Synthesis and Characterization of Poly(N-Vinyl-2-Pyrrolidone/Itaconic Acid) Hydrogel

With N-vinyl-2-pyrrolidone (NVP) and itaconic acid(IA), poly(N-vinyl-2-pyrrolidone/itaconic acid)[P(NVP/IA)] hydrogel was synthesized by free radical solution polymerization. The structure of this (P(NVP/IA)) was characterized by IR. Effects of concentration of itaconic acid, amount of cross-link agent, N,N′-methylene-bis-acrylamide, reaction temperature, and time on properties of swelling ratio(SR) of the hydrogel were investigated.The results show that the best swelling property of the hydrogel is obtained at 50 ℃ and 1.5 h. pH sensitivity increases as the concentration of itaconic acid in the hydrogel system increases. Swelling ratio of the hydrogel decreases as the amount of cross-link agent increases.

CARBONYLATION OF ALLYL HALIDES CATALYZED BY POLY(N-VINYL-2-PYRROLIDONE) ANCHORED PALLADIUM CATALYST UNDER ATMOSPHERIC PRESSURE

Carbonylation of allyl halides catalyzed by poly(N-vinyl-2-pyrro- lidone) anchored palladium catalyst affords β,r-butonic acid under atmo- spheric pressure and at room temperature.The activity and efficiency of the catalyst are much higher than those of the reported catalysts for this reaction.

DSC STUDY ON THE WATER-ABSORBING MECHANISM OF PLASMA POLYMERIZED N-VINYL-2-PYROROLIDONE

Water existing in water-absorbing plasma polymerized N-vinyl-2-pyrrolidone(PPNVP) include pure bulk water, freezable water and non-freezing, or bound, water. The C-N bond of N, N-disubstituted amides in PPNVP was considered as an active binding site for bound water.

Ultrasonic-assisted Synthesis of Fe Nanoparticles in the Presence of Poly（N-vinyl-2-pyrrolidone）

Zero-valent iron particles were prepared by wet reduction chemistry assisted with ultrasonic treatment. Such prepared particles have uniform size, exhibit crystalline structure and show strong pararnagnetic property. Their surface modification by coating poly（N-vinyl-2-pyrrolidone） （PVP） was investigated. The resulting Fe（0）-PVP particles were monodispersed and possessed enhancing magnetization saturation. Those synthesis conditions to control the particle size and distribution were exploited.

Uncovering gold nanoparticle synthesis using a microchip laser system through pulsed laser ablation in aqueous solution

The synthesis of gold nanoparticles(Au NPs)was carried out by utilising the pulsed laser ablation in liquids(PLAL)method with a microchip laser(MCL)system.This portable system features low power consumption and a giant-pulse laser.Aqueous solutions with and without the surfactant poly(N-vinyl-2-pyrrolidone)(PVP)were used for laser ablation of a bulk gold rod to achieve the successful formation of a colloidal solution of Au NPs.The gas bubbles formed by heating the aqueous medium around the surface of the gold target significantly reduced the efficiency of Au NP ablation.This effect was more pronounced and prolonged in high-viscosity solutions,hindering energy transfer from subsequent laser pulses to the target.Additionally,it was suggested that the chain length of PVP does not affect either the size of the Au NPs or the ablation efficiency.Videography experiments were conducted to explore the ablation mechanism employed by the MCL system.The relatively short pulse duration of the MCL system may contribute to the formation of NPs with consistent size,which were suppressed to grow in significantly smaller cavitation bubbles with short lifetimes.

Controlled Synthesis of PCL/PVP Copolymer by RAFT Method and Its HydrophUic Block-Dependent MiceUar Behaviors

A range of poly（ε-caprolactone）/poly（N-vinyl-2-pyrrolidone） amphiphilic block copolymers with well-defined hydrophilic chain length were synthesized by the living/controlled reversible addition fragmentation chain transfer polymerization method. The composition and struc- ture of the targeted resultants were characterized with 1H NMR, 13C NMR, FT-IR spec- troscopy and gel permeation chromatography. The various block copolymers were success- fully employed to fabricate the spherical micelle with core-shell morphological structure. The poly（N-vinyl-2-pyrrolidone） block-dependent characteristics of the copolymeric micelles were investigated by fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The solubilization of the hydrophobic ibuprofen as a model drug in the micelle solution was also explored. It was found that the drug loading contents are related to the micellar morphology structure determined by hydrophilic chain length in the copolymer.

SYNTHESIS OF POLYMER-STABILIZED RUTHENIUM COLLOIDS BY LOW BOILING POINT ALCOHOL REDUCTION

Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.

Microwave-assisted synthesis of high aspect ratio ruthenium nanorods

Poly(N-vinyl-2-pyrrolidone)(PVP)-stabilized ruthenium nanorods with high aspect ratio by refluxing ruthenium(Ⅲ) chloride in n-propanol have been successfully prepared by means of a facile and rapid microwave heating for the first time.The structure and morphology of the obtained products were characterized by transmission electron microscopy(TEM),select area electron diffraction(SAED),ultraviolet-visible spectrophotometry(UV-vis),X-ray photoelectron spectroscopy(XPS) and Fourier transform spectroscopy(FT-IR).XPS analysis reveals that the nanorods were in the metallic state.TEM images showed that ruthenium nanorods had an obvious one-dimensional structure with the aspect ratio ranged from 5 to 40 nm and length up to 600 nm.SAED patterns indicated that the nanorods were single-crystalline with a hexagonal structure.