The structural organization of liquid low-molecular-weight epoxy oligomers

The possibility of the existence and the behavior of molecular aggregates in low-molecular-weight epoxy resins were studied. The globular morphology of all liquid resins was determined using transmission electron microscopy. The lamellar morphology of crystallized ED24 was established by additionally using atomic-force microscopy. The thermal behavior of oligomeric epoxides was studied over the temperature range -100-100 degrees C. The T-g and T-ll transitions were recorded for liquid resins by differential scanning calorimetry. For solid ED24, the T-m peak of resin melting situated between T-g and T-ll was observed. The existence of the T-ll transition was substantiated by positron annihilation measurements. The morphological picture was thermally unstable and became completely degenerate at T-ll. The morphology and thermophysical parameters of the resins changed substantially after their vibrational treatment. The morphology of oligomers was shown to be "hereditarily" (genetically) related to that of the corresponding network polymers.