PHASE-SEPARATION BEHAVIOR OF THE EPOXY-CTBN MIXTURE DURING THE CURING PROCESS

To improve the impact resistance of cured epoxy resin, a carboxyl-terminated butadiene-acrylonitrile rubber (CTBN) was added. The phase separation behavior during the curing reaction was analysed by a light scattering experiment. The measurment of transmitted light intensity showed the onset and ending of the phase separation. The change of the scattered light intensity at different angles showed the process of the phase separation, such as the formation and growth of the dispersed domain. The morphology of the blend was also observed by scanning electron micrography (SEM) and was compared with the domains measured by the light scattering method. The impact strength and dynamic mechanical properties of epoxy resin of different rubber concentrations and cured at different temperature were compared, and the effect of the domain size on these properties was analyzed.