PMMA-modified divinylester/styrene resins: phase diagrams and morphologies

SCHROEDER, WALTER F.; YÁÑEZ, MARÍA J.; ARANGUREN, MIRTA I.; BORRAJO, JULIO

JOURNAL OF APPLIED POLYMER SCIENCE

Wiley Periodicals, Inc.

Año: 2006 vol. 100 p. 4539 - 4549

0021-8995

Binary and ternary experimental cloud-point curves (CPCs) for systems formulated with a low molar mass synthesized divinylester (DVE) resin, styrene (St) and poly(methyl methacrylate) (PMMA), were determined. The CPCs results were analysed with the Flory-Huggins (F-H) thermodynamic model taking into account the polydispersity of the DVE and PMMA components, in order to calculate the different binary interaction parameters and their temperature dependences. The St-DVE system is miscible in all the composition range and down to the crystallization temperature of the styrene, therefore the interaction parameter expression reported for a higher molar mass DVE was adopted. The interaction parameters obtained were used to calculate the phase diagrams of the St-PMMA and the DVE-PMMA binary systems; and that of the St-DVE-PMMA ternary system at three different temperatures. Quasiternary phase diagrams show liquid-liquid partial miscibility of the St-PMMA and DVE-PMMA pairs. At room temperature the St-DVE-PMMA system is miscible at all compositions. Final morphologies of PMMA modified cured St-DVE materials were generated by polymerization induced phase separation (PIPS) mechanism from initial homogeneous mixtures. SEM and TEM micrographs were obtained in order to analyze the generated final morphologies, which showed a direct correlation with the initial miscibility of the system.