Search results for "NANOTUBES"
showing 10 items of 383 documents
Thermal stability and flammability of polyolefin/halloysite nanotubes composites
2015
Najnowsze badania w zakresie uniepalniania poliolefin są ukierunkowane na zastosowanie dodatku nanorurek haloizytowych (HNT) jako bezhalogenowego środka zmniejszającego palność, a jednocześnie zachowującego właściwości mechaniczne osnowy. Powstająca na powierzchni płonącego nanokompozytu, zawierającego HNT, warstwa tzw. zgorzeliny ogranicza przenikanie gazów oraz ciepła i zabezpiecza materiał przed dalszym paleniem. Unikatowa struktura HNT umożliwia dodatkowo pochłanianie produktów termicznego rozkładu poliolefinowej osnowy. Na podstawie dostępnej literatury dokonano oceny wpływu różnych czynników, m.in. modyfikacji nanorurek haloizytowych i/lub dodatku kompatybilizatora i/lub doboru odpowi…
Thermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes
2015
Abstract Quercetin (Q), a natural antioxidant molecule, is physically immobilized onto multi-walled carbon nanotubes (CNTs) bearing covalently-linked long-chain alkyl functional groups, and the so obtained hybrid-nanoparticles are used to prepare Ultra High Molecular Weight PolyEthylene-based nanocomposite films with enhanced thermo-oxidation resistance. The effective immobilization of the Q molecules is confirmed by spectroscopic (micro-Raman, ATR-FTIR, and FTIR) and thermo-gravimetric analyses, and the influence of the nanoparticles on the rheological behaviour and thermo-oxidative stability of the nanocomposites are investigated. Rheological analyses (linear viscoelasticity and stress re…
Multi-functional polyhedral oligomeric silsesquioxane-functionalized carbon nanotubes for photo-oxidative stable Ultra-High Molecular Weight Polyethy…
2016
Abstract Nanohybrid (phPOSS- f -CNTs) based on Carbon Nanotubes (CNTs) and Phenyl Polyhedral Olygomenric Silsesquioxane (phPOSS) have been synthesized to be used as multifunctional filler for polymer nanocomposites. The success of the functionalization procedure has been demonstrated via accurate spectroscopic, spectrometric and thermo-gravimetric analyses. The results reveal that a large portion of phPOSS is covalently linked to CNTs, while a small amount of phPOSS remains physically adsorbed due to the strong interactions coming from π electron coupling between the CNTs and phenyl rings in phPOSS. Small amounts (1 wt.%) of phPOSS- f -CNTs have been dispersed in Ultra High Molecular Weight…
Polysaccharides/Halloysite nanotubes for smart bionanocomposite materials.
2020
Biopolymers as alternative to fossils-derived polymers are attracting the interest of researcher in material science. Besides the economic advantages, the sustainability makes polysaccharides ideal candidates to prepare films and formulations. The addition of Halloysite nanotubes as green inorganic fillers was exploited to improve the physico-chemical properties and to introduce smart response abilities to the material. Halloysite is a natural tubular nanomaterial with hollow cavity and large aspect ratio. The effect of polymer charge on the morphology and mesoscopic properties of polysaccharides/halloysite nanocomposites has been highlighted. Different strategies (solvent casting, lyophili…
Effect of a new amido‐imidazolium compound as a clay modifier on properties of polypropylene composites
2021
Halloysite nanotubes (HNT) and montmorillonite (Mt) were modified by a novel, dicarboxylic fatty acid substituted amido-imidazolium chloride. It was found that the modification process of the clays by the imidazolium compound improved their dispersion in the polymer matrix, while HNT were a more beneficial filler of PP than Mt. PP/imidazolium modified HNT composites (PP/HNT-M) showed significant increase in thermo-oxidative stability, flexibility, and toughness, combined with a slight reduction in stiffness, as well as a lack of changes in crystallinity and strength, compared with neat PP. These effects were not observed for PP/Mt composites. The formation of strong interactions between the…
Cyclic moisture sorption and its effects on the thermomechanical properties of epoxy and epoxy/MWCNT nanocomposite
2019
The aim of this work was to reveal the moisture absorption&ndash
Recent Progress in the Development of Composite Membranes Based on Polybenzimidazole for High Temperature Proton Exchange Membrane (PEM) Fuel Cell Ap…
2020
[EN] The rapid increasing of the population in combination with the emergence of new energy-consuming technologies has risen worldwide total energy consumption towards unprecedent values. Furthermore, fossil fuel reserves are running out very quickly and the polluting greenhouse gases emitted during their utilization need to be reduced. In this scenario, a few alternative energy sources have been proposed and, among these, proton exchange membrane (PEM) fuel cells are promising. Recently, polybenzimidazole-based polymers, featuring high chemical and thermal stability, in combination with fillers that can regulate the proton mobility, have attracted tremendous attention for their roles as PE…
Electronic and optical properties of carbon nanotubes under pure bending
2010
The high aspect ratio of carbon nanotubes makes them prone to bending. To know how bending affects the tubes is therefore crucial for tube identification and for electrical component design. Very few studies, however, have investigated tubes under small bending well below the buckling limit, because of technical problems due to broken translational symmetry. In this Brief Report a cost-effective and exact modeling of singe-walled nanotubes under such small bending is enabled by revised periodic boundary conditions, combined with density-functional tight-binding. The resulting, bending-induced changes in electronic and optical properties fall in clear chirality-dependent trend families. Whil…
Electronic Properties of Thermal Oxides on Ti and Their Influence on Impedance and Photoelectrochemical Behavior of TiO2 Nanotubes
2017
Thermal oxidation of titaniumwas carried out at 350◦C, 450◦C, and 550◦C for 2 h or 12 h.X-rayDiffraction and Raman Spectroscopy suggest that the thermal oxides are scarcely crystallinewhen the annealing temperature is low, while both anatase and rutile are present for high annealing temperature and time. Photoelectrochemical measurements allowed estimation of a bandgap decreasing from 3.35 eV to 3.15 eV with increasing annealing temperature. The impedance spectra confirmed the formation of n-type semiconductors, with an impedance strongly decreasing on going from a reverse bias toward a forward bias regime. TiO2 nanotubes grown by anodizing Ti in NH4F and water containing ethylene glycol so…
Pickering Emulsions Based on Wax and Halloysite Nanotubes: An Ecofriendly Protocol for the Treatment of Archeological Woods
2020
A novel green protocol for the consolidation and protection of waterlogged archeological woods with wax microparticles has been designed. First, we focused on the development of halloysite nanotubes (HNTs) based Pickering emulsions using wax as the inner phase of the oil-in-water droplets. The optimization of the preparation strategy was supported by both optical microscopy and scanning electron microscopy, which allowed us to show the morphological features of the prepared hybrid systems and their structural properties, i.e., the distribution of the clay at the interface. Also, the dependence of the overall dimensions of the prepared systems on the halloysite content was demonstrated. Micr…