Reaction Induced Phase Separation in an Epoxy/Low Molecular Weight System

E. R. SOULÉ; M. GARCÍA DE LA MATA; J. BORRAJO; P. A. OYANGUREN; M. J. GALANTE

JOURNAL OF MATERIALS SCIENCE

SPRINGER

Año: 2003 vol. 38 p. 2809 - 2814

0022-2461

Blends based on a stochiometric mixture of diglycidyl ether of bísphenol A (DGEBA} and 2 (ACHM) and cyclohexane as low molecular weight solvent were studied. The polymerization kinetics data experimentally obtained at different temperatures (30 6O°C were accurate fitted using a mechanistic model. The effect of the solvent over the polymerization rate was analyzed. No influence of the presence of the solvent was found up to 20 wt% of cyclohexane in the sample The thermodynamic analysis using Flory-Huggins model allowed determination of the initial miscibility of binary blends containing DGEBA/cyclohexane and pseudo-binary mixtures of DGEBA/ACHM/cyclohexane. The presence of ACHM increases the DGEBA/cyclohexane initial solubility. The reaction-induced phase separation was described using a conversion-composition transformation phase diagram. It indicates that phase separation takes place by a nucleation and growth (NG) mechanism. The appropriate selection of composition of the b and polymerization conditions led to final materials with a desired closed celI porous morphology.