نتایج جستجو برای: poly vinylpyrrolidone

تعداد نتایج: 80481  

2017
Carolina S García Paula M Uberman Sandra E Martín

Aqueous Mizoroki-Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The reaction was carried out in a short reaction time and with low catalyst loading, leadin...

2009
Eva Enz Ute Baumeister Jan Lagerwall

With the relatively new technique of coaxial electrospinning, composite fibres of poly(vinylpyrrolidone) with the liquid crystal 4-cyano-4'-octylbiphenyl in its smectic phase as core material could be produced. The encapsulation leads to remarkable confinement effects on the liquid crystal, inducing changes in its phase sequence. We conducted a series of experiments to determine the effect of v...

2014
Tatyana Gutul Emil Rusu Nadejda Condur Veaceslav Ursaki Evgenii Goncearenco Paulina Vlazan

We propose a method for the synthesis of a colloidal ZnO solution with poly(N-vinylpyrrolidone) (PVP) as stabilizer. Stable colloidal solutions with good luminescence properties are obtained by using PVP as stabilizer in the synthesis of ZnO nanoparticles by a sol-gel method assisted by ultrasound. Nanoparticles with sizes of 30-40 nm in a PVP matrix are produced as a solid product. The colloid...

Journal: :Communications in Physics 2021

In this research, Au nanoparticles were successfully synthesized by modified polyol method with commercial precursors to be gold (III) chloride trihydrate (HAuCl4·3H2O), ethylene glycol (EG), poly(vinylpyrrolidone) (PVP), sodium borohydride (NaBH4). The structure and properties of as-prepared have been investigated X ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis-NIR spec...

2013
H. C. Hao

In this research, we used the surface acoustic wave (SAW) sensor to detect chemical compounds such as ammonia, methane, and ammonia-methane mixture gases. Very low concentration of ammonia (~250 ppb) and methane (~9 ppm) can be detected by our SAW devices. And we used mesoporous carbon hollow nanosphere in Poly-N-vinylpyrrolidone (PNVP) film to increase the sensitivity to ammonia from 6.91 to 1...

2016
Daniela Obels Melanie Lievenbrück Helmut Ritter

The double alkylation of N-vinylpyrrolidone (N-VP) with 1,8-dibromooctane yields paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol-ene click reactions with 2-aminoethanethiol hydrochloride to obtain reactive am...

2009
Wen-Yin Ko Wei-Hung Chen Ching-Yuan Cheng Kaun-Jiuh Lin

Cu particles with different architectures such as pyramid, cube, and multipod have been successfully fabricated on the surface of Au films, which is the polycrystalline Au substrate with (111) domains, using the electrodeposition technique in the presence of the surface-capping reagents of dodecylbenzene sulfonic acid and poly(vinylpyrrolidone). Further, the growth evolution of pyramidal Cu nan...

2009
Wen-Yin Ko Ching-Yuan Cheng

Cu particles with different architectures such as pyramid, cube, and multipod have been successfully fabricated on the surface of Au films, which is the polycrystalline Au substrate with (111) domains, using the electrodeposition technique in the presence of the surfacecapping reagents of dodecylbenzene sulfonic acid and poly(vinylpyrrolidone). Further, the growth evolution of pyramidal Cu nano...

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