Author
J. Estrela dos Santos
Bio: J. Estrela dos Santos is an academic researcher from Federal University of São Carlos. The author has contributed to research in topics: Amine gas treating & Materials science. The author has an hindex of 1, co-authored 1 publications receiving 65 citations.
Papers
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TL;DR: In this article, the effect of adding tailored substances to lower the crystallization temperature (T c ) of methyl hexadecanoate (PalMe) was studied, and it was shown that the additive can reduce the temperature by 10°C depending on the molecular mass, molecular structure and concentration of the additive.
Abstract: Solid methyl esters of saturated fatty acids can cause technological problems when modified vegetable oils are used at low temperatures. In this work the effect of adding tailored substances to lower the crystallization temperature ( T c ) of methyl hexadecanoate (PalMe) was studied. These substances were esters of carboxylic acids with linear or branched alkyl chains of up to 16 carbon atoms with alcohols having cyclic or branched alkyl chains or an alkoxy group. Results of DSC measurements have shown that the crystallization temperature of PalMe could be decreased by 10°C depending on the molecular mass, molecular structure and concentration of the additive. The best results were obtained using hexadecanoic acid derivatives.
67 citations
01 Jan 2023-Journal of Materials Chemistry C. Materials for Optical, Magnetic and Electronic Devices
TL;DR: In this article , two amine/carbonyl-based multi-resonance thermally activated delayed fluorescence (TADF) emitters have been designed and synthesized.
Abstract: Two novel -extended amine/carbonyl-based multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters have been designed and synthesized. The two emitters are isomeric, comprised of nine fused rings and show green-yellow emission....
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TL;DR: The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorptive mechanism and not involving a mass transfer in solution.
317 citations
TL;DR: In this paper, the authors used DSC curves as an alternative method to determine the degree of N-acetylation (DA) in chitin/chitosan samples, based in both peak area and height of the decomposition signal.
256 citations
TL;DR: Metal complexes of novel Schiff base (HL) ligand, prepared via condensation of 4-aminoantipyrine and 2-aminophenol, are prepared and are screened for its antibacterial activity against bacterial species.
159 citations
TL;DR: In this paper, the authors used FTIR measurements to verify the fine dispersion of silica nanoparticles in all used polymer matrices of compo- sites with low silica content.
Abstract: Various bionanocomposites were prepared by dispersing fumed silica (SiO2) nanoparticles in bio- compatible polymers like poly(vinyl pyrrolidone) (PVP), chitosan (Chi), or poly(vinyl alcohol) (PVA). For the biona- nocomposites preparation, a solvent evaporation method was followed. SEM micrographs verified fine dispersion of silica nanoparticles in all used polymer matrices of compo- sites with low silica content. Sufficient interactions between the functional groups of the polymers and the surface hydroxyl groups of SiO2 were revealed by FTIR measurements. These interactions favored fine dispersion of silica. Mechanical properties such as tensile strength and Young's modulus substantially increased with increas- ing the silica content in the bionanocomposites. Thermog- ravimetric analysis (TGA) showed that the polymer matrices were stabilized against thermal decomposition with the addition of fumed silica due to shielding effect, because for all bionanocomposites the temperature, corre- sponding to the maximum decomposition rate, progres- sively shifted to higher values with increasing the silica content. Finally, dynamic thermomechanical analysis (DMA) tests showed that for Chi/SiO2 and PVA/SiO2 nanocomposites the temperature of b-relaxation observed in tand curves, corresponding to the glass transition tem- perature Tg, shifted to higher values with increasing the SiO2 content. This fact indicates that because of the reported interactions, a nanoparticle/matrix interphase was formed in the surroundings of the filler, where the macromolecules showed limited segmental mobility. V C 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 1739-1749, 2008
158 citations
TL;DR: The adsorption kinetics followed the mechanism of the pseudo-second order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorptive mechanism and not involving a mass transfer in solution.
156 citations