Synthesis and preparation of biobased benzoxazine/bismaleimide copolymers: Thermal, mechanical and dielectric properties

Preparation of low dielectric thermosetting resins by green method is a challenging subject. Herein, unique biobased benzoxazine monomer E-dea was prepared by a solvent-free method using eugenol as phenol source, and then E-dea and bismaleimide (BMI) were copolymerized to prepare poly(E-dea/BMI-0.86) and poly(E-dea/ BMI-1). The comprehensive properties including thermal, mechanical and dielectric properties of the copolymers were studied. Notably, poly(E-dea/BMI-0.86) and poly(E-dea/BMI-1) exhibit low dielectric properties with dielectric constants of 2.85 and 2.79 at 1 MHz, respectively. Besides, the glass transition temperature (Tg), the initial thermal decomposition temperature (Tdi) and the flexural strength of poly(E-dea/BMI-0.86) and poly(Edea/BMI-1) are 167.C and 169.C, 333.C and 321.C and 115 +/- 3.5 MPa and 123 +/- 4.9 MPa, respectively. The excellent comprehensive performance is attributed to the interaction between flexible and low dielectric decane segments and rigid oxazine and BMI segments.