INVESTIGADORES
GALANTE Maria Jose
artículos
Título:
Role of the Intrinsic Flaws upon the Flexural Strength of a Thermoplastic Modified Epoxy
Autor/es:
M.I. GIANNOTTI; M.J .GALANTE; P.A. OYANGUREN; C.I.VALLO
Revista:
POLYMER TESTING
Editorial:
ELSEVIER SCI LTD
Referencias:
Lugar: Amsterdam; Año: 2003 vol. 22 p. 429 - 437
ISSN:
0142-9418
Resumen:
A bisphenol A-based epoxy resin (DGEBA) was modified with 15 weight percent polysulphone (PSU) and thermally
cured using 4-4diaminodiphenylsulphone (DDS). Starting from a homogeneous DGEBA/DDS/PSU mixture, the system
developed a two-phase morphology upon network formation. Dynamic mechanical analysis (DMA), transmission optical
microscopy (TOM) and scanning electron microscopy (SEM) studies showed that the system developed a co-continuous
morphology consisting of two distinct domains. One of the domains was an epoxy rich matrix containing PSU particles
while the other consisted of a dispersion of epoxy particles within a PSU rich phase. Flexural strength distributions of
unmodified and thermoplastic modified epoxy resin were obtained by testing the materials in three-point bending according
to the ASTM D790 protocol. The flexural behaviour of the epoxy resin was not improved by the presence of
thermoplastic. In addition, the thermoplastic modified epoxy resin displayed a higher data scatter compared with the
neat resin. The fracture mechanism of unmodified and thermoplastic modified epoxy resins was demonstrated to be
sensitive to the intrinsic flaw distribution. The two-parameter Weibull model, which was used to analyse the experimental
data, gave a good representation of the fracture loads distribution with regression coefficients of 0.99.