Papers by Keyword: PEO

Abstract: The Mn_0.3Fe_2.7O₄/PEO/PMMA/AC nanocomposites were synthesized using co-precipitation and solid-state reaction methods. The Mn_0.3Fe_2.7O₄/PEO/PMMA/AC nanocomposites were success formed. This was confirmed by characterization using FTIR instrument. The Fe-O, C-O, and C-H₂ functional groups were the representation of Mn_0.3Fe_2.7O₄, PEO/PMMA, and AC respectively. Investigation of crystal structure was characterized using XRD instrument. According to X-Ray Diffraction analysis, the crystal size was 10.82 nanometers and the peak of AC was detected on 2θ around 24.85^o. In addition, the investigation of magnetic properties was characterized using VSM instrument. This result showed that the Mn_0.3Fe_2.7O₄/PEO/PMMA/AC nanocomposites behave as a superparamagnetic material with a saturation magnetization value was around 12.55 emu/gram.

Abstract: Recent studies of chitosan/polyethylene oxide (PEO) nanofibrous membranes have been developed for biomedical and filtration applications. However, they have predominantly utilized chitosan/PEO blend. The present work used the chitosan nanoparticles (CSNPs) adding to the PEO solution and made the CSNPs/PEO nanofiber membranes using the electrospinning method. This study investigated the morphology and tensile properties of the CSNPs/PEO membranes affecting by varying CSNPs concentrations (0, 0.5, and 1.0 wt.%) and PEO solvents (70 and 96% ethanol). The neat PEO membrane revealed a wrinkle-like structure on the membrane surface, but it gradually disappeared by CSNPs concentration. An increase in CSNPs concentration decreased the average fiber diameter and increased the tensile strength of the membrane. They demonstrated a similar pattern for PEO solvent with both ethanol concentrations. In summary, the addition of 1.0 wt.% CSNPs in PEO solution with 96% ethanol resulted in high strength of the CSNPs/PEO nanofiber membrane.

Abstract: Magnesium alloy has been widely investigated as a biodegradable implant material owing to its unique properties to degrade spontaneously in human body fluid without causing toxicity. However, the degradation rate needs to be controlled. An effective way to lower down the degradation rate of Mg alloy is by coating with plasma electrolytic oxidation (PEO) technique. In this research, the microstructure and mechanical hardness of the PEO film formed on AZ31 were investigated. The film was prepared under a constant current of 400 A/m² in the Na₃PO₄ solution at 30°C. The voltage-time curve showed an immediate increase of current during the first 25 s before reaching a steady-state voltage of 150 V. The spark discharge revealed as white micro discharges. The film formed for 3 min exhibited a high surface roughness with a large variety of thickness in the range of 1-20 µm. The film contained pores and cracks. The big pores with diameter size 10-20 µm were formed as a result of gas entrapment, while the small pores with a radius of 1-3 µm were associated with the discharge tunnel during the PEO process. The X-ray diffraction pattern indicated that the film composed of crystalline Mg₃(PO₄)₂.

Abstract: PEO/graphene composites were prepared by a simple and green method in presence of graphite oxide (GO) reduced by Vitamin C (VC) in aqueous. In this process, GO was dispersed well into PEO aqueous solution before reduction. Although the carbon content and hydrophobic properties of graphene sheets were increased during the reduction, the uncompleted reduction process could be detected and confirmed by FTIR and TGA. The residual oxygen containing groups on the surface of graphene sheets could improve the compatibility of PEO and graphene sheets in aqueous.

Abstract: Plasma electrolytic oxidation (PEO) is a technique employed to significantly enhance the corrosion and tribological properties of the materials by forming an oxide ceramic film on the surface of the material. In this investigation, ZM21 Mg alloy was subjected to PEO treatment in silicate and phosphate-based aqueous solutions of 5grams and 10 grams per liter concentrations. The oxide film was characterized using SEM, profilometer, thickness meter, and polarization test. Results showed that the oxide film obtained with 10g/L phosphate-based solution offers higher corrosion resistance than the oxide films formed with other solutions.

Abstract: Electrospinning has become the most popular nanofibers production technique that many scientists around the world were intrigued by. It is based on electrostatic forces stretching a polymer solution that undergoes bending instability and eventually results in number of fine nanoscaled filaments. The study reports of four processing parameters effect on electrospun polyethylene oxide (PEO) fibers diameter and pores area. Fibers diameter increase results from the increase of time, volume flow rate and tip to collector distance with a critical value of the first two parameters. The pores area showed both decrease and increase after a critical value of the electrical voltage at 19 kV, while the mean pores area decreased with the time increase. Irregular trends of increasing and decreasing trends of the means pores area were noticed with the change of the volume flow rate and tip to collector distance..

Abstract: Novel and highly effective polyethylene oxide (PEO) based composite electrolytes were prepared by combining the graphene nanoplatelets (GR) and multiwall carbon nanotubes (MWCNT) for the application as solid polymer electrolyte. MWCNT and GR were used as reinforcing filler and as electrical conductivity enhancement agent. Dispersions in N,N-dimethylformamide (DMF) of MWCNT and GR within the PEO matrix were prepared. DMF are featured by high electron-pair donor number and low hydrogen-bonding parameters, therefore DMF is considered a standard for liquid-phase exfoliation of MWCNT and GR. In our study, the MWCNT and GR solutions were tip sonicated using an ultrasonic processor, operated at 80% amplitude. A pulse-mode (cycle of 0.5 s) sonication was used because of the system relaxation role for the off phase, allowing a higher cavitation intensity and lower heat generation to be reached. Subsequent heat pressing was applied to obtain thin solid PEO composite electrolytes. Analyses of the experimental and theoretical density of prepared solid PEO composite electrolytes are calculated and discussed. GR and MWCNT functionalization effect on void content of polymer composites is evaluated. FTIR analysis was carried out to further investigate the effect of fillers content. The SEM results showed that surface of electrolyte film became rougher after the addition of MWCNT and GR. It is concluded, that the higher is filler fraction, the lower is void content and greater is composite density.

Abstract: The objective of this study is to investigate the effect of ionic liquid to PEO-NaCF₃SO₃ solid polymer electrolyte. Sodium ion conducting polymer electrolyte films consisting of Polyethylene oxide (PEO) as a polymer host, Sodium trifluoromethanesulfonate (NaCF₃SO₃) as doping salt and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMiTF) as ionic liquid has been prepared by solution cast technique. Different amounts (5, 10, 15, 20, 25 and 30 wt. %) of EMiTF will be added to the optimized polymer-salt composition to develop PEO - NaCF₃SO₃ – EMiTF polymer electrolyte. Difference Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) indicated that the crystalline degree and the weight loss % of the electrolyte decrease with increasing the wt. % of the EMiTF respectively. The ionic transference number was found in the value of 0.95 which suggests that ions are the charge carriers.

Abstract: The polymer electrolyte composed of poly (ethylene oxide) (PEO) and sodium iodide (NaI) as dopant salt was prepared by using solution casting method. Effect of temperature on the conductivity performance was studied by impedance spectroscopy in the temperature range of 303 to 343K. The linear variation of conductivity with temperature suggests the Arrhenius type thermally activated process. The effect of temperature on the conductivity is discussed on the basis of number, n, mobility, μ and diffusion coefficient, D of free ions. In this paper, n, μ and D were determined using impedance spectroscopy method.

Abstract: Films of starch/PEO blends were prepared via solution casting technique and their properties with different amount of ammonium nitrate, NH₄NO₃ were compared. The measurement of conductivity at room temperature were carried out using impedance spectroscopy. The highest conductivity calculated is found to be 2.81±0.46 x 10^-7Scm^-1 with addition of 35wt% NH₄NO_{3 .}