ◽  
Decay Fungi

AbstractIn this study, a simple and effective method for preparing bamboo with high fungal resistance was first proposed. Flattened moso bamboo (Phyllostachys pubescens), which is a perishable species, was connected to a silver plate and exposed to a high-voltage electrostatic field (HEVF). The method was based on HEVF excitation of a silver plate to produce silver ions and facilitate in situ impregnation of bamboo. Silver ions were present in the forms of Ag(0), Ag(I) and Ag(III) and reacted with bamboo functional groups under HVEF treatment. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis showed that compared to those of untreated bamboo, the O/C ratio and OH content of treated bamboo were lower, the number of CHO groups decreased, the number of CO groups increased, and silver interacted with the hemicellulose and lignin of bamboo. The concentration of silver ions increased with increasing treatment time and voltage. The silver ions were nanocrystalline, and the average particle size was 50 nm. The mass loss and moisture content of the treated bamboo decreased significantly after exposure to decay fungi. Therefore, in situ impregnation of silver with HVEF was a simple and effective method to improve the durability of bamboo materials.

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

CO2 Reduction to Propanol by Copper Foams: A Pre- and Post-Catalysis Study

2020 ◽  
Author(s):  
Jennifer A. Rudd ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin Bain ◽  
Sunyhik Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Carbon Capture ◽  
Surface Composition ◽  
Co2 Reduction ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Ex Situ ◽  
X Ray ◽  
Copper Electrodes

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher value products. Herein, we describe the use of porous copper electrodes to catalyze the reduction of carbon dioxide into higher value products such as ethylene, ethanol and, notably, propanol. For <i>n</i>-propanol production, faradaic efficiencies reach 4.93% at -0.83 V <i>vs</i> RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We have documented the performance of the catalyst in both pristine and urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute electrolysis, the cuboctahedra and dendrites have undergone structural rearrangement. Changes in the interaction of urea with the catalyst surface have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found that alterations in the morphology, crystallinity, and surface composition of the catalyst led to the deactivation of the copper foams.

Green Synthesis and Enhanced CO2 Capture Performance of Perfluorinated Cerium-Based Metal-Organic Frameworks with UiO-66 and MIL-140 Topology

2018 ◽  
Author(s):  
Roberto D’Amato ◽  
Anna Donnadio ◽  
Mariolino Carta ◽  
Claudio Sangregorio ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Organic Frameworks ◽  
Isosteric Heat ◽  
Experimental Conditions ◽  
Cerium Ammonium Nitrate ◽  
Ideal Adsorbed Solution Theory ◽  
Metal Organic ◽  
Adsorbed Solution ◽  
Better Than ◽  
The Ideal

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO<sub>2</sub> sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO<sub>2</sub> over N<sub>2</sub>: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO<sub>2 </sub>adsorption is in the range of 38-40 kJ mol<sup>-1</sup>, indicating a strong physisorptive character.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

scholarly journals High Voltage Electric Discharge for Recovery of Chlorogenic Acid from Tobacco Waste

2021 ◽  
Vol 13 (8) ◽  
pp. 4481
Author(s):  
Marija Banožić ◽  
Antun Jozinović ◽  
Jovana Grgić ◽  
Borislav Miličević ◽  
Stela Jokić
Keyword(s):  
Chlorogenic Acid ◽  
Process Parameters ◽  
Electric Discharge ◽  
High Voltage ◽  
Treatment Time ◽  
Strong Dependence ◽  
Extraction Procedure ◽  
Polynomial Equation ◽  
Experimental Conditions ◽  
Tobacco Waste

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on the content of chlorogenic acid. The content of chlorogenic acid ranged from 1.54 to 3.66 mg/100 g for scrap, from 1.90 to 2.97 mg/100 g for dust, and from 2.30 to 3.38 mg/100 g for midrib extract, showing a strong dependence on the applied process parameters. The temperature change and the change in pH and electrical conductivity of the extracts after high voltage discharge treatment were also observed. The studied process parameters showed a statistically significant effect on the chemical and physical properties of the extracts from tobacco waste as well as on the content of chlorogenic acid, indicating the potential of HVED assisted processes in the separation of chlorogenic acid from tobacco industry waste. Multiple regression analysis was used to fit the results for the chlorogenic acid to a second order polynomial equation and the optimum conditions were determined.

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