Papers by Keyword: Polyvinyl Pyrrolidone

Abstract: Transdermal patches find extensive application in both medicine and cosmetics, offering distinct functional properties based on their unique formulations. In this study, polymer film patches were developed using a mixture design methodology, incorporating polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), glycerol (GLY), and deionized water (DW). To investigate the impact of the mixture on patch viscosity, seventeen different mixtures were designed using extreme vertices and were prepared through a simple casting technique. The special quartic model proved to be the most suitable for explaining the relationship between ingredients and predicting viscosity, as it demonstrated impressive statistical performance with a standard deviation of 296.237, an R-squared value of 99.80%, and a mean absolute percentage error of 4.24%. To validate the accuracy of our viscosity predictions, five mixture ratios were randomly selected from the contour plots, resulting in a mean absolute percentage error of 7.71%. In evaluating viscosity and mixture ratio, PVA demonstrated a significant influence compared to other constituents. Higher levels of PVP correlated with increased viscosity, whereas increased GLY concentration led to decreased viscosity. Additionally, the impact of GLY on viscosity diminishes with higher concentrations of PVP and PVA, aligning with the antagonistic terms PVP*GLY and PVA*GLY. Furthermore, antagonistic behavior was observed for the PVA*DW interactions, while synergistic tendencies were observed for the PVA*PVP interaction.

Abstract: In this work, titanium dioxide (TiO₂) ceramic nanofiber was prepared by homemade electrospinning technique. A homogeneous solution of titanium isopropoxide in polyvinyl pyrrolidone (PVP) was prepared. The thermal behavior of the fiber was characterized by differential thermal analyzer (DTA) and thermogravimetric analysis (TGA) to obtain the calcination temperature range. Fourier transform infrared spectroscopy (FTIR) was employed to analyze the chemical structures of the TiO₂/PVP composite nanofibers. The structural phase formations were characterized by x-ray diffraction technique (XRD). It has been found that the single phase of anatase and rutile were obtained at the calcinations temperature at 500 and 900 °C, respectively. The microstructure was characterized by a scanning electron microscope technique (SEM). The diameter of titanium oxide nanofibers were in the range of 70 nm to 300 nm and decrease as the calcination temperature increasing. The results indicated the effect of calcination temperature on the crystalline phase and morphology of the nanofiber.

Abstract: The effect of polyvinyl pyrrolidone (K30) and nickel acetylacetonate (Ni (acac)₂) on the fabrication of polyacrylonitrile (PAN) fiber was investigated. K30 and Ni (acac)₂ were chosen as pore-forming agents to prepare mesoporous carbon fibers.Meanwhile, the concentration of K30 and Ni (acac)₂, the mass ratio of pore-forming agent to PAN, the rheological properties of spinning dope, the mechanical properties, thermal performance of fiber precursor were also characterized. Furthermore, the precursor fibers and the carbon fibers were researched by FTIR analysis, TG analysis and static benzene adsorption. Based on the research, when the concentration of K30 and Ni (acac)₂ was 5%, the mass ratio of K30/Ni (acac)₂ to PAN was 7:3, the fiber precursors had excellent properties. Adding poreforming agent, the pore distribution was controlled.

Abstract: The Avrami equation was used in the study of the isothermal crystallization kinetics of Polyvinyl pyrrolidone/Polyamide 6 Blends. The addition of PVP can hinder the PA6 crystallization process, increase the crystallization half-time and make the crystallization rate decrease. The molecular entanglements and intermolecular hydrogen bonds between PA6 and PVP chains exert some influence also.

Abstract: 3-10％(wt) Polyvinyl pyrrolidone (PVP) was mixed with PA6 through the twin-screw extruder, a new type of high hygroscopic nylon resins can be obtained. With the increasing addition of PVP the crystalline state of PA6 changes from γ to α phase. The intermolecular hydrogen bond exists between PVP and PA6. The FTIR and WAXD analysis can approve the existence of the intermolecular hydrogen bond and the change of the PA6 crystalline state.

Abstract: Nanosized silver (Ag) was synthesized by reducing high concentration AgNO3 in N, N-dimethylformamide (DMF), in the presence of stabilizer polyvinyl pyrrolidone (PVP). PVP of two different molecular weights (MW=40000, 1300000) at the reaction temperature of 80°C and 100°C were tested for the effect on the formation of diverse silver nanoparticles. Our results indicated that the PVP with different molecular weights plays different role in the controlling of the Ag nanostructure owing to the PVP molecular selective adsorption on different crystal facets, thus affecting the growth rate of different facets of Ag nanoparticles. When all the other conditions kept the same and the temperature of 100°C, if PVP (Mw=40,000) was used, only a small amount of Ag decahedra were found. However, when the PVP with larger molecular weight such as PVP K88 (Mw=1300, 000), a large quantity of the triangular nanoprisms existed in the final solution in spite of the minority of quasi-sphere. The growth process and causation of different silver morphology with two distinct PVP have been briefly discussed.

Abstract: The ultrafine fibers of poly(ε-caprolactone) (PCL) composited with different Polyvinyl Pyrrolidone (PVP) content were successfully prepared by electrospinning method. The morphology, hydrophilicity and in vitro degradation behavior of samples were characterized by Scanning Electron Microscopy (SEM), water contact angle and weight loss rate. Pore size and distribution on the fibers changed with the increase of PVP content. The hydrophilicity of PCL membrane was improved by addition of PVP. When the content of PVP was 25% and 50%, the water contact angle approached zero. The degradation was essentially a dissolution process of PVP on the first 7days. Since large specific surface, high porosity and different crystallinity, percent degradation loss of electrospun fiber membranes were about 1 to 12 times higher than that of cast films.

Abstract: Ba(Zn_0.3Co_0.7)₂Fe₁₆O₂₇ hexagonal ferrites have been prepared by sol-gel method. Effects of polyvinyl pyrrolidone (PVP) on crystalline phase, natural surface and electromagnetic properties were analyzed. The XRD patterns of samples with and without PVP added both showed the single phase of hexagonal ferrite. The particle thickness increased when PVP was added. Moreover, Ferrites prepared with 2.0g PVP added into the sol solution had lower complex permittivity. Addition of PVP can be an effective way to obtain the electromagnetic match of hexagonal ferrites.