| Abstract: | Phase separation behavior and phase morphology of mixtures of methylene dianiline (MDA)‐cured diglycidyl ether of Bisphenol A (DGEBA) epoxy oligomer and 0–30 wt % of ethylene‐(vinyl acetate) copolymer (70% vinyl acetate content) were investigated by means of small angle light scattering (SALS), optical microscopy, and scanning electron microscopy (SEM). Epoxies with EVA modified were also characterized by tensile, flexural, thermal, and hardness properties. Epoxy/EVA blend compositions, during isothermal curing, showed a ring pattern of light scattering, an increase of intensity, and a shift of peak angle to smaller scattering angle, all of which are hallmarks of spinodal decomposition. Optical microscopy studies revealed a two‐phase structure with unique periodicity and phase connectivity. Physical property measurements indicated that there was no toughening achieved by EVA modification of epoxy, and this result was explained with morphological information obtained by SEM. |
