No abstract

No abstract

No abstract

Several papers have been described on the thermal stability of the sweetener, C12H19Cl3O8 (Sucralose). Nevertheless no study using thermoanalytical techniques was found in the literature. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC) and infrared spectroscopy, have been used to study the thermal stability and thermal decomposition of sweetener.

Lanthanide-based coordination compounds of molecular formula [Ln(keto) 3 (H 2 O)], where Ln¼ Gd, Eu and keto¼ ketoprofen, were synthesized and their photoluminescence features were detailed in the 12-300 K interval. The emission spectra of [Eu(keto) 3 (H 2 O)] reveal a strong dependence with the temperature, well-illustrated by an unusual large blue-shift (∼17 cm À 1) of the 5 D 0-7 F 0 transition as the temperature is raised. The arithmetic difference between the absorption spectrum of [Eu(keto) 3 (H 2 O)] with that of [Gd(keto) 3 (H 2 O)] pointed out the presence of a ligand-to-metal charge transfer (LMCT) band (320-370 nm). From the [Gd(keto) 3 (H 2 O)] phosphorescence the energy of the keto-related triplet states was determined showing a large overlap with the intra-4f 6 levels and a strong electron-phonon coupling. The high-resonance between the LMCT and triplet states and the Eu 3 þ levels leads to a strong dependence of the 5 D 0 lifetime value, typical of the presence of operative energy transfer processes.

The aim of this paper is to replace toxic coinitiators (tertiary amines) by non-toxic compounds such as glycerol and inositol (polyalcohol) in dimethacrylate resins. For this purpose, mid infrared spectroscopy (MIR) was used to calculate the monomers' degree of conversion (%DC); as well as simultaneous Thermogravimetric Analysis -Differential Thermal Analysis (TGA-DTA) and Differential Scanning Calorimetry (DSC) were conducted to evaluate thermal stability, degradation steps, and thermal events. The use of different initiator systems did not modify the thermal events or the thermal stability of each of the dimethacrylate resins. Results show a substitution of system 2 (toxicity) by system 3 (low toxicity), which had a good conversion velocity and total conversion in some monomers, is plausible.

No abstract

No abstract