Synthesis, Thermostability and Mechanical Properties of the Ether- Based Benzoxazine Resin with Benzoyl Moiety in the Side Chain

A new ether-based benzoxazine monomer having a benzoyl moiety in the side chain is reported. This monomer showed good solubility in common organic solvents and low melting point (<125 °C). Upon heating at high temperature, the monomer converted to an insoluble and infusible resin, which showed high thermostability with a 5 wt% weight loss temperature of 380 °C and a char yield of 66% at 800 °C. Moreover, the resin exhibited good addhesion ability to metals with the shear strength of 6.5 MPa. For comparison, a benzoxazine without benzoyl unit was prepared. After cured, such a comparative benzoxazine showed a 5 wt% weight loss temperature of 322 °C and a char yield of 43%, and the shear strength of 4.7 MPa, respectively. These results indicate that the introduction of the a benzoyl moiety into the ether-based benzoxazine as the side chain can efficiently improve both of the thermostability and mechanical properties of the benzoxazine. This new benzoxazine could be used as matrix or producing the carbon/glass fiber reinforced composites, as well as the adhesives for binding the metals.