Papers by Keyword: Polyvinylpyrrolidone

Abstract: Recent interests in hybrid polymers for fuel cell applications have given rise to the exploration, modification, and application of various polymer ionomers. Polymer membranes doped with suitable fillers have improved fuel cell performance compared to the pristine polymers. In this study, three ionomers, PAN, PVP, and PVA were synthesised idividually and then functionalised with zirconium phosphate nanoparticles as membrane nanofillers. The nanofibers were synthesised using the sol-gel polymerisation method from their respective precursors dissolved in either water or DMF solution. This was followed by their subsequent fabrication through the incorporation of the zirconium phosphate nanoparticles, which were synthesised from their precursor salt using the precipitation method. Techniques such as SEM, FTIR, TGA, and XRD were employed to characterise the physiochemical properties of the synthesised polymers. In addition, the electrochemical properties of the synthesised polymers were evaluated using CV and EIS. The obtained results showed that conductive nanofibers were successfully synthesized. As the scan rates increased under cyclic voltammetry, the reduction peak for PVP voltammograms disappeared, and the PAN exhibited an irreversible redox system. It is also noticeable that when scan speeds increase, the oxidation peaks for PAN voltammograms shift to higher potentials. On the other hand, the TGA results indicated that these nanoparticles had excellent thermal stabilities, making them suitable for use in fuel cell membranes under tough conditions. Based on these findings, PAN, PVA, and PVP polymer materials can be used as filler (dopant) materials for fuel cell membranes.

Abstract: The preparation of apolymeric membrane by a chemical method was introduced for a Polymer Electrolyte Membrane (PEM) fuel cell. Cobalt oxide (Co₃O₅) was used in the coexistent of two polymers to speed up the reaction process and to obtain the best results. Different tests were implemented along the research to evaluate the new membrane such as X-ray, Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR). The new membrane shown an increment both in the current (I) and the volume of Hydrogen (H₂) at a constant voltage (V).

Abstract: Microencapsulation of drugs is used for a long time to improve their properties. It was carried out a comparative assessment of the physical and physicochemical methods of microencapsulation on the example of some drugs. The spray drying method was selected from the physical methods. Physicochemical method based on simple coacervation was implemented by changing the solvent. A study and comparison of the properties of the products were obtained by UV and IR spectroscopy, liquid chromatography, electron microscopy. It was carried out a comparative assessment of the release profile of the active substance from microcapsules obtained by various methods. Using the example of furacilin microcapsules has been shown an increase in the biological activity of substances encapsulated in water-soluble polymers. The particle size distribution was determined by analyzing their trajectories. The main advantages and disadvantages of the two investigated encapsulation methods are outlined.

Abstract: Hydrophilic amino acids as a new type hydrate inhibitor is a hot topic for scholars. In this paper, the influence of glycine and L-arginine, and their complexation with polyvinylpyrrolidone (PVP) on hydrate formation were clarified by tetrahydrofuran (THF) hydrate formation simulation experiments, and the intrinsic influence mechanism was revealed by many experimental methods. The results show that glycine has a strong inhibitory effect on water molecules because of its strong disturbance to water molecules, and the inhibitory effect is the best when the addition of glycine is 1.0 wt%. Due to the disturbance and binding of hydrophilic amino acids to water molecules, the effect of PVP on the semi-cage structure of water molecules as well as the adsorption and encapsulation of hydrate crystal particles, the combination of glycine and L-arginine and PVP has synergistic inhibitory effect on the formation of THF hydrate. When the total amount of hydrate inhibitor is 1.0 wt%, the synergistic inhibition ability of glycine and PVP is stronger. The results obtained in this paper provide an experimental and theoretical basis for the research and development of new hydrate inhibitors.

Abstract: Superparamagnetic iron oxide nanoparticles (SPION) were synthesized by one pot coprecipitation method at room temperature in the presence of Polyvinylpyrrolidone (PVP). X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Vibrating Sample Magnetometer (VSM) were used to analysis the physicochemical properties of PVP-SPION. The XRD patterns confirmed that the structure of as-synthesized sample is magnetite with cubic structure system. In TEM results, the image of PVP-SPION displayed that the size of particles was 14.05 nm with narrower size distribution and also the PVP played important role to minimize the agglomeration of SPION. Finally, the high saturation magnetization value of PVP-SPION (53.0 emu/g) indicate the as-synthesized sample has a great potential as a contrast agent for MRI.

Abstract: Hydrothermally grown hexagonal wurtzite ZnO microrods coated with polyvinylpyrrolidone (PVP) via an ex-situ method, was successfully synthesized without using complex procedure or experimental setup. FTIR results confirm the presence of different functional groups of PVP at the ZnO surface and the chemical interaction of ZnO with the C=O ligand of the PVP molecule. The presence of PVP molecules prevents the absorption of atmospheric CO₂ by the Zn²⁺ ions since PVP chemically interacts with ZnO by attaching to the exposed cations. The coating concentration doesn’t induce a frequency shift in the vibrations of the PVP functional groups. The ZnO microrods possess good optical quality as indicated by the high UV absorption and pronounced excitonic peak at room temperature, even after coating with higher PVP concentrations.

Abstract: Magnetic nanoparticles are devices able to optimize cancer treatments. In particular, magnetite nanoparticles are very effective in producing heat to cause lysis of tumor cells. However, in order that nanoparticles are internalized without causing damage to body they must be coated by biocompatible material. In this work, Fe₃O₄ nanoparticles were coated by a polymer blend: polyethylene glycol / polyvinylpyrrolidone. Some variations in mass ratio of polymer mixture were made. The effect of varying mass ratio in polymers was investigated. Samples were characterized by X-ray diffraction and Rietveld analysis. Moreover, hysteresis curves were analyzed. The results indicate good agreement between mass proportions used and physical and magnetic properties of nanocomposite.

Abstract: Nanofibers produced by electrospinning method have high porosity, large surface area, long size, and their dimensions are ranging from nanometers to micrometers. The synthesis process was straightforward, uncomplicated and it can be processed from various type of materials and the nanofibers can be used as drug release. The polymer matrix acts as a carrier of other materials that will be spun. The purpose of this study was to to prepare electrospun fiber mats and to incorporate extracts from the leaves of Anredera cordifolia (Ten.) Steenis plant (Binahong). Polyvinylpyrrolidone (PVP) was used as a carrier matrix. Binahong leaf extract was added to a solution of PVP. The solution was then electrospun using a single nozzle and drum collector system under condition of voltage 12.5 kV, nozzle collector distance of 12 cm, and flow rate 10 μl /minute. In this study, the composite of Binahong extract and PVP solution was succesfully made into nanofiber.

Abstract: A totally green biocomposite was prepared via melt blending technique by using polyhydroxybutyrate (PHB) as a matrix, clamshells powder (CaCO₃) as a reinforcing filler and polyvinylpyrrolidone (PVP) as a binder. PHB/CaCO₃ was fixed at 70:30 ratio and PVP weight content varied at 3, 5, 7 and 9 wt%. The properties of the biocomposite have been studied in term of mechanical properties and morphology. The results showed that incorporation of PVP increased the tensile modulus which remarkably demonstrated by the enhancement in stiffness of the biopolymer. While, elongation at break decreased in an opposite behavior. Surface morphology observation on the tensile fracture samples shows the presence of microvoids, due to binding effect of the PVP.

Abstract: Electrospinning is one of techniques used for nanofiber fabrication as drug delivery systems. Curcumin possesses challenging properties as it has low solubility and poor absorption. Incorporation of curcumin into nanofiber is expected to enhance solubility and absorption. In this study, curcumin loaded nanofiber for oral delivery has been developed. Nanofibers were synthesized from curcumin and Polyvinylpyrrolidone (PVP) with mass ratio of 1:10 using electrospinning method. Various PVP concentration from 5 to 10 % (w/v) were used. To further assess the variation in the physical characteristics of fiber, the influence of Polysorbate 20, a nonionic surfactant, was studied. Electrospinning of curcumin-PVP nanofiber with the addition of Polysorbate 20 yielded fiber with overall diameter of 350-400 nm. In the absence of Polysorbate 20, the diameter was higher i.e 540-660 nm. The highest diameter was observed in highest PVP concentration at 10% (w/v). Drug release study showed that more than 50% of curcumin has been released within 45 minutes in all formulas. Initial rapid release occurred in the formula containing Polysorbate 20. As a summary, the presence of Polysorbate 20 reduced the diameter of curcumin-loaded PVP nanofiber and enhanced the release of curcumin from the fiber.