Effect of molecular weight on phase diagram of epoxy/polyetherimide- siloxane blends

The cloud points of blends epoxy/polyetherimide-siloxane (PEI-Siloxane) without or with curing agent methyl tetrahydrophthalic anhydride (Me-THPA) after different curing time (1 min, 2min, 3min) at 150 degrees C were determined by optical microscope. The cloud point curve for uncured and cured after different time was then obtained from the experimental results with different composition. The effects of molecular weight of epoxy on phase diagram were discussed. The miscibility of blends will be taken into account in the toughing of epoxy resins by thermoplastic PEI-Siloxane copolymer later.