Studies on the phase separation of a polyetherimide modified epoxy resin. VI. Effect of surface energy on reaction-induced phase separation of epoxy resin modified with polyetherimide

The effect of surface energy on the phase separation of polyetherimide modified epoxy systems is studied by time-resolved light scattering (TRLS), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), and rheometer. Scanning electron microscopy shows that phase separation of F-blend system goes further and finally, smaller epoxy-rich particles and thicker polyetherimide (PEI)-rich layers are generated. Differential scanning calorimeter and TRLS experiments indicate that the F-PIP/Epoxy blend has a lower curing rate and phase separation rate than the P-PIP/Epoxy blend. Rheological behavior displays that the viscosity of F-PIP/Epoxy blend is lower than that of P-PIP/Epoxy blend. By studying the properties of different PIP surface the F-PIP and P-PIP give different surface energy and it could be concluded that kinetics is a control factor in the phase separation of the two blends due to their difference of surface energy of PEI chain.