Ra. Pethrick et al., EFFECT OF CURE TEMPERATURE ON THE STRUCTURE AND WATER-ABSORPTION OF EPOXY AMINE THERMOSETS/, Polymer international, 39(4), 1996, pp. 275-288
Dielectric and rheological measurements are reported on the effect of
cure temperature on the water absorption of tris[(2,3-epoxypropoxy)phe
nyl] methane cured with a 1:1 stoichiometric ratio of 4,4'-diaminodiph
enylsulphone. Analysis of the water absorption characteristics of thes
e materials using a combination of dielectric and gravimetric measurem
ents has indicated that water molecules can be found in two distinctly
different types of environments. There are water molecules which are
strongly interacting with polar groups and water molecules clustered t
ogether into sub-micro-scale cavities within the matrix structure. Cha
nges in the final cure temperature have the effect of changing both th
e extent and distribution of the types of water molecules present in t
he matrix. Validation of the diffusion coefficients obtained from the
dielectric analysis is based on a comparison with gravimetric data and
the implications are discussed. Differences observed between these tw
o different types of measurement are related to peculiarity in the die
lectric method and its extreme sensitivity to interfacial phenomena.