Thermodynamic Analysis of the Reaction-Induced Phase Separation in Model Systems based on Blends of a Rubber in Diepoxide / Monoamine Precursors

ILEANA A ZUCCHI; MARÍA J. GALANTE; JULIO BORRAJO; ROBERTO JJ WILLIAMS

MACROMOLECULAR SYMPOSIA

Wiley - VCH

Lugar: Weinheim; Año: 2003 p. 295 - 307

1022-1360

The reaction-induced phase separation in blends based on a carboxyl-terminated poly(butadiene-co-acrylonitrile) rubber (CTBN), dissolved in diglycidyl ether of bisphenol A (DGEBA) – benzylamine (BA) monomers, was studied. The polymerization kinetics was followed by size exclusion chromatography, for both the neat DGEBA-BA system and for blends containing 10 wt % CTBN. No effect of CTBN addition on the polymerization rate was observed within experimental error. The kinetics could be fitted with a model based on the presence of non-catalytic and OH-catalyzed reactions and assuming equal reactivity of primary and secondary amine hydrogens. Cloud-point conversions were determined at 60, 70 and 80 ºC. The Flory-Huggins model provided a reasonable fitting of experimental data using an interaction parameter depending exclusively on temperature, and taking polydispersities of both linear polymers into account. Linear epoxy/amine systems may be used to test the reliability of thermodynamic theories in more complex situations (e.g., modifiers with a broad distribution of molar masses or mixtures of several modifiers).