CO-sensing properties of undoped and doped tin oxide thin films prepared by electron beam evaporation

Undoped thin films of tin oxide and those doped with indium oxide and nickel oxides were deposited by electron beam evaporation. The effects of the film thickness and preparation conditions (films prepared with or without the presence of oxygen environment during deposition) on the optical and carbon monoxide sensing properties of the films were studied. The films were characterized using X-ray diffraction and X-ray photoelectron spectroscopy and optical spectroscopy techniques. All the films were found to be amorphous. It was found that the sensitivity of the films to CO increased with the thickness and the porosity of the films. It was found that their selectivity to CO gas relative to CO₂ and SO₂ gases could be improved upon doping the films with indium (or nickel) oxide.     

Structure,microstructure and optical properties of cerium oxide thin films prepared by electron beam evaporation assisted with ion beams

Cerium oxide thin films were prepared by combined electron beam evaporation and ion beam assisted deposition techniques (EBE–IBAD). Their crystallographic structures, microstructures, and optical properties were studied as a function of the substrate temperature (200 °C and 500 °C) and the dose of Ar⁺ or O₂⁺ ion assistance during growth. X-ray diffraction was used to estimate the crystallographic texture, grain size, microstrain and lattice constant. Sample microstructure was studied by scanning electron microscopy. Transmission UV–vis spectroscopy was employed to obtain optical information (band gap, density, and refractive index). All films showed a cubic CeO₂ structure with different preferential growth depending on the preparation conditions. The bombardment with Ar⁺ ions during film deposition proved to be very effective for changing the film structure, hindering columnar growth and producing smaller grain sizes and higher values of microstrain and lattice constant. Films grown at 200 °C and Ar⁺ ion assistance showed the highest density, the smallest grain size (～10 nm) and a high expansion of the lattice constant (up to ～1%). This expansion is related to the presence of Ce³⁺ at the grain boundaries. Ion assistance during the growth leads to films with higher values of refractive index and lower values of band gap.     

Growth of group III nitride films by pulsed electron beam deposition

We have grown group III nitride films on Al₂O₃ (0 0 0 1), 6H-SiC (0 0 0 1), and ZnO () substrates by pulsed electron beam deposition (PED) for the first time and investigated their characteristics. We found that c-plane AlN and GaN grow epitaxially on these substrates. It has been revealed that the growth of GaN on atomically flat 6H-SiC substrates starts with the three-dimensional mode and eventually changes into the two-dimensional mode. The GaN films exhibited strong near-band-edge emission in their room temperature photoluminescence spectra. We also found that the use of PED allows us to reduce the epitaxial growth temperature for GaN down to 200 °C.     

Structure and tribological properties of Cu–PU–PTFE composite coatings prepared by low‐energy electron beam dispersion with glow discharge

Polytetrafluoroethylene (PTFE) composite coatings doped copper acetate and polyurethane (PU) were prepared on rubber substrate by low‐energy electron beam dispersion technique. The effects of dopant and glow discharge treatment on the surface morphology, structure and tribological properties of the coatings were investigated. The results showed that Cu–PTFE composite coatings form uniform surface and dense column structure with spherical aggregations under glow discharge treatment. PU coating shows the large size of protuberance structure but PU–PTFE coating presents spherical structure. Both of the coatings become relative dense and smooth after discharge treatment, and Cu–PU–PTFE composite coatings possess a smoother surface and lower polar component of surface energy. Cu doping weakens the crystallinity and ordering degree of composite coatings, but glow discharge increases the ordering degree and branched structure of C―H groups. Friction experiment indicated that Cu fails to improve the wear resistance of PTFE coatings but glow discharge treatment can do it. Cu–PU–PTFE coatings after discharge treatment have the higher wear resistance and lower coefficient of friction. Copyright © 2016 John Wiley & Sons, Ltd.     

Modification of microstructures and physical properties of ultra high molecular weight polyethylene by electron beam irradiation

An ultra high molecular weight polyethylene was irradiated with the electron beam at dose levels ranging from 100 kGY to 1 MGy. The microstructures of the irradiated samples were characterized by FTIR, gel fraction measurement, DSC, and small‐ and wide‐angle X‐ray scattering. For the mechanical properties, a static tensile test and creep experiment were also performed. The crosslinking and the crystal morphology changes were the main microstructural changes to influence the mechanical properties. It was found that 250 kGy appeared to be the optimal dose level to induce crosslinks in the amorphous area and recrystalliztion in the crystal lamellae. At doses above 250 kGy, the electron beam penetrates into the crystal domains, resulting in crosslinks in the crystal domains and reduction in the crystal size and crystallinity. The static mechanical properties (modulus, strength) and the creep resistance were enhanced by the electron beam irradiation. The stiffness rather correlated with the degree of crosslinks while the strength with the crystal morphology. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3019–3029, 2005     

Graft polymerization of acrylamide onto LLDPE film by electron beam pre-irradiation in air and argon. II. Influence of mohr's salt

LLDPE film pre-irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025–2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre-irradiation dose was quite insensitive to a hundred-fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.     

Pilot plant for flue gas treatment with electron beam -start up and two stage irradiation tests

The pilot plant for flue gas treatment with electron beam has been built at Power Plant Kaweczyn, near Warsaw. The irradiation part of the pilot plant has been put in operation in 1991 whereas the complete installation including bag filter started to work in spring 1992. The starting tests consisted of studying the components reliability and influence of the two-stage irradiation process on efficiency of NO_x removal. The results have shown that the two- stage irradiation leads to remarkable energy savings and retains high NO_x removal. The mathematical models of the double and triple irradiation process are discussed.     

Improvement of municipal wastewaters by electron beam accelerator in Brazil

Radiation processing of municipal sewage and sludge has been considered not only for disinfection but also for solids and organic matter removal in Brazil. The improvement of irradiated systems were demonstrated by the elimination of indicator bacteria and by the reduction on the total bacteria count, on the chemical and biochemical oxygen demand from raw sewage and biologically treated effluents. The selected doses of radiation to be applied to sewage and sewage sludge are in the range of 3.0 to 4.0 kGy to sewage and 4.0 to 6.0 kGy to sewage sludge.     

Solid-State polymerization of the binary mixture of methacrylate and liquid-crystalline compound by electron beam

Solid-state polymerization of a binary mixture of nonliquid-crystalline monomer and liquidcrystalline compound was carried out using electron beam. The monomers were benzoic acid containing 4-[ω-(meth)acryloyloxyalkyloxy] benzoic acids, in which the alkylene spacer was ethylene, hexamethylene, or undecamethylene. The conversion yield of monomer to polymer to a large extent increased with increasing content of a liquid-crystalline compound with a terminal carboxylic group, such as 4-n-alkyloxybenzoic acid, while the addition of a liquid-crystalline compound without terminal carboxylic group did not affect polymerization of the monomer. Phase diagrams of the mixture of monomer and liquid-crystalline compound were examined using cross-polarizing microscopy and differential scanning calorimetry (DSC). All mixtures of monomer and 4-n-alkyloxybenzoic acid or liquid-crystalline compound without terminal carboxylic group showed liquid-crystallinity in a broad composition range. It was concluded that liquid-crystalline compounds with terminal carboxylic acid may form hydrogen bondings with methacrylate or acrylate monomer having terminal carboxylic acid which enhance polymerizability of the mixture. The stereoregularity of polymers determined by NMR depended on increasing irradiation dose and temperature rather than the content of the added liquid-crystalline 4-n-decanoxybenzoic acid.     

Improvements of physical and mechanical properties of electron beam irradiation—crosslinked EVA foams

In this work, ethylene–vinyl acetate (EVA) copolymer foams were prepared and crosslinked by using high‐energy electron beam (e‐beam) radiation (10 MeV). The effect of parameters such as irradiation dose, the contents of foaming agent, radiation activator, and radiation sensitizer on improvement of physical and mechanical properties of the EVA foamed samples were investigated. The foams were obtained through a four‐step process of melt mixing, forming, crosslinking, and foaming. During the melt mixing process EVA was compounded with different amounts of azodicarbonamide (ADCA) as a blowing agent, zinc oxide (ZnO) as a radiation activator, and trimethylol propane‐trimethacrylate (TMPTMA) as a radiation sensitizer. The samples were compression molded into flat sheets at low temperature (110°C) and were then radiation‐crosslinked by 20–80 kGy e‐beam. Finally, the crosslinked samples were converted to foams by a high temperature (210°C) compression molding process. The foamed samples were analyzed in terms of gel content, density, compression molding set, tensile properties, and micro‐structural features. It was found that an increase in absorbed radiation dosage increases crosslink density, elasticity, percentage recovery, tensile strength, and compression properties of the EVA foams. Due to the increased recovery the percentage of compression set was reduced. Similarly increasing the TMPTMA content in the formulation increased the crosslink density and the resulting mechanical properties. Contrary to these findings, addition of ADCA led to the formation of extra gases which in turn reduced the crosslink density, and resulted in the deterioration of the mechanical properties and hence an increase in the compression set. However, addition of ZnO and TMPTMA led to the formation of smaller and more uniform cell size with improved mechanical properties. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of electron beam irradiation on mechanical and thermal properties of waste polyamide copolymer blended with nitrile‐butadiene rubber

In the present study, the effect of electron beam irradiation on the morphological, thermal, and mechanical properties of waste polyamide copolymer (WPA‐66/6) blended with different contents of acrylonitrile butadiene rubber (NBR) were studied. The prepared blends were subjected to irradiation doses up to 150 kGy and the structural modifications were discussed; non‐irradiated blends were used as control. Mechanical properties, namely, tensile strength (TS), yield strength, elongation at break, and hardness, were followed up as functions of irradiation dose and degree of loading with rubber content. On the other hand, the influence of irradiation dose on the thermal parameters, melting temperature, heat of fusion, ΔH_m of the recycled PA copolymer, and its blend with NBR were also investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

电子束辐照与电化学还原联用技术——一种用于煤炭直接液化的新方法

对电子束辐照与电化学联用技术提高煤炭液化率的新型方法进行了研究。利用高能电子束对煤炭样品进行辐照,并通过四氢呋喃萃取出辐照后的可能产物并计算其提取率。实验结果发现,提取产率随着辐照剂量的增加而增加,并得到在氧气气氛下25 kGy的最佳辐照条件。辐照的样品进一步在氢氧化钠电解液中电化学还原液化,并采用元素分析法、傅里叶红外光谱法、阴极极化曲线法、核磁共振法和计时电流法等来检测辐照对煤炭电化学还原的影响。     

Acid-base, electron donating and catalytic properties of sulfated zirconia

The electron donating properties of sulfated zirconia were studied from the adsorption of electron acceptors of various electron affinity. The surface acidity and basicity of the oxides have also been determined by titration method using a set of Hammett indicators. The data have been correlated with the catalytic activity of the oxide towards esterification of acetic acid usingn-butanol, reduction of cyclohexanol in 2-propanol and oxidation of cyclohexanol with benzophenone.     

Cation-exchange fabric prepared by electron beam-induced graft copolymerization of binary monomer mixture

Applying the electron-beam preirradiation method in air the cation - exchange fabric (CEF) containing sulfonic acid (R-SO₃H) groups was prepared by graft copolymerization of sodium styrenesulfonate with acrylic acid onto non woven polypropylene fabric. The effect of reaction conditions on the grafting yield and reaction mechanism was examined. The ion-exchange properties towards Cu(II) and Co(II) ions of the CEF were investigated depending on the form of the CEF and a pH of the solution. It was found that the synthesized CEF contains both strong acid groups (R-SO₃H) and weak acid (R-COOH) groups in almost equal proportion. The utilization of the CEF in Na₊ form allows to make the best use of its ion-exchange capacity.     

Variation of mechanical and thermal properties of the thermoplastics reinforced with natural fibers by electron beam processing

With restrictions for environmental protection being strengthened, the thermoplastics reinforced with natural fibers (NFs) such as jute, kenaf, flax, etc., appeared as an automobile interior material instead of the chemical plastics. Regardless of many advantages, one shortcoming is the deformation after being formed in high temperature of about 200 °C, caused by the poor adhesion between the natural fibers and thermoplastics. Also, the energy saving in connection with car air-conditioning becomes very important. In this study, the thermal conductivity, tensile strength, and deformation of several kinds of thermoplastic composites composing of 50% polypropylene (PP) and 50% natural fiber irradiated by the electron beam (energy: 0.5 MeV, dose: 0–20 kGy) were measured. The length and thickness of PP and NF are 80±10 mm and 40–120 μm, respectively. The results show that the thermal conductivity and the tensile strength changed and became minimum when the dose of electron beam is 10 kGy, and the deformation after the thermal cycle were reduced by the electron beam.     

Remotion of organic compounds of actual industrial effluents by electron beam irradiation

Organic compounds has been a great problem of environmental pollution, the traditional methods are not effecient on removing these compounds and most of them are deposited to ambient and stay there for long time causing problems to the environment. Ionizing radiation has been used with success to destroy organic molecules. Actual industrial effluents were irradiated using IPEN's electron beam wastewater pilot plant to study organic compounds degradation. The samples were irradiated with and without air mixture by different doses. Irradiation treatment efficiency was evaluated by the Cromatography Gas Analyses of the samples before and after irradiation. The studied organic compounds were: phenol, chloroform, tetrachloroethylene (PCE), carbon tetrachloride, trichloroethylene (TCE), 1,1-dichloroethane, dichloromethane, benzene, toluene and xilene. A degradation superior to 80% was achieved for the majority of the compounds with air addition and 2kGy delivered dose condition. For the samples that were irradiated without air addition the degradation was higher.     

Measurements and calculations of absorbed dose in electron beam radiation processing

An electron beam current densimeter has been described and used for dose measurement in EB radiation processing. An improved bipartition model of electron transport is applied to calculate the reflection coefficients and energy deposition distributions produced by 0.2–3 MeV electrons in semi-infinite media of Al, C, MAR and nylon, and the energy deposition produced by 2 MeV electrons in the two-layer medium consisting of copper and polystyrene. In addition, the depth dose distribution of 300 keV electrons in Ti-air-nylon composite-layer has been evaluated. The calculation results are in good agreement with the measurement data.     

Growth feature of PTFE coatings on rubber substrate by low‐energy electron beam dispersion

Polytetrafluoroethylene (PTFE) coatings were prepared on Si and acrylonitrile‐butadiene rubber substrates by low‐energy electron beam dispersion. The effects of substrate nature, distance of target to substrate (d_ts) and coatings thickness on the surface morphology, structure, and tribological properties of the coatings were investigated. The results showed that substrate nature affects the shape and size distribution of surface conglomerations of PTFE coatings due to the interaction process of active dispersion particles with underlying polymer layer. Surface energy of PTFE coatings decreases first with the coatings thickness increases to 1.25 µm and then slowly increases with the thickness. Structure defects (pore, interstice, and so on) in the coatings increase with the thickness increases but reduce significantly with the d_ts increases. PTFE coating prepared at the d_ts of 20 cm had a higher intensity of the amorphous absorption bands. Friction experiment indicated that the destroyed area of the coatings in the friction region decreases with increases the coatings thickness but increases with the d_ts. The rubber modified by PTFE coatings with spherical structure possesses a higher stability in the friction process and a lower coefficient of friction. Copyright © 2015 John Wiley & Sons, Ltd.     

Removal of La(III) by amino-phosphonic acid functionalized polystyrene microspheres prepared via electron beam irradiation

A new aminophosphonic acid chelating resin was successfully prepared via electron beam irradiation grafting combined with chemical modification and used for the efficient removal of La(III). Firstly, glycidyl methacrylate (GMA) was grafted to polystyrene microspheres (PS) via electron beam co-radiation to obtain PS-PGMA microspheres, then followed by the amination with diethylenetriamine (DETA) to formed PS-PGMA-DETA (PGD) microspheres through nucleophilic substitution between amino and epoxy group, and finally PS-PGMA-DETA-PA (PGDP) microspheres was obtained by phosphorylation with phosphorous acid (PA). The obtained chelating resin absorbent was characterized by Fourier-transform infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), which demonstrated that the millimetric aminophosphonic acid chelating resin were successfully prepared with well-defined morphology and enhanced thermal stability. The X-ray photoelectron spectroscopy (XPS) characterization results confirmed a possible adsorption mechanism, which is mainly based on the chelation and coordination of N and O in PDGP with La(III) in the solution. A series of parameters were taken into account in the adsorption experiment, such as absorbed dose, GMA concentration, dosage of PGDP, pH, contact time, temperature, and the initial concentrations of La(III). The maximum adsorption capacity obtained from the research can be achieved 288.69 mg/g at 298.15 K, pH = 6. The kinetic sorption for for La(III) fitted the type 1 pseudo-second-order (R² = 0.9981), which revealed that the La(III) are chemisorbed on the surface of the PGDP. It was concluded that the La(III) adsorption conformed to the Freundlich equation, indicating a multilayer adsorption process. Thermodynamic data indicated that the La(III) uptake process was a spontaneous and endothermic. In addition, this research provided a new irradiation grafting method for rare earth ions removal.