نتایج جستجو برای: polymer urea

تعداد نتایج: 130317  

Journal: :Nanoscale 2012
Asli Celebioglu Tamer Uyar

High molecular weight polymers and high polymer concentrations are desirable for the electrospinning of nanofibers since polymer chain entanglements and overlapping are important for uniform fiber formation. Hence, the electrospinning of nanofibers from non-polymeric systems such as cyclodextrins (CDs) is quite a challenge since CDs are cyclic oligosaccharides. Nevertheless, in this study, we h...

Journal: :Bulletin of the Chemical Society of Japan 1970

Journal: :iranian chemical communication 2015
fariba heidarizadeh saeed asadipour

polypyrrole is one of the most useful conductive polymers, but green synthesis of this polymer has been restricted until now. the objective of the present paper is green synthesis of nano polypyrrole (ppy) by oxidative polymerization using urea-hydrogen peroxide. it was found that conductivity and morphology of polypyrrole are highly dependent on the reaction conditions such as the molar ratio ...

Journal: :Horticulturae 2022

Improvements in nitrogen (N) use efficiency reduce stress on the environment and improve tomato production. A two-year trial was conducted greenhouse tomatoes with a split-plot design, which one factor N application rate (150 kg·ha?1, N1; 200 N2; 250 N3) two other factors were type of urea applied (urea, T1; slow-release (polymer-coated) urea, T2, nitrification inhibitors (3,4-dimethylpyrazole ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Manish Kumar Mariusz Grzelakowski Julie Zilles Mark Clark Wolfgang Meier

The permeability and solute transport characteristics of amphiphilic triblock-polymer vesicles containing the bacterial water-channel protein Aquaporin Z (AqpZ) were investigated. The vesicles were made of a block copolymer with symmetric poly-(2-methyloxazoline)-poly-(dimethylsiloxane)-poly-(2-methyloxazoline) (PMOXA(15)-PDMS(110)-PMOXA(15)) repeat units. Light-scattering measurements on pure ...

2008
Shi-Shen Zhang

In the title coordination polymer, [CuI(C(13)H(14)N(4)S)](n), the Cu(I) atom is coordinated by two N atoms from two N,N'-bis-(3-pyridylmeth-yl)thio-urea ligands, as well as by the S atom of a third ligand and an I atom to confer a distorted tetra-hedral coordination at the metal centre. The coordination bonds give rise to a layer structure parallel to (010).

Polypyrrole is one of the most useful conductive polymers, but green synthesis of this polymer has been restricted until now. The objective of the present paper is green synthesis of nano polypyrrole (PPy) by oxidative polymerization using urea-hydrogen peroxide. It was found that conductivity and morphology of polypyrrole are highly dependent on the reaction conditions such as the molar ratio ...

2010
D. Isakov E. de Matos Gomes R. Reis

Nanofibers consisting of the optically nonlinear organic molecule urea embedded in both poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA) polymers were produced by the electrospinning technique. The second-harmonic generation produced by aligned fiber mats of these materials displays a strong dependence on the polarization of the incident light. In PVA-urea nanofibers the effectiveness i...

Journal: :Journal of Soil Science and Plant Nutrition 2022

Abstract Polymer-coated urea (PCU) has been traditionally used for broadcast and/or incorporated application of nitrogen (N) fertilizers. To improve N use efficiency (NUE), there an increase in sub-surface banded this fertilizer technology. However, is little information on the release and supply from PCU granules when applied a band. This research aimed to investigate spatial distribution key ...

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