Multifunctional Benzoxazine Resins Containing Biphenyl Structures: Synthesis, Characterization and Properties

ABSTRACT In order to enhance the thermal stability and dielectric properties of benzoxazine resins, four biphenyl‐containing polyaromatic amine‐type benzoxazine resins (BOZ‐P, BOZ‐B, BOZ‐A and BOZ‐T) were prepared by molecular design in this paper, and the effects of the biphenyl structure and different substituents on the properties of benzoxazine resins were investigated. The results showed that the introduction of biphenyl structure effectively enhanced the thermal stability and dielectric properties of benzoxazine resins. Among them, the 5% thermal decomposition temperature of P(BOZ‐P) was 411.4°C, the residual carbon rate was 58.6% at 800°C, the glass transition temperature was 194.5°C, the dielectric constant was 2.808 at 10 MHz, and the surface free energy was 39.95 mJ·m −2 . P(BOZ‐T), which was introduced with trifluoromethyl group, showed the best low dielectric properties, and the dielectric constant and dielectric loss at MHz are 2.698 and 0.00758, respectively.