Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/65692
Type: Artigo de periódico
Title: Ethyl stearate: ethanol binary mixtures investigated by ultrafast OKE spectroscopy, optical microscopy, dynamic light scattering, and rheology
Author: Loiola, PTC
Dias, WD
Souza, MS
Ferbonink, GF
Zaniolo, MG
Cerini, MF
Atvars, TDZ
Nome, RA
Abstract: 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.
Subject: ethyl stearate
nucleation
ultrafast
Country: EUA
Editor: Wiley-blackwell
Rights: fechado
Identifier DOI: 10.1002/poc.3248
Date Issue: 2014
Appears in Collections:Unicamp - Artigos e Outros Documentos

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