Authors:S. Tarulli, O. Quinzani, J. Dristas, and E. Baran
Complexes of Cu(II) with substituted o-acetoxy benzoic acids (5-haloaspirines, X-asp) with and without pyridine (py), of composition
[Cu2(X-asp)4] and [Cu(X-asp)2(py)2 ] have been synthesized and characterized. Electronic and vibrational spectroscopic data of these complexes are reported.
Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis. In all complexes, the haloaspirinate
ligands decompose in two or three steps, starting with the break up of the coordinated acetoxy groups. CuO is obtained as
the final pyrolysis residue in all cases.
Authors:T. Vlase, Gabriela Vlase, Dorina Modra, and N. Doca
Thermal behavior of four food
dyes, i.e. tartrazine, crysoine, azorubine and amarant was studied under non-isothermal
conditions, in dynamic air atmosphere and at heating rates of 5, 10, 15 and
20C min–1. The TG data were correlated
to the FTIR spectra of each sample, before and after the thermal decomposition.
Kinetic study by processing the TG data was performed. The main conclusion
of this study is that the non-parametric kinetic method allows a separation
of the steps of a complex process and that the values of the activation energy
obtained by this method agree satisfactory with that of Flynn–Wall–Ozawa
Authors:Amanda dos Santos, G. Chierice, A. Riga, K. Alexander, and Ellen Matthews
Eugenol is an allyl chain-substituted guaiacol in the biosynthesized phenylpropanoid compound class derived from Syzygium aromaticum L. and widely used in folk medicine. Nonetheless, its pharmacological use is limited by some problems, such as instability
when exposed to light and high temperature. In order to enhance stability, the eugenol molecule was structurally modified,
resulting in eugenyl acetate. The eugenyl acetate’s thermal behavior and crystal structure was then characterized by differential
scanning calorimetry (DSC) and X-ray diffraction (XRD) and compared to a commercial sample.
The Mössbauer spectra of Sm2Fe17Nx, prepared by the nitrogenation of Sm2Fe17 powders in an ammonia and hydrogen atmosphere, were observed at elevated temperatures to shed light on the thermal behavior
of nitrogen in the compounds Sm2Fe17Nx. It was found that there were large differences in thermal behavior between the starting Sm2Fe17, crystalline Sm2Fe17Nx (x≈1.7) and amorphous Sm2Fe17Nx(x∼7).
The thermal decomposition behavior of Sm2Fe17N3.2, developed as one of the most promising hard magnetic materials, was found to be different under different atmospheres.
Authors:Rodica Olar, Mihaela Badea, Dana Marinescu, and Ramona Mardale
derivatives, new complexes with such units incorporated in Schiff bases ligands have been synthesized and characterized. The complexes have been characterized by different analytical and spectral methods.
The thermalbehaviour of these derivatives was
Authors:Mihaela Badea, Rodica Olar, Dana Marinescu, and Gina Vasile
A series of new complexes with mixed ligands of the type [ML(C3H3O2)2]·nH2O (((1)M=Mn, n=1; (2)M=Co(II), n=2; (3)M=Ni(II), n=4; (4)M=Cu(II), n=1.5; (5)M=Zn(II), n=0; L=3-amino-1,2,4-triazole and (C3H3O2)=acrylate anion) were synthesized and characterised by chemical analysis and IR data. In all complexes the 3-amino-1,2,4-triazole
acts as bridge while the acrylate acts as bidentate ligand except for complex (5) where it is found as unidentate. The thermal behaviour steps were investigated in nitrogen flow. The thermal transformations
are complex processes according to TG and DTG curves including dehydration, acrylate ion and 3-amino-1,2,4-triazole degradation
respectively. The final products of decomposition are the most stable metal oxides, except for complex (4) that leads to metallic copper.
Authors:X. Han, Y. Hu, Z. Lin, S. Li, F. Zhao, Z. Liu, J. Yi, L. Zhang, and X. Ren
Effects of fullerenes including FS, EFS and pure C60 on thermal behaviors of polyethylene glycol (PEG) have been studied by employing thermogravimetry-differential thermogravimetry
(TG-DTG), differential scanning calorimeter (DSC) and off-line furnace-type pyrolysis-gas chromatography/mass spectrometry
(Py-GC/MS). The products were collected by Cambridge filter pad which was widely used in analyzing the combustion products
of cigarette. The results showed that the addition of fullerenes obviously restrained the thermal decomposition of PEG. The
initial decomposition temperatures (IDT) and maximum decomposition peak temperatures (MDT) were evidently postponed by the
addition of fullerenes. Pyrolysis products with one or two hydroxyl end groups obviously increased with the addition of 10%
C60. The reasons of the changes were discussed from the aspects of reaction mechanisms.
Authors:K. Siimer, P. Christjanson, T. Kaljuvee, T. Pehk, and I. Saks
Urea–formaldehyde (UF) and phenol–formaldehyde (PF) resins are the most widely used wood adhesives. The first stage in resin
manufacturing is the formation of methylol derivatives which polycondensation leads to building the tridimensional network.
Understanding the behaviour of methylol compounds in curing provides useful information for developing appropriate resin structures.
Thermal behaviour of N,N′-dihydroxymethylurea, 2- and 4-hydroxymethylphenols, urea and phenol as model compounds for UF, PF and phenol–urea–formaldehyde
(PUF) resins was followed by TG-DTA method. The measurements were carried out by the labsys instrument Setaram at 30–450 °C in nitrogen flow. The characteristic signals for model compounds and for some reaction mixtures
were measured by high resolution 13C NMR spectroscopy.
Thermal behaviour of the
glass series (100–y)[0.5ZnO0.1B2O30.4P2O5]yTiO2
(with y=0–39 mol% TiO2)
was investigated by DSC and TMA. The addition of TiO2
results in a non-linear increase of glass transition temperature. The compositional
dependences of thermal stability, evaluated by two criteria exhibit two maxima
for the glasses doped with 10.7 and 35.9 mol% TiO2.
All the glasses crystallize on heating in the temperature range of 576–670C.
The crystallization mechanism was studied at the glasses with 19.4 and 35.9
mol% TiO2 and the results showed that surface nucleation
mechanism prevails in these glasses over the internal one.