Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/75496
Type: Artigo de periódico
Title: SHEAR INFLUENCE ON THE PHASE-SEPARATION OF OLIGOMER BLENDS
Author: MUNIZ, EC
NUNES, SP
WOLF, BA
Abstract: Shear influences on the phase separation behaviour of four different blends of ethylene glycol/propylene glycol oligomers, exhibiting upper critical solution temperatures, were investigated. Cloud point curves at rest (turbidity measurements) are reported for all systems, spinodal conditions (light scattering) and tie-lines (analysis of the coexisting phases) are given for some examples. Phase diagrams under shear were obtained from rheological data. They demonstrate that the demixing temperatures of systems where both glycols bear OH end-groups are lowered up to ca. 1-degrees-C by shear rates of 1000 s-1; the critical composition, generalized to the non-equilibrium conditions of flow, is markedly shifted. These observations are explained in terms of the generalized Gibbs energy (containing the mechanical energy the system stores during flow) as a consequence of the strongly interacting end-groups of the glycols. This interpretation is backed by the fact that the shear effects disappear when the glycols are methylated.
Country: Suíça
Editor: Huthig & Wepf Verlag
Rights: fechado
Identifier DOI: 10.1002/macp.1994.021950412
Date Issue: 1994
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
WOSA1994NE71900012.pdf630.21 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.