Artículos de revistas
Ethyl stearate: ethanol binary mixtures investigated by ultrafast OKE spectroscopy, optical microscopy, dynamic light scattering, and rheology
Registro en:
Journal Of Physical Organic Chemistry. Wiley-blackwell, v. 27, n. 4, n. 316, n. 321, 2014.
0894-3230
1099-1395
WOS:000333469800013
10.1002/poc.3248
Autor
Loiola, PTC
Dias, WD
Souza, MS
Ferbonink, GF
Zaniolo, MG
Cerini, MF
Atvars, TDZ
Nome, RA
Institución
Resumen
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We report an experimental study of ethyl stearate/ethanol binary mixtures employing optical microscopy, rheology, dynamic light scattering, and femtosecond optical Kerr effect spectroscopy. Optical microscopy images show that at 25 degrees C this mixture is homogeneous up to 10wt% ethyl stearate mass fraction and it leads to crystallization of ethyl stearate from solution at higher mass fractions. Rheological measurements at 40 degrees C and 25 degrees C exhibited an increase in viscosity of the binary mixture with increasing ethyl stearate mass fraction, consistent with molar mass considerations. Moreover, closer inspection of the rheology data from 0 to 10wt% ethyl stearate mass fraction indicate a plateau in the viscosity near 10%, thus indicating how crystallization affects the rheological properties of the solution, even at 40 degrees C. Dynamic light scattering data are consistent with two major components at all mass fractions investigated: a small ethyl stearate aggregate consisting of approximately seven monomers and a micron-sized crystallite. Femtosecond time-resolved optical Kerr effect indicates slower nuclear relaxation with increasing ethyl stearate mass fraction, thus suggesting that low-frequency motions of the binary mixture are involved in the early events of crystal nucleation. Copyright (c) 2013 John Wiley & Sons, Ltd. 27 4 SI 316 321 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FAPESP [2011/12502-5, 2011/12531-5, 2012/01425-2, 2008/10593-0]