INVESTIGADORES
SOULE Ezequiel Rodolfo
artículos
Título:
Miscibility of blends of poly(methyl methacrylate) and oligodiols based on a bisphenol A nucleus and ethylene oxide or propylene oxide branches
Autor/es:
B. JAFFRENNOU; E.R. SOULÉ; F. MECHIN; J. BORRAJO,; J.P. PASCAULT; R.J.J. WILLIAMS
Revista:
POLYMER
Editorial:
ELSEVIER SCI LTD
Referencias:
Año: 2004 vol. 45 p. 7185 - 7192
ISSN:
0032-3861
Resumen:
Cloud-point curves of blends of poly(methyl methacrylate) (PMMA) with a series of oligodiols based on a bisphenol A nucleus and short
branches of poly(ethylene oxide) or poly(propylene oxide) (BPA-EO or BPA-PO), and with PEO and PPO oligomers, were obtained using a
light transmission device. Experimental results were fitted with the FloryHuggins model using an interaction parameter depending on both
temperature and composition. For PMMA/PEO and PMMA/PPO blends, the miscibility increased when increasing the size of the diol, due to
the significant decrease in the entropic and enthalpic terms contributing to the interaction parameter. This reflected the decrease in the selfassociation
of solvent molecules and in the contribution of terminal OH groups to the mismatching of solubility parameters. For
PMMA/BPA-EO blends, a decrease of the entropic contribution to the interaction parameter when increasing the size of the oligodiol was
also found. However, the effect was counterbalanced by the opposite contribution of combinatorial terms leading to cloud-point curves
located in approximately the same temperature range. For PMMA/BPA-PO blends, the interaction parameter exhibited a very low value. In
this case, the effect of solvent size was much more important on combinatorial terms than on the interaction parameter, leading to an increase
in miscibility when decreasing the oligodiol size. For short BPA-PO oligodiols no phase separation was observed. The entropic contribution
of the interaction parameter exhibited an inverse relationship with the size of the oligodiols, independent of the nature of the chains bearing
the hydroxyls and the type of OH groups (primary or secondary). This indicates that the degree of self-association of solvent molecules
through their OH terminal groups, was mainly determined by their relative sizes.