Papers by Keyword: PVP

Abstract: Nanofluid is well known as smart fluid which has high ability to recover oil. Therefore, it gains more significant effect in oil and gas industry. With the low concentration of nanofiller in nanofluid is used to enhance the numerous characteristics for oil recovery applications. Then, the main feature is the size of reinforcing agent and properties along matrix medium. Nano dimensional particles suspension in polymeric matrix have major advantages are stable sedimentation, optical, mechanical, electrical, and rheological properties that can be affected during the synthesis of nanofluids. Therefore nanoparticles/polymeric nanofluid have exceptional characteristics over the conventional fluid. Mixed nanoparticles/polymeric nanofluid in the presence of surfactant have effective interfacial tension and wettability which is evident for the development of nanofluids for oil recovery. In this context, the designed experimental study of silica/PVP nanofluids is synthesized via two step methods and characterized by SEM, TG/DTA, contact angle measurement, centrifugal effect and sedimentation test intended for Enhanced Oil Recovery (EOR) system.

Abstract: Octahedral Cu hierarchical nanostructures were prepared by electroless deposition in aqueous solution at 80 °C. Polyvinyl pyrrolidone (PVP) was employed as the protective and structure directing agent to prevent oxidation and agglomeration of the Cu products. Addition of higher amounts of PVP (about 1.275 g) resulted in smaller but irregularly-shaped Cu nanoparticles. The Cu nanoparticles have a mean particle diameter of about 200 nm with excellent size distribution. On the other hand, Cu octahedrals were produced when 0.425 to 0.850 g PVP was used. In situ mixed potential monitoring of the solution during electroless deposition revealed that the mixed potential was more positive at larger amounts of PVP. This can be attributed to slower reduction rate due to the decrease in the activity of Cu(II) ions. Consequently, smaller Cu nanoparticles were produced.

Abstract: A facile method has been developed to fabricate ZnO microstructures by a solution route at an 80°C. The microstructures with various morphologies were fabricated in water or anhydrous ethanol by using polyvinylpyrrolidone and cetyltrimethylammonium bromide as surfactants. ZnO rods with aspect ratios up to 30 have been created successfully in water through a hydrothermal process, while novel shuttle-like ZnO microstructures were fabricated in anhydrous ethanol using a similar procedure. ZnO rods revealed wurtzite-type crystal structure according to their X-ray diffraction (XRD) patterns. The morphologies of ZnO microstructures were adjusted conveniently by changing solvents and surfactants. In addition, the sizes of ZnO microstructures decreased under a long reaction time. This morphological evolution of ZnO microstructures indicated that the growth of ZnO is susceptive to reaction time due to the reaction between ZnO and aqueous ammonia. The facile strategy described here would be utilizable for the preparation of various metal oxide microstructures.

Abstract: A sample thermal treatment technique was utilised to synthesis cerium dioxide (CeO₂) nanoparticles, using cerium (111) nitrate as a precursor, Polyvinylpyrrolidone as a capping agent, and deionized water as a solvent. The product underwent calcination treatment of 500, 550, 600, and 650 1C to crystallize the nanoparticles and to remove organic compounds. It was verified by XRD that by varying the calcination temperature, the cubic fluorite structure of CeO₂ nanoparticles with pure products was achieved. Furthermore, the crystal sizes of the CeO₂ nanoparticles were assessed to be 4 nm for the lowest calcination temperature and 23 nm for the highest calcination temperature. The FESEM micrographs of the CeO₂ nanoparticles revealed a structure of CeO₂ nanospherical that exhibited a tendency to amalgamate at higher calcination temperatures. The optical characteristics that were evaluated with the help of a UV-Vis spectrophotometer indicated a decrease in the band gap energy with an increase in calcination temperature as a result of the increase in the crystal sizes.

Abstract: In this paper, Ag₂S nanomaterials with good morphology and crystalline have been prepared successfully by a hydrothermal method with AgNO₃ and (CH₂)₂CS as raw materials, SUDEI and PVP as surfactant, respectively. The photo-thermal transformation performance of the nanomaterials was studied. It was found that the Ag₂S nanomaterials had a good photo-thermal property and the corresponding photo-thermal transformation efficiency could reach up to 63%.

Abstract: Nanocomposite solid polymer electrolytes comprise of PMMA (poly methyl methacrylate), PVP (poly vinyl pyrolidone), MSA (methanesulfonic acid) and TiO₂ as nanofiller were prepared by solution casting technique at different compositions. Sample with 1 mol% incorporated TiO₂ has shown maximum conductivity and its value was found as 2.82 ×10^-5 S/cm. The value of conductivity has been enhanced to about 31% upon the addition of nanofiller. The relaxation time for all the prepared composites as well as for the composite having maximum conductivity at various isotherms have been calculated from the loss tangent plot. The frequency and temperature dependence of dielectric constant and dielectric loss nanocomposite solid polymer electrolytes have also been studied. The modulus analysis confirms the non-Debye type formalism in the prepared composites.

Abstract: This paper presents a new method to fabricate the porous nanofibrous mats by dual-nozzle electrospinning. Poly (vinyl alcohol) (PVA) and Poly (vinyl pyrrolidone) (PVP) were electrospun from two different syringes and mixed on the rotating drum to form PVA/PVP composite nanofibrous mats. SEM morphology indicated that the amount of collecting nanofibers reduced with decreasing the ratio of feeding rate between PVA and PVP. After dissolving in alcohol, the pore size of nanofibrous mats with feeding ratio of PVA/PVP at 4/1 was 1.352μm, which would be more beneficial for cells to migrate from pores.

Abstract: Hydrogen sulfide is a typical toxic, inflammable gas. The detection of H₂S is crucial in the areas of oil, natural gas and so on. However, studies on H₂S gas sensors at room temperature were seldom reported. In this study, Quartz crystal microbalance (QCM) sensors have been utilized, and PVP film were prepared on the QCM by airbrush method with different airbrush volume for H₂S detection. The results showed that the PVP film with airbrush volume 0.2ml exhibited a better sensing response to H₂S gas. Besides, sensitive characteristics parameters, i.e. selectivity, stability, linearity and sensitivity of prepared sensors were studied for comparison. The relative sensing mechanism associated with SEM pictures was studied as well.

Abstract: In this paper, multiple-walled carbon nanotubes (MWCNTs) monolayer film and MWCNTs-polyvinylpyrrolidone (PVP) composite films were fabricated on interdigitated electrodes (IDEs) by airbrush technology, respectively. Response performance of all the sensors to various concentrations of vapors including methanol, ethanol, acetone, tetrahydrofuran, water and 1,2-dichloroethane were investigated. The results showed that a larger sensing response was obtained for the composite films compared with the MWCNTs monolayer film. Moreover, the MWCNTs-PVP composite films had a good selectivity for 1,2-dichloroethane vapor.

Abstract: Polyvinylpyrrolidone (PVP)/boehmite nanocomposites fibers were successfully prepared by electrospinning using boehmite sol containing PVP as the spinning solution. Several techniques, including Fourier transform infrared (FT-IR), thermal gravimetric analyzer (TGA) and field emission scanning electron microscopy (FE-SEM) were used to characterize their ingredients, thermal properties and morphology. The results showed that PVP concentration exhibited significant effect on the PVP/boehmite nanofibers morphology. With increasing PVP concentration, the morphology changed from beaded, beaded fiber to uniform fiber. These PVP/boehmite nanofibers can be used as good candidates for continuously preparing uniform and compact alumina nanofibers.