Phenol-formaldehyde resin (PF) has been widely used as an excellent thermosetting resin owing to its toughness

heat tolerance

chemical inertness and good electronic property. For high performance application

especially for expanding its usage in harsh environment demanding superior thermal and oxidation stability

further enhancement of the comprehensive properties is vital. Here

a thermally stable polyborazine (PBZ) and boron carbide ceramic microparticles (B4C) were incorporated simultaneously into the phenolic resin matrix. The curing kinetics and structure evolution of the PF/B4C/PBZ composite were investigated with differential scanning calorimetry (DSC)

Fourier transform IR (FTIR) and thermal gravimetric analysis (TGA). Both the curing initiation and peak temperatures of the composite were lowered as a result of the presence of active hydrogen atom of PBZ and the hydrogen bonding among PBZ and PF. In addition

the thermal stability of PF was improved in the temperature range of 800-1000℃

with mass loss decreased from 18.2% to 5.6%

during pyrolysis with the synergistic modification of PBZ and B4C. Furthermore

after carbonization at 1550℃ for 2 h

graphitization of PF was enhanced and interlayer distance decreased from 0.3638 nm to 0.3494 nm due to the presence of PBZ and B4C. The strategy to high performance of PF via the combination of PBZ and B4C is feasible

and it allows a better way to modify the curing behavior without compromise to thermal stability.