Search results for "RAV"
showing 10 items of 5866 documents
Nanocomposites based on esterified colophony and halloysite clay nanotubes as consolidants for waterlogged archaeological woods
2017
We have designed an innovative protocol for the consolidation of waterlogged archaeological woods by using acetone mixtures of halloysite clay nanotubes and a chemically modified colophony (Rosin). Firstly, we have investigated the thermal properties of HNTs/Rosin nanocomposites, which have been prepared by means of the casting method from acetone. The HNTs content have been systematically changed in order to study the influence of the inorganic filler on the thermal stability and glass transition process of Rosin. We have observed that the thermal properties of the hybrids are affected by the specific HNTs/Rosin interactions. Then, acetone dispersions of HNTs/Rosin composites at variable f…
Thermal Stability and Flame Retardancy of Polypropylene Composites Containing Siloxane-Silsesquioxane Resins
2018
A novel group of silsesquioxane derivatives, which are siloxane-silsesquioxane resins (S4SQ), was for the first time examined as possible flame retardants in polypropylene (PP) materials. Thermal stability of the PP/S4SQ composites compared to the S4SQ resins and neat PP was estimated using thermogravimetric (TG) analysis under nitrogen and in air atmosphere. The effects of the non-functionalized and n-alkyl-functionalized siloxane-silsesquioxane resins on thermostability and flame retardancy of PP materials were also evaluated by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and by cone calorimeter tests. The results revealed that the functionalized S4SQ resins may for…
Synthesis and characterisation of a ternary composite of polyaniline, reduced graphene-oxide and chitosan with reduced optical band gap and stable aq…
2019
A ternary composite comprising of p-toluene sulfonic acid doped polyaniline (PANI), chitosan and reduced graphene oxide (RGO) with stable aqueous dispersibility has been synthesised via oxidative polymerisation of aniline in chitosan/RGO dispersion. For comparison; PANI, PANI/chitosan and PANI/RGO composites were also synthesised using the same procedure. FTIR, Raman, XPS, XRD and UV-VIS confirmed the successful synthesis of the PANI and the composites. The aqueous dispersions of the PANI/chitosan and the ternary composites were found to be stable even after more than four months. The stability of the dispersion was attributed to the polycationic nature of the chitosan. The thermogravimetri…
A new eco-friendly chemical treatment of natural fibres: Effect of sodium bicarbonate on properties of sisal fibre and its epoxy composites
2016
Abstract Several researchers have shown how sisal fibres possess remarkable tensile properties that yield them good candidates as reinforcement in biocomposite materials. This work aims to evaluate the effect of an eco-friendly and cost effective surface treatment method based on the use of commercial sodium bicarbonate (i.e. baking soda) on properties of sisal fibre and its epoxy composites. In particular, raw sisal fibres were treated with a 10%w/w of sodium bicarbonate solution for different periods (24, 120 and 240 h), at room temperature. Changes occurring in sisal fibres were characterized through scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric…
Preparation, characterization and in vitro test of composites poly-lactic acid/hydroxyapatite scaffolds for bone tissue engineering.
2018
Abstract In this work, the possibility to produce composite Poly-L-lactic acid (PLLA)/Hydroxyapatite (HA) porous scaffolds via Thermally Induced Phase Separation (TIPS) for bone tissue engineering applications was investigated. Several PLLA/HA wt/wt ratios (95/5, 90/10, 70/30, 50/50, 34/66) were tested and the as-obtained scaffolds were characterized via Scanning Electron Microscopy, Wide Angle X-Ray Diffraction, Thermogravimetric analysis, Gas Pycnometry, Differential Scanning Calorimetry and mechanical compression test. Morphological analysis revealed an open structure with interconnected pores and HA particles embedded in the polymer matrix. Finally, cell cultures were carried out into t…
From Layered Molybdic Acid to Lower-Dimensional Nanostructures by Intercalation of Amines under Ambient Conditions
2006
Nanostructures of varied dimensionality such as rods, scrolls, and disks of molybdenum oxide have been synthesized in gram quantities under ambient conditions using exfoliation of the layers as a synthetic tool. Intercalation of alkylamines (CnH2n+2NH2, where n = 3, 4, 8, 12, and 16) into yellow molybdic acid (MoO3·2H2O) and subsequent treatment with nitric acid resulted in molybdenum oxide nanorods, nanodisks, or oxide−amine composite nanorods. The sizes of the nanoparticles range from a few nanometers to micrometers in length and 10 to 200 nm in diameter. Detailed X-ray, scanning electron microscopy, and transmission electron microscopy analyses reveal an inverse relation between the size…
Ceria-based electrolytes prepared by solution combustion synthesis: The role of fuel on the materials properties
2016
Ce0.8Sm0.2O2 â xpowders were synthesized by solution combustion synthesis using citric acid, cellulose and sucrose as single, or intimately mixed, fuels. The powders were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2sorption at â196 °C, H2-temperature programmed reduction and thermogravimetric analyses. Textural properties of the powders were shaped by the peculiar employed fuel. The study of reducibility revealed that oxygen vacancies formation is mainly influenced by both parameters, specific surface area and total pore volume. The different tendency toward reduction played a key role in sintering under reducing atmosphe…
Artichoke (Cynara cardunculus L.) fibres as potential reinforcement of composite structures
2011
Abstract The aim of this paper is to examine the use of artichoke fibres as potential reinforcement in polymer composites. The fibres are extracted from the stem of artichoke plant, which grows in Southern Sicily. In order to use these lignocellulosic fibres as potential reinforcement in polymer composites, it is fundamental to investigate their microstructure, chemical composition and mechanical properties. Therefore, the morphology of artichoke fibres was investigated through electron microscopy, the thermal behaviour through thermogravimetric analysis and the real density through a helium pycnometer. The chemical composition of the natural fibres in terms of cellulose, lignin, and ash co…
Carbon nanotubes-based nanohybrids for multifunctional nanocomposites
2017
In the present work, nano-hybrids based on carbon nanotubes (CNTs) bearing immobilized, either through covalent linkage and physical absorption, commercial anti-oxidant molecules have been formulated and used as nanofillers in Ultra High Molecular Weight Polyethylene (UHMWPE), aiming at preparing multifunctional nanocomposites. The effective immobilization of the anti-oxidant molecules has been probed by spectroscopic and thermogravimetric analyses. The study of the morphology and the rheological behaviour of the nanocomposites show that the immobilization of anti-oxidant molecules onto the CNTs surface is beneficial for the state of the polymer/nanoparticles interfacial region. Additionall…
Non-isothermal thermogravimetry as an accelerated tool for the shelf-life prediction of paracetamol formulations
2021
Abstract In this work, non-isothermal thermogravimetric studies have been carried out on several paracetamol formulations with the aim to predict their shelf-lives under variable storage conditions. Specifically, paracetamol tablets of different brands have been investigated allowing to estimate their pharmaceutical quality by considering the specific drug stability. The proposed protocol is based on the kinetic study of thermogravimetric data by the combination of isoconversional procedures (Friedman and Kissinger-Akahira-Sunose (KAS) methods) and “Master plot” analysis. Accordingly, the kinetics of the paracetamol degradation is totally explored in terms of activation energy, pre-exponent…