Search results for "thermogravimetric analysis"
showing 10 items of 212 documents
Solid state 13C-NMR methodology for the cellulose composition studies of the shells of Prunus dulcis and their derived cellulosic materials.
2020
Lignocellulosic fibers and microcellulose have been obtained by simple alkaline treatment from softwood al- mond shells. In particular, the Prunus dulcis Miller (D.A.) Webb. was considered as a agro industrial waste largely available in southern Italy. The materials before and after purification have been characterized by 13C CPMAS NMR spectroscopy methodology. A proper data analysis provided the relative composition of lignin and holo- cellulose at each purification step and the results were compared with thermogravimetric analysis and FT-IR. To value the possibility of using this material in a circular economy framework, the fibrous cellulosic material was used to manufacture a handmade c…
Silica aerogel–metal composites produced by supercritical adsorption
2010
Abstract Silica aerogel has been loaded with ruthenium acetyl acetonate (Ru(acac) 3 ) by adsorption from supercritical carbon dioxide. Adsorption isotherms and kinetics were measured at different pressures and temperatures. The properties of impregnated aerogel were obtained by optical and electron microscopy (SEM), X-ray microanalysis (EDX) and thermogravimetric analysis (TGA). Results showed that Ru(acac) 3 can be uniformly dispersed into the aerogel up to 5 wt%. Moreover, precursor loading is controllable by properly changing operating conditions. The adsorbed metallorganic compound has been reduced to elemental ruthenium by heat treatment without inducing degradation and morphological c…
Palladium supported on Halloysite-triazolium salts as catalyst for ligand free Suzuki cross-coupling in water under microwave irradiation
2015
Abstract Environmental friendly halloysite-dicationic triazolium salts (second generation) obtained by subsequent click reactions of a diyne derivative in the presence of 2-azidopropyl-modified halloysite nanotubes, were used as supports for palladium catalyst. Thanks to the high triazolium loading (25%) these materials were able to support higher amount of the metal than that on the monocationic derivative (first generation). Such materials were characterized by thermogravimetric analysis, FT-IR spectroscopy and SEM investigations. The new catalytic system was employed in the ligand free Suzuki cross-coupling under microwave irradiation. A set of solvent, time and% loading of palladium was…
Water Absorption of Hemp Fibre Nonwovens Modified with Metal and Metal Oxide Nanoparticles
2015
In this paper changes of ability of hemp fibre nonwovens to absorb water after deposition of metal and metal oxide nanoparticles were investigated. Moisture content of samples after storage in different climatic conditions was determined using thermogravimetric method. The obtained results were compared with the results of previous research based on investigation of water absorption of metalized woven fabric of bast fibre. Analysis of measurements showed that nonwoven samples with surface treated in plasma attract water slightly better than sample with untreated surface; this was more pronounced in woven fabric samples. In turn, metal coatings reduced water sorption. Unlike woven fabric sam…
Thermogravimetric analysis as express tool for quality assessment of refuse derived fuels used for pyro-gasification
2019
The development of pyro-gasification technologies makes necessary the development of new express analytical methods that are able to deal with the variability of feedstock and problems arising from it. Thermogravimetric proximate analysis of refuse derived fuels is a very fast, cheap and simple method for the determination of proximate and fractional composition. Development of this analytical approach may result in a very cost-effective method to describe wholesome composition and characteristics of feedstock used for pyrolysis and gasification processes in real time. The aim of this study was the development of such analytical method. Refuse derived fuel samples produced in Latvia and Est…
Synthesis and characterization of polyene chromophores with hydroxyl functionalization
2008
Abstract Eight hydroxyl functionalized donor–acceptor polyene chromophores 3–10 were synthesized and characterized. Knoevenagel condensation reaction of aromatic polyenals with 2-cyanoacetamide derivatives was utilized to synthesize chromophores with all-E configuration. Chromophores of this kind can be attached covalently to polymers or functionalized with dendrons in order to tune the properties. The structures of the molecules were verified by 1H NMR, 13C NMR, ESI-TOF mass spectrometry and UV–vis measurements. Reduced bond-length alternation of the molecules in DMSO-d6 solution were observed by calculating the average difference of the vicinal coupling constants between adjacent CH CH an…
Effect of halloysite nanotubes filler on polydopamine properties
2019
Abstract Hypothesis Polydopamine (PDA) is widely used as hydrophilic coating for several applications. However, most of the methods studied to improve or manipulate PDA properties are multistep and time-consuming, and there is a need for versatile strategies aimed at controlling and modifying the properties of PDA. Experiments PDA-halloysite nanocomposites were produced under different oxidation conditions in alkaline and acidic media and were characterized by UV–visible and attenuated total refraction- Fourier Transform Infrared spectroscopies, thermogravimetric analysis, porosimetry, scanning electron microscopy, X-ray diffraction and contact angle measurements against the reference PDA p…
Coordination Driven Capture of Nicotine Inside a Mesoporous MOF.
2017
Metal organic frameworks (MOFs) are a wide class of crystalline porous polymers studied in many fields, ranging from catalysis to gas storage. In the past few years, MOFs have been studied for the encapsulation of organic or organometallic molecules and for the development of potential drug carriers. Here, we report on the study of two structurally-related mesoporous Cu-MOFs, namely PCN-6 and PCN-6′ (PCN stands for Porous Coordination Network), for nicotine trapping. Nicotine is a well-known alkaloid liquid molecule at room temperature, whose crystalline structure is still unknown. In this work, the loading process was monitored by electron ionization mass spectrometry by using a direct ins…
The anion impact on the self-assembly of naphthalene diimide diimidazolium salts
2017
Naphthalene diimide diimidazolium salts differing in the anion nature were synthesized and their properties as well as their self-assembly behaviour were investigated. In particular, we took into consideration the N,N′-bis-(1-octyl-3-propylimidazolium)-naphthalene diimide cations and anions differing in size, shape and coordination abilities like [I−], [BF4−] and [NTf2−]. After determination of thermal behaviour, using differential scanning calorimetry and thermal gravimetric analysis, the electrochemical stability and redox properties were assessed using cyclic voltammetry. The self-assembly behaviour of the salts was investigated using concentration and temperature-dependent spectroscopic…
Insights into grafting of (3-Mercaptopropyl) trimethoxy silane on halloysite nanotubes surface
2020
Abstract Functionalization of halloysite nanotubes surface by using organosilanes is sensitive to the reaction conditions. Halloysite nanotubes (HNTs) were modified using (3-Mercaptopropyl) trimethoxy silane (MPTMS). The experiments were performed under different reaction conditions including, various solvents [Toluene, Tetrahydrofuran (THF), Ethanol, n-Hexane, 1,4 Dioxane and Acetonitrile], water content in the reaction media, volume of solvent, number of moles of silane and catalysts (triethyl amine, ammonia solution and tetra-ethoxy titanium). The elemental analysis, FT-IR analysis were used to identify the samples, which attained the highest percent of functionalization. SEM image and t…