Search results for "FT-IR"
showing 10 items of 48 documents
Hygrothermal ageing of reprocessed polylactide
2012
[EN] The influence of an accelerated hygrothermal ageing simulation test on a commercial PLA and its three subsequent mechanically-reprocessed materials was studied. The analysis was focused on the water diffusion kinetics and the physico-chemical changes induced by the hygrothermal degradation. Water diffusion proceeded faster than chain relaxation processes, as defined by a Case II absorption model. It was proved that the water diffusion rate decreased with subsequent reprocessing cycles and increased with higher hygrothermal ageing temperatures. Hydrolytic chain scission provoked significant molar mass decays and consequent general losses of thermal and mechanical performance. The rearra…
Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene
2013
Polymer nanocomposites are currently a topic of great interest. The increasing importance they are gaining also in the standpoint of industrial applications, is giving concerns regarding their environmental stability and, in general, their behaviour in outdoor applications, under direct solar irradiation. Papers available in the literature have highlighted the different influences of different nanosized fillers, in particular clay-based nanofillers; however, few data are available regarding other nanosized fillers. Furthermore, the research on polymer nanocomposites has clearly pointed out that the use of compatibilizers is required to improve the mechanical performance and the dispersion o…
Effect of Polarity of Solvent on Silanization of Halloysite Nanoclay Using (3-Glycidyloxy propyl) Trimethoxy Silane
2021
Abstract: The grafting of silane groups on clay surfaces has been recently investigated in order to fabricate versatile compounds with new potential applications in materials science and ecological engineering. This work explored the influence of variety of solvents with variable polarity on the silanization of halloysite nanoclay (HNT) surface by (3-Glycidyloxy propyl) trimethoxy silane. To this purpose, the functionalization of HNT by 3-Glycidyloxypropyltrimethoxysilane (GOPTMS) has been conducted in Ethanol (polar protic solvent), Tetrahydrofuran (THF) and Acetonitrile (polar aprotic solvents), and Hexane, 1,4-Dioxane and Toluene (non polar solvents). The silane grafted materials were ch…
Petrographic and spectroscopic (FT-IR) study of Western Mediterranean obsidians geological sources and of a lithic collection from Ustica Island (Sic…
2019
I n this study we applied petrochemical methods (SEM-EDS; FT-IR) in order to characterize a group of obsidian flakes collected at Ustica island (Sicily). Despite the absence of obsidian geological outcrops, a lot of obsidian fragments still emerging from the lands of Ustica testify that the island was a major import center of obsidian during the prehistory. On this island, there are some prehistoric settlements, dated from the Neolithic to the Middle Bronze Age (6000- 1200 BC), in which the use of obsidian continued until the beginning of metals age. Our study includes: i) Macroscopic and microscopic optical observations, which allowed selecting 18 obsidian flakes (starting from 50 obsidian…
Il cammino del sole, gli spazi del giorno. Piano urbanistico del comune di Grammichele (CT) su lastra di ardesia dipinta
2008
The synthesis, structure and properties of N-acetylated derivatives of ethyl 3-amino-1H-pyrazole-4-carboxylate.
2007
Ethyl 3-amino-1H-pyrazole-4-carboxylate (1) was yielded through total synthesis and reacted with acetic anhydride to give the acetylated products 2-6. Compounds 1-6 were studied with HPLC, X-ray, FT-IR, (1)H-NMR, (13)C-NMR and MS. Acetylation was carried out in solvents of various polarity, namely; chloroform; dioxane; DMF; acetic anhydride, at room temperature and at boiling points; and in the presence and absence of DMAP. The acetylated products are mainly nitrogen atoms in the ring. The position of the ring proton in the solution was based on NOESY; multinuclear HMBC, HSQC spectra and calculations. For equivalent amounts (1-1.5 mol) of acetic anhydride at room temperature two products of…
Annular Tautomerism of 3(5)-Disubstituted-1H-pyrazoles with Ester and Amide Groups
2019
A series of disubstituted 1H-pyrazoles with methyl (1), amino (2), and nitro (3) groups, as well as ester (a) or amide (b) groups in positions 3 and 5 was synthesized, and annular tautomerism was investigated using X-ray, theoretical calculations, NMR, and FT-IR methods. The X-ray experiment in the crystal state showed for the compounds with methyl (1a, 1b) and amino (2b) groups the tautomer with ester or amide groups at position 3 (tautomer 3), but for those with a nitro group (3b, 4), tautomer 5. Similar results were obtained in solution by NMR NOE experiments in CDCl3, DMSO-d6, and CD3OD solvents. However, tautomer equilibrium was observed for 2b in DMSO. The FT-IR spectra in chloroform …
Evolution of the optimal catalytic systems for the oxidative dehydrogenation of ethane: The role of adsorption in the catalytic performance
2022
Three samples that correspond to the evolution of optimal catalytic systems for the oxidative dehydrogenation of ethane have been synthesized and compared in terms of catalytic behavior and adsorption properties: (i) vanadium oxide supported on alumina, (ii) Sn-promoted NiO, and (iii) multicomponent MoVTeNbO with the M1 structure. The main difference in catalytic performance lies in the extent of the overoxidation of the ethylene formed, following the order VOx/Al2O3 > NiSnOx > MoVTeNb-M1. Accordingly, the selectivity to ethylene at medium and high ethane conversion follows the order MoVTeNb-M1 > NiSnOx > VOx/Al2O3. These results are confirmed by the relative reaction rates observed for the…
Scientific studies for the restoration of a wood painting of the Galleria Interdisciplinare Regionale della Sicilia—Palazzo Mirto di Palermo
2016
Abstract The Ritratto muliebre, referring to Venus, is a panel painting, oil on wood, attributed to unknown artist and probably dated to the second half of 16th century, today conserved in the Galleria Interdisciplinare Regionale della Sicilia—Palazzo Mirto of Palermo. The aim of this research was to assess the techniques used to decorate the wooden painting and to verify the state of conservation of the artwork's materials but also to identify the previous treatments. This study was the essential condition to plane and perform the correct restoration. For this reason, an integrated analytical approach based on the use of non-invasive and micro-invasive techniques was used, with the aim to …
Synthesis, Structural characterization and Exafs investigations of new ruthenium(III) complexes.
2008
Two new complexs of Ru(III) with glucosaminic acid and 1-Methyluracil, [RuCl2(Glun-N,O)2]H (I), (Glun-= glucosaminate); [RuCl4(1-MeU-N3)(DMSO)]H2.H2O (II), (1-MeU-= 1-Methyluracilate) were prepared from the same Ru(III) precursors, RuCl3•3H2O and [(DMSO)2H][trans-RuCl4(DMSO)2]. The characterization of the complexes have been carried out by elemental analysis, FT-IR, ES-MS, NMR and EXAFS.