Аннотация:The properties of epoxy polymers modifi ed with polysulfones and polyethersulfones have been studied by dynamic mechanicalanalysis and dilatometry. Modifi ed systems have a reduced modulus of elasticity, which is probably due to a decrease in the fi naldegree of cure in presence of the thermoplastics. The resulting epoxy resin-thermoplastic systems have a relatively high glasstransition temperature and a higher level of residual stresses compared to neat cured ED-20.