Dielectric measurements were performed to determine the effect of chlo
rine, methyl and trifluoromethyl substituents on the cure of bis[N,N-b
is(2,3-epoxypropyl)-4-aminophenyl]methane with 4,4'-diaminodiphenylsul
fone and s(1-methylethylidene)]-bis[2,6-dimethyl]benzamine, and the da
ta were analysed to give gelation and vitrification points. Infra-red
measurements were also carried out during the cure process to monitor
the consumption of epoxy groups. Dynamic mechanical thermal analysis a
nd density measurements were carried out on the N,N-diglycidylaniline
system and a reduction in the glass transition temperature was observe
d to occur with the incorporation of a trifluoromethyl group into the
resin structure. Dielectric and gravimetric studies are reported on th
e absorption of water by these resins. In agreement with gravimetric d
ata for water absorption, dielectric data obtained at 10 Hz showed tha
t trifluoromethyl substitution increases the diffusion coefficient whe
reas chlorine substitution decreased it. The chlorinated resin exhibit
ed a higher than expected initial dielectric increment, which has been
attributed to the effect of a micro-porous surface structure of the r
esin. Atomic force microscopy of the resins surfaces indicates that th
e chlorinated and fluorinated resins have greater surface roughness th
an the protonated analogues, consistent with the dielectric observatio
ns. Analysis of the amount of 'bound' and 'free' water in the resin sy
stems shows that the halogenated resins have a lower percentage of bou
nd water and more of the water is in the 'free' state. (C) 1997 Elsevi
er Science Ltd.