The poor toughness of liquid molding bismaleimide resin (BMI) had hampered its application in the aeronautics and space field before core-shell particles with double-layer structure were introduced to toughen BMI. The fracture morphology of BMI was studied by scanning electron microscopy (SEM) showing that the fracture surfaces of the toughened BMI were ductile fracture morphology owing to crack propagation blocked. In addition, the content of core-shell particles was adjusted to perfectly improve the comprehensive performance of BMI. Compared to the neat BMI, toughened BMI exhibits excellent mechanical performance with a tensile strength of 108.8 MPa, increased by 13.1%, an elongation at break of 3.12%, increased by 16.8%, a flexural strength of 190 MPa, increased by 12.4%, a K_Ic of 2.83 MPa/m^1/2, increased by 20.9%, and a G_Ic of 1619 J/m², increased by 54.6%. Moreover, the toughened BMI can maintain heat resistance and thermal stability, with glass transition temperature of 292.3°C and 5% weight loss temperature of 401.0°C.

bismaleimide resin  /  liquid molding  /  core-shell particle  /  toughening