Search results for "Composites"
showing 10 items of 1905 documents
Synthesis of chemisorbed imidazolium and phosphonium cations by reaction of ionic liquid precursors with silica.
2010
The reaction of four different basic ionic liquid precursors with Aerosil®300 is presented. Chemisorbed imidazolium and phosphonium cations, with silanolate anions as part of the silicatic support, were obtained and investigated with various solid state NMR techniques.
Recognition and sensing of fluoride anion.
2009
Fluoride anion recognition is attracting a mounting interest in the scientific community due to its duplicitous nature. It is a useful chemical for many industrial applications, and it has been used in human diet, but, recently it has been accused for several human pathologies. Here we describe the ample panorama of different approaches the chemists world-wide have employed to face the challenge of fluoride binding, and we outline some of the research which in our view can contribute to the development of this field, especially when fluoride binding has to be achieved in highly competitive protic solvents and water.
An efficient synthesis of new fluorinated uracil derivativesElectronic supplementary information (ESI) available: general procedures for the preparat…
2003
A series of potentially biologically active fluorinated uracil derivatives has been prepared in three steps from oxazolines and fluorinated nitriles with good chemical yields.
Uranium( iv ) cyclobutadienyl sandwich compounds: synthesis, structure and chemical bonding
2019
The 1 : 1 reactions of uranium(IV) tetrakis(borohydride) with the sodium and potassium salts of the cyclobutadienyl anion [C4(SiMe3)4]2− (Cb′′′′) produce the half-sandwich complexes [Na(12-crown-4)2][U(η4-Cb′′′′)(BH4)3] and [U(η4-Cb′′′′)(μ-BH4)3{K(THF)2}]2. In the 1 : 2 reaction of U(BH4)4 with Na2Cb′′′′, formation of [U(η4-Cb′′′′)(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(BH4))]− reveals that a Cb′′′′ ligand undergoes an intramolecular deprotonation, resulting in an allyl/tuck-in bonding mode. A computational study reveals that the uranium–Cb′′′′ bonding has an appreciable covalent component with contributions from the uranium 5f and 6d orbitals. peerReviewed
Non-covalent graphene nanobuds from mono- and tripodal binding motifs.
2017
Graphene nanobuds were prepared via the non-covalent anchoring of C60-based molecules endowed with one or three pyrene units, respectively. TGA, FTIR, UV-Vis and TEM investigations confirmed the formation of nanohybrids. For the two molecular derivatives, striking differences were determined in their interaction with graphene or carbon surfaces by Raman, cyclic voltammetry and molecular mechanics calculations, revealing the important role of pyrene adsorption in modulating the electronic properties of the nanohybrids.
Rhodium catalyzed oxidative coupling of salicylaldehydes with diazabicyclic olefins: a one pot strategy involving aldehyde C–H cleavage and π-allyl c…
2013
An efficient one pot strategy for the synthesis of cyclopentene fused chromanone derivatives through the direct oxidative coupling of salicylaldehydes with bicyclic olefins in the presence of a rhodium-copper catalyst system is described. This is the first report on the ring opening-ring closing of bicyclic hydrazines via metal catalyzed oxidative coupling reaction.
Funkcjonalizowane woski polietylenowe jako kompatybilizatory kompozytów polietylenowo-drzewnych o wysokim stopniu napełnienia
2012
Badano proces otrzymywania kompozytów polimerowo-drzewnych o dużym stopniu napełnienia (60-80%), przygotowanych na bazie polietylenu małej gęstości (PE-LD) z udziałem komercyjnej mączki drzewnej (Lignocel C 120 i Arbocel C 320) oraz dodatkiem wosków polietylenowych sfunkcjonalizowanych poprzez ich utlenienie lub szczepienie bezwodnika maleinowego, stosowanych jako czynniki kompatybilizujące. Otrzymane materiały poddano charakterystyce określając ich podstawowe właściwości mechaniczne oraz chłonność wody. Stwierdzono, że nawet niewielka ilość wprowadzonego kompatybilizatora (2,5%), w porównaniu z próbkami otrzymanymi bez jego udziału, w istotny sposób poprawia wytrzymałość kompozytów na zerw…
Sustainable recycling technologies for thermoplastic polymers and their composites: A review of the state of the art
2022
This review article discusses the environmental and economic effects of recycling, as well as sustainable thermoplastic polymer recycling technologies. Several researchers have utilized recycled thermoplastics as matrices in the production of a variety of natural and synthetic-based composites, which is also the focus of this study. All of the industries (food and packaging, construction and building, transportation, and indoor usage) where recycled thermoplastics have a large market share (food and packaging, construction and building, transportation, and indoor usage) are covered in this review. The desirable properties of thermoplastic polymers, such as corrosion resistance, low density,…
Macro-micro relationship in nanostructured functional composites
2012
This paper examines the results of the characterization of two functional composites: Poly(methyl methacrylate) (PMMA)-Ce:YAG (yttrium aluminium garnet doped with cerium) and PMMA-cobalt hexacyanoferrate (CoHCF). The composites were prepared as possible emitters in the fields of lighting thermal sensors. The prepared composites were char- acterized using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, thermogravi- metric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses to study the correlation between micro and macro characteristics. We found that the molecular interactions of the two different fill…
Influence of Mn site doping on electrical resistivity of polycrystalline La1-yAyMn1-xBxO3 (A=Ba, Sr; B=Cu, Cr, Co) Manganites
2008
We have the measured electrical resistivity of La1-yBayMn1-xCuxO3 (0.17?y?0.30; 0.04?x?0.10), La1-ySryMn1-xCrxO3 and La1-ySryMn1-xCoxO3 (0.270?y?0.294; 0.02?x?0.10) polycrystalline samples in the 25-325 K temperature range. The increase of Mn site doping concentration leads to an increase of the electrical resistivity of the samples and the appearance of a ?double-peak? structure in the electrical resistivity versus temperature graphs. The first peak represents the insulator-metal transition in vicinity of the paramagnetic-ferromagnetic transition (TC). We have found that the intensity of the second peak increases with an increase of concentration of Mn substituents, due to the hole scatter…