T. Iijima et al., Preparation of novel soluble poly(ester imide)s containing a trimellitimide moiety and their use as modifiers for aromatic diamine-cured epoxy resin, POLYM INT, 50(11), 2001, pp. 1214-1222
Poly(ester imide)s, prepared by the reaction of phthalic anhydride, N-(4-ca
rboxyphenyl) trimellitimide and 1,2-ethanediol, were used to improve the to
ughness of bisphenol-A diglycidyl ether epoxy resin cured with 4,4'-diamino
diphenyl sulfone (DDS). The poly(ester imide)s include poly(ethylene phthal
ate-co-ethylene N-(1,4-phenylene) trimellitimide dicarboxylate)s (PESIs) ha
ving 10, 20 and 30 mol% trimellitimide (TI) units, respectively. PESIs havi
ng 10 and 20 mol% TI units were effective as modifiers for toughening the c
ured epoxy resin. For example, the inclusion of 20 wt% of PESI (20 mol% TI
unit, (M) over bar (W) 19300 gmol(-1)) led to a 55% increase in the fractur
e toughness (KIC) of the cured resin (with an increase in flexural strength
and modulus) and the modified resin had a particulate morphology. PESI hav
ing 30 mol% TI units was not effective because of degradation of the modifi
er by DDS. The toughening mechanism is discussed in terms of morphological
and dynamic viscoelastic behaviour of the modified epoxy resin system. (C)
2001 Society of Chemical Industry.