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Search results for: SYNTHESIS OF POLYURETHANES
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A mathematical model of rheological behavior of novel bio-based isocyanate-terminated polyurethane prepolymers
PublicationIn this paper, the results of rheological study on isocyanate-terminated polyurethane prepolymers, containing modified soybean oil residues incorporated into the chemical structure are described. Isocyanate-terminated prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate and the mixture of hydroxylated soybean oil and commercial polyether. The measurements were performed by using rotary rheometer R/S-CPS+ (Brookfield,...
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Effect of ground tire rubber on structural, mechanical and thermal properties of flexible polyurethane foams
PublicationFlexible polyurethane foams were modified with two kinds of ground tire rubber, untreated and thermo-mechanically reclaimed. A reclamation process was performed in auto-thermal conditions, which reduced the cost of the process and decreased the environmental impact of devulcanization (e.g., emission of gases). The reclamation process was carried out in a continuous manner using a co-rotating twin screw extruder. The foams were...
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Structure, morphology and mechanical behaviour of novel bio-based polyurethane composites with microcrystalline cellulose
PublicationThe aim of this work was to obtain bio-based polyurethane composites using biocomponents such as, bio-glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The prepolymer method was used to prepare the bio-based polyurethane matrix. Prepolymer synthesised from 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% wt. commercial polyether and 25% wt. hydroxylated soybean oils (H3)...
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Dielectric properties of modified graphene oxide filled polyurethane nanocomposites and its correlation with rheology
PublicationThis study aims at investigating the dynamic mechanical, dielectric and rheological properties of reinforced polyurethane (PU) nanocomposites containing hydrophilic graphene oxide (GO) and/or hydrophobic modified graphene oxide (mGO) sheets. The organic modification of GO was performed with 4,4′-methylenebis (phenyl isocyanate) (MDI) and the samples were prepared by solvent mixing. We found that addition of mGO provides a more...
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Fabrication of Composite Polyurethane/Hydroxyapatite Scaffolds Using Solvent-Casting Salt Leaching Technique
PublicationScaffolds are porous three-dimensional structures which are used to fill bone losses and make them possible to cells to grow. Many different structural and biological properties are required from them: porosity, mechanical strength and biocompability. The present research is aimed at development of composite polyurethane/hydroxyapatite scaffolds by using the solvent-casting salt leaching method. The SEM examinations were applied...
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Microstructure, mechanical properties, and flame retardancy of nanoclay-incorporated polyurethane flexible foam composites
PublicationThe present work seeks to investigate microstructure, mechanical properties, and flame retardancy of polyurethane/nanoclay flexible foam composites. In this regard, we prepared various nanocomposites with and without nanoclay and observed the resulting morphologies to correlate them with the other corresponding characteristics. The results provided support for the fact that tensile strength and compression set will increase with...
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Rigid polyurethane foams modified with ground tire rubber - mechanical, morphological and thermal studies
PublicationRigid polyurethane foams, prepared by a single step method, were modified with the two types of ground tire rubber particles, i.e. untreated and thermo-mechanically reclaimed by using a co-rotating twin screw extruder. The foaming process as well as the structure and the physical, mechanical and thermal properties of the resulting foams were investigated. The presence of ground tire rubber decreased the velocity of polymerization....
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Morphology and the physical and thermal properties of thermoplastic polyurethane reinforced with thermally reduced graphene oxide
PublicationIn this study, thermally reduced graphene oxide (TRG)-containing polyurethane nanocomposites were obtained by the extrusion method. The content of TRG incorporated into polyurethane elastomer systems equaled 0.5, 1.0, 2.0 and 3.0 wt%. The morphology, static and dynamic mechanical properties, and thermal stability of the modified materials were investigated. The application of TRG resulted in a visible increase in material stiffness...
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Weathering Resistance of Waterborne Polyurethane Coatings Reinforced with Silica from Rice Husk Ash
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Strontium-based nanosized phosphates as anticorrosive fi llers of epoxy and polyurethane coating compositions
PublicationAnticorrosive epoxy and polyurethane coatings were compounded using zinc-free nanosized phosphates of strontium (SP) or strontium and aluminum (SAP). For comparison, a nanosized calcium aluminum ammonium phosphate (CAP) and a microsized zinc phosphate (ZP) were tested. Results of salts spray and cyclic corrosion tests revealed better anticorrosive properties of the SAP-based coatings...
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Nanosize effect of clay mineral nanoparticles on the drug diffusion processes in polyurethane nanocomposite hydrogels
PublicationStudies of swelling and release of naproxen sodium (NAP) solution by polyurethane nanocomposite hydrogels containing Cloisite® 30B (organically modified montmorillonite (OMMT)) have been performed. Polyurethane nanocomposite hydrogels are hybrid, nontoxic biomaterials with unique swelling and release properties in comparison with unmodified hydrogels. These features enable to use nanocomposite hydrogels as a modern wound dressing....
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Medical-Grade PCL Based Polyurethane System for FDM 3D Printing—Characterization and Fabrication
PublicationThe widespread use of three-dimensional (3D) printing technologies in medicine has contributed to the increased demand for 3D printing materials. In addition, new printing materials that are appearing in the industry do not provide a detailed material characterization. In this paper, we present the synthesis and characterization of polycaprolactone (PCL) based medical-grade thermoplastic polyurethanes, which are suitable for forming...
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Polyurethane based hybrid ciprofloxacin-releasing wound dressings designed for skin engineering purpose
PublicationPurpose Even in the 21st century, chronic wounds still pose a major challenge due to potentially inappropriate treatment options, so the latest wound dressings are hybrid systems that enable clinical management, such as a hybrid of hydrogels, antibiotics and polymers. These wound dressings are mainly used for chronic and complex wounds, which can easily be infected by bacteria. Materials and methods Six Composite Porous Matrices...
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Recycling of Waste Rubber by the Manufacturing of Foamed Polyurethane-Based Composites—Current State and Perspectives
PublicationWorn car tires are disruptive waste, and the issue of their management is crucial for the natural environment. In many countries, the primary method of end-of-life tires utilization is energy recovery. However, more effective and beneficial for the environment is material recycling. Using them for the production of polymer-rubber composites seems to be an auspicious direction of research. Incorporation of ground tire rubber into...
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Polyurethane Composite Scaffolds Modified with the Mixture of Gelatin and Hydroxyapatite Characterized by Improved Calcium Deposition
PublicationThe skeleton is a crucial element of the motion system in the human body, whose main function is to support and protect the soft tissues. Furthermore, the elements of the skeleton act as a storage place for minerals and participate in the production of red blood cells. The bone tissue includes the craniomaxillofacial bones, ribs, and spine. There are abundant reports in the literature indicating that the amount of treatments related...
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Effect of bio-based components on the chemical structure, thermal stability and mechanical properties of green thermoplastic polyurethane elastomers
PublicationIt seems to be obvious that conditions changes during polyols synthesis have impact on the polyols properties. Even the chemical formula is the same or similar, physicochemical properties and also molecular weight of polyols might be different and are significant in term of future polyurethanes properties and processing. In this work, fully bio-based poly(propylene succinate)s synthesized at different temperature conditions were...
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Efficient Method for the Synthesis of Functionalized Basic Maleimides
PublicationA three-step procedure involving Diels-Alder condensation of maleic anhydride with furane, formation of N-substituted imide upon reaction with appropriate diamine and a final retro Diels-Alder regeneration of the maleic carbon-carbon double bond is proposed for an unequivocal synthesis of N-substituted basic maleimides. The novel method is characterized by mild reaction conditions, easy work-up, high yields and no need for additional...
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Synthesis of Combretastatin A-4 Analogs and their Biological Activities
PublicationCombretastatin A-4 (CA-4) is a natural product, which consists of two phenyl rings, linked by an ethylene bridge. CA-4, inhibitor of polymerization of tubulin to microtubules, possesses a strong antitumor and anti-vascular properties both in vitro and in vivo. Previous studies showed that disodium phosphate salt of CA-4, a water-soluble prodrug is well tolerated at therapeutically useful doses. However, it should be noted that...
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Novel and Efficient Methods for the Synthesis of Symmetrical Trisulfides
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Molten salt synthesis of conducting and superconducting ceramics
PublicationPublikacja przedstawia wyniki badań nadprzewoników oraz przewodników jonowych metodą syntezy w stopionej soli.
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Python based high-level synthesis compiler
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Synthesis, spectroscopic and photophysical properties of novel styryldiazepinoporphyrazine
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Efficient Synthesis of Functionalized Unsymmetrical Dialkyl Trisulfanes
PublicationWe have developed a convenient method for the synthesis of functionalized unsymmetrical dialkyl trisulfanes under mild conditions in very good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives with alkyl disulfanyl anions generated in situ from S-acetyl disulfanyl derivatives and sodium methoxide. The developed method allows for the preparation of...
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Synthesis, single crystal growth and properties of Sr5Pb3ZnO12
PublicationAbstract The novel Sr5Pb3ZnO12 oxide was synthesized by the solid-state reaction method. The crystal structure was studied by means of the powder x-ray diffraction Rietveld method and was found to be similar to 3 other previously known Sr5Pb3MO12 compounds (M = Co, Ni, Cu). Crystals of several hundred microns in size of the new phase were grown in molten sodium chloride and imaged using confocal optical and scanning electron microscopy....
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Novel and Efficient Methods for the Synthesis of Symmetrical Trisulfides
PublicationWe have developed a convenient methods for the synthesis of symmetrical trisulfides under mild conditions in very good yields. The described methods are based on the straightforward preparation of 5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinane-2-disulfanyl derivatives from readily available 5,5-dimethyl-2-sulfanyl-2-thioxo-1,3,2-dioxaphosphorinane or bis(5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl) disulfide. The symmetrical...
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Synthesis and structural investigation of N-acyl selenophosphoramides
PublicationN-acylowane amidy kwasu O,O-neopentylidenomonoselenofosforowego, w zależności od podstawnika na atomie azotu, krystalizują jako konformery zawierające selen w pozycji ekwatorialnej bądź aksjalnej. Wyniki tych eksperymentów wyjaśniono działaniem efektu anomerycznego.
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Behavioral antecedents of coopetition: A synthesis and measurement scale
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DDQ-mediated synthesis of functionalized unsymmetrical disulfanes
PublicationWe developed a simple and efficient method for the synthesis of functionalized unsymmetrical disulfanes under mild conditions in good yields. The designed method is based on the reaction of bis(5,5- dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)disulfane with thiols in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The developedmethod allows the preparation of unsymmetrical disulfanes bearing additional hydroxy, carboxy,...
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Optimization of Graphene Oxide Synthesis and Its Reduction
PublicationIn this article, we present the review of the chemical methods of synthesis of graphene oxide and its reduction in order to obtain the so-called reduced graphene oxide (rGO) whose properties are similar to those of pure graphene. We also present our experiments and the results in this field and the comparison of the efficiency of different methods of synthesis as well as the reduction of graphene oxide. To characterize the obtained...
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Facile synthesis of hollow silica spheres with nanoholes
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Design and synthesis of new substrates of HtrA2 protease
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Synthesis and in silico characterization of artificially phosphorylated glycosaminoglycans
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Synthesis and properties of bismuth ferrite multiferroic flowers
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Comprehensive Evaluation of Statistical Speech Waveform Synthesis
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Chromogenic macrocyclic derivatives of azoles - synthesis and properties,
PublicationNew azocrown ethers comprising imidazoles in the macrocycle have been synthesized. Imidazole, 2-methyl-, 4-methyl-, and 4-phenylimidazole were incorporated to form macrocyclic units by coupling with the appropriate bis-diazonium salts. The syntheseswere performed under high dilution conditions. The X-ray structure of a water adduct of the 21-membered crown ether derivative of 4-methylimidazole 8 has been solved. Metal...
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Quantum dots for photocatalysis: synthesis and environmental applications
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Synthesis and structure analysis of ferrocene‐containing pseudopeptides
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Recent developments in the synthesis and biological activity of muramylpeptides
PublicationZaprezentowano przegląd literaturowy obejmujący syntezę i aktywność biologiczną nowych analogów muramylopeptydów (MDP) oraz ich potencjalne zastosowanie w terapii nowotworowej i chorób infekcyjnych.
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Chemically modified carbon nanotubes: synthesis and implementation
PublicationNanorurki węglowe, będące alotropową odmianą węgla, wykazują bardzo interesujące właściwości. Wiele ich potencjalnych zastosowań wymaga chemicznej modyfikacji. Przedstawiono metodę wprowadzenia ugrupowań o właściwościach redoks lub o właściwościach kompleksujących na ściany boczne nanorurek węglowych. Otrzymany materiał przenoszono na podłoże stałe za pomocą techniki Langmuir-Bladgett i badano jego właściwości elektrochemiczne...
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Synthesis and electrochemical characteristics of novel dithiocarbamate polymers
PublicationNovel dithiocarbamate compounds have been obtained by reacting a linear poly(ethylenimine)polymer, MW 50,000, with CS2. The resulting anionic polymers contain, depending on the reaction conditions, up to two sulfur atoms per one nitrogen atom (approx. 40% w/w). The polymers are soluble in dimethylsulfoxide and insoluble in acetonitrile solutions. In both solvents they are electrochemically active, in the latter case as a cast film...
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Synthesis and Spectroscopic Properties of New Bis-tetrazoles
PublicationSyntheses of N,N'-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe2+, Cu2+, Zn2+, Co2+, Ni2+) were investigated by absorption and infrared spectroscopy. The UV-Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu2+ ion. Changes in UV-Vis absorption...
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A new preparation method of catalyst for ammonia synthesis
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Utilization of spent iron catalyst for ammonia synthesis
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Synthesis and antibacterial properties of Fe3O4-Ag nanostructures
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Synthesis of parametric images in the medical active thermography
PublicationArtykuł przedstawia zastosowanie nowej metody syntezy obrazów w termografii dla potrzeb opisu ilościowego właściwości termicznych tkanek. opis taki umożliwia różnicowanie przypadków medycznych. Metodę zastosowania dla licznych pomiarów fantomowych oraz in vitro. Przedstawiono i omówiono rezultaty prac.
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New chromogenic azothiacrown ethers - synthesis and properties
PublicationOtrzymano nowe chromogeniczne chromojonofory z atomami siarki i dwiema grupami azowymi w makrocyklu. Związki te zastosowano w membranowych elektrodach jonoselektywnych i badano właściwości elektrod w stosunku do jonów metali alkalicznych i przejściowych. Kompleksowanie azotiakoron z jonami metali badano też w układzie dioksan-woda (1:1) metodami spektroskopowymi. Oznaczono stałe trwałości kompleksów miedzi i srebra. W przeciwieństwie...
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Chromogenic Macrocyclic Derivatives of Azoles - Synthesis and Properties
PublicationOpisano syntezę makrocyklicznych azokoron zawierających resztę pirolu i imi-dazolu w makropierścieniu. Zbadano zdolność kompleksowania kationów metaliprzez otrzymane związki makrocykliczne przy pomocy spektrofotometrii UV-Visw acetonitrylu. Zbadano także właściwości jonoforowe związków w membranowychelektrodach jonoselektywnych. Ustalono strukturę krystalograficzną 18-czło-nowej pochodnej pirolu.
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Acylic congener of cucurbituril: synthesis and recognition properties.
PublicationZaprezentowano syntezę analogów acyklicznych cucurbiturilu oraz ich zdolności do kompleksowania wybranych 16 amin, dioli, kwasów dikarboksylowych, pochodnych guanidyny oraz pirydyny. Obserwowane tworzenie kompleksów przebiegało około 180 razy słabiej niż dla cucurbiturilu. Wyniki te świadczą o potencjalnych możliwościach zbliżonych do analogów cyklicznych pod względem tworzenia kompleksów i rozpoznawania wyżej wymienionych...
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Robust H- optimal synthesis of FDI systems
PublicationDetekcję błędów występujących w nadzorowanym obiekcie dynamicznym, stanowią-cą podstawę decyzji diagnostycznych, oprzeć można na analizie wektorów resz-towych, generowanych w układzie zawierającym odpowiednio zaprojektowany od-porny estymator stanu danego obiektu. Rozważano tylko zewętrzny aspekt syn-tezy generatora reszt optymalnych ze względu na normę tej przestrzeni H : toznaczy problem odprzęgania wektora resztowego od niemierzalnych...
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Synthesis of autonomous underwater vehicle control system.
PublicationArtykuł dotyczy parametrycznej identyfikacji systemu sterowania autonomicznego pojazdu podwodnego.Badania opierają sie na modelu pojazdu o 4 stopniach swobody, zrealizowanym w środowisku programowym Matlab/Simulink. Zastosowano wielowymiarowy nieliniowy regulator PID. Przedstawiono wyniki symulacji zaprojektowanego układu sterowania.