Mechanical and dielectric properties of blends of dicyanate ester and bisphenol A-based benzoxazine

Bisphenol A-based benzoxazine (BOZ) was blended with cyanate ester (CE) to improve the properties of cyanate resin. The effects of the content of BOZ on the mechanical property and dielectric property of the blends have been investigated. The results show that a suitable addition of BOZ can enhance the impact strength and flexural strength as well as reduce the dielectric constant and the dielectric loss of CE. The mechanical properties are significantly improved when the content of BOZ is 10 wt%, and the dynamic mechanical analysis reveals that the cross-link density of the blend is lower than pure CE. Scanning electron microscopy analysis shows distinct characteristics of ductile fracture of the blends. In addition, the dielectric constant and the dielectric loss of modified system decreases, compared with the curing CE. The optimal addition amount of BOZ resin is 15 wt% for the dielectric properties. The blend of a suitable addition of BOZ still remains a good thermal resistance. All these changes in properties are closely correlated to the copolymerization between BOZ and CE.