Thermal and mechanical properties of PPO filled epoxy resins compatibilized by triallylisocyanurate

A series of blends has been prepared by adding a poly(phenylene oxide) (PPO), in varying proportions, to an epoxy resin cured with dicyandiamide. All the materials show two‐phase morphology when characterized by SEM and DMA. SEM and DMA indicate that partial mixing exists in all the blends especially with high PPO content. This implies that the epoxy oligomer or low crosslinking density epoxy exists in the PPO phase after curing. The tensile strength and modulus of these blends are nearly independent of the PPO content, while the fracture toughness (GIC) is improved by PPO. However, the two‐phase particulate morphology is not uniform. In order to improve the uniformity and miscibility, triallylisocyanurate (TAIC) has been used as an in situ compatibilizer for the polymer blends of epoxy and PPO. SEM and DMA reveal improvement of miscibility and solvent resistance for this system. The fracture toughness of these TAIC‐modified systems are also improved by adding TAIC (0–20 phr). © 2000 Society of Chemical Industry