Ci. Vallo et al., TOUGHENED-HYBRID EPOXIES - INFLUENCE OF THE RUBBER-PHASE MORPHOLOGY ON MECHANICAL-PROPERTIES, Journal of Materials Science, 29(9), 1994, pp. 2481-2486
A toughened-epoxy polymer based on diglycidylether of bisphenol A (DGE
BA) cured with ethylenediamine (EDA) and modified with a rubber based
on an epoxy-terminated acrylonitrile-butadiene random copolymer (ETBN)
, exhibited different morphologies depending on the rubber content. Up
to 10% rubber, the morphology consisted of a random dispersion of sph
erical domains rich in rubber, while at 15% rubber, large and irregula
r domains were present, turning into a co-continuous structure at 20%
rubber. Mechanical properties (elastic modulus, uniaxial compression y
ield stress, critical stress intensity factor, K(IC) and strain energy
release rate, G(IC)) of the toughened epoxies and hybrid-particulate
materials containing glass beads, were analysed. The best mechanical p
roperties were exhibited by hybrids with a random dispersion of rubber
y domains in the epoxy matrix. The presence of large and irregular dom
ains or co-continuous structures led to materials with poor mechanical
properties.