Composition design and property investigation of bismaleimide by branched crosslinking structure with low dielectric permittivity and high toughness

Due to the high‐power environments of electronic components, achieving the exceptional dielectric properties and mechanical behavior necessary for electronic packaging materials presents a significant challenge. In this study, a trifunctional maleimide (HTMI) was synthesized by reacting hexamethylene diisocyanate trimer (HDI trimer) with Maleic anhydride (MA), followed by the preparation of Bismaleimide (BMI) resin featuring a micro‐branching structure through its reaction with diallyl bisphenol A (DBA) ether and BMI. The intentionally designed micro‐branching structure resulted in an increase in the free volume within BMI, leading to an 8.8% reduction in the dielectric constant. Additionally, this micro‐branching architecture imparted superior mechanical properties to the BMI resin, as demonstrated by a 140% increase in bending strength and a 149% increase in impact strength of the cured product.