INTEMA 05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
artículos
Título:
Poly(methyl methacrylate)-modified vinyl ester thermosets: Morphology, volume shrinkage, and mechanical properties
Autor/es:
W. F. SCHROEDER; J. BORRAJO; M. I. ARANGUREN
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
Wiley
Referencias:
Año: 2007 vol. 106 p. 4007 - 4017
ISSN:
0021-8995
Resumen:
ABSTRACT: Thermoset materials obtained from styrene/
vinyl ester resins of different molecular weights
modified with poly(methyl methacrylate) (PMMA) were
prepared and studied. Scanning electron microscopy and
transmission electron microscopy micrographs of the fracture
surfaces allowed the determination of a two-phase
morphology of the modified networks. Depending on the
molecular weight of the vinyl ester oligomer, the initial
content of the PMMA additive, and the selected curing
temperature, different morphologies were obtained,
including the dispersion of thermoplastic-rich particles in
a thermoset-rich matrix, cocontinuous structures, and the
dispersion of thermoset-rich particles in a thermoplasticrich
matrix (phase-inverted structure). Density measurements
were performed to determine the effect of the
PMMA-modifier concentration and curing temperature on
the volume shrinkage of the final materials. The development
of cocontinuous or thermoplastic-rich matrices was
not too effective in controlling the volume shrinkage of the
studied vinyl ester systems. The evaluation of the dynamic
mechanical behavior, flexural modulus, compressive yield
stress, and fracture toughness showed that the addition of
PMMA increased the fracture resistance without signifi-
cantly compromising the thermal or mechanical properties
of the vinyl ester networks.
Key words: blends; fracture; mechanical properties
