نتایج جستجو برای: polyurethane
تعداد نتایج: 6803 فیلتر نتایج به سال:
In this study, a simple and versatile synthetic approach was developed to prepare bactericidal polyurethane coatings. For this purpose, introduction of both quaternary ammonium salts (QASs), with well-known antibacterial activity, and reactive hydroxyl groups on to the backbone of soybean oil was considered. Epoxidized soybean oil was reacted with diethylamine and the intermediate tertiary amin...
A bacterium capable of degrading pendimethalin was isolated from the contaminated soil samples and identified as Bacillus lehensis XJU based on 16S rRNA gene sequence analysis. 6-Aminopendimethalin and 3,4-dimethyl 2,6-dinitroaniline were identified as the metabolites of pendimethalin degradation by the bacterium. The biodegradation of pendimethalin by freely suspended and the immobilized cells...
Cell attractive or non-attractive surface properties of polyurethane devices can be controlled by treating them with zirconium tetra(tert-butoxide). This gives reactive interfacial zirconium complex species that can be used subsequently to bond cell attractive peptides such as arg-gly-asp (RGD) or cell non-attractive organics such as polyethylene glycol (PEG) to the device surface. Control of t...
Multi-walled carbon nanotubes (MWCNTs) functionalized with amine and carboxyl groups were used to prepare polyurethane/ MWCNT nanocomposites in two distinct concentrations: a lower value of 1 mass% (spray coating) and a higher one of ~50 mass% (buckypaper based). The MWCNT-NH 2 sample contained only 0.5 mass% of amine groups, whereas MWCNT-COOH contained 5 mass% of carboxyl groups. The MWCNT fu...
Thermosetting polyurethane polymers are staples of adhesive and sealant formulations used in a variety of industrial applications. Polyurethane materials generally provide reliable service under most application conditions, but the long-term performance and durability of some polyurethanes can be compromised by direct and prolonged contact with bulk water or high ambient humidity. The Dow Chemi...
Indoor residential pesticide applications present the potential for human exposures, particularly for small children. Personal contact with target and nontarget surfaces can result in transfer of pesticides to the skin, but the magnitude of such transfer is uncertain. This research compared surface sampling techniques [wipe and polyurethane foam (PUF) roller] with the removal ability of human s...
A fast and sensitive on-line procedure for the determination of zinc in water and biological samples was developed. Zinc was preconcentrated in a mini-column packed with polyurethane foam (PUF) chemically modified with zincon via -N=N- bonding. The optimal conditions for preconcentration were pH 8.5 and sample flow rate of 4.0 mL min(-1). Quantitative desorption of Zn(II) was obtained by 0.1 mo...
The extracellular stability versus intracellular drug release and the long blood stream circulation versus enhanced cell uptake are two dilemmas for micellar drug delivery systems. To resolve the above two problems, a novel core cross-linked polyurethane micelles with redox sensitive and pH-responsive surface charge switchable properties were prepared and investigated as anti-cancer drug carrie...
Flexible and semi-rigid polyurethane foams have been widely used in automotive interior parts, residential upholstered furniture and bedding. In these, as well as other end use industries, a reduction of Volatile Organic Compounds (VOCs) emissions from polyurethane foams continues to be an important issue [1, 2]. To address this challenge, reactive amine catalysts, which have an active hydrogen...
Anisotropic polymer foams have been prepared, which exhibit a Poisson's ratio exceeding 1, and ratios of longitudinal to transverse stiffness exceeding 50. The foams are as much as 20 times stiffer in the longitudinal direction than the foams from which they were derived. The transformation process involved applying a uniaxial stress sufficient to produce 25% to 45% axial strain to open-cell po...
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