Phosphorus-containing flame-retardant bismaleimide resin with high mechanical properties

Novel flame-retardant bismaleimides-based composites (P-DBA/DBE/BMIs) with excellent mechanical properties and processibility were developed by phenylphosphonic dichloride (PPD), diallyl bisphenol A (DBA), diallyl bisphenol A ether (DBE) and bismaleimide. In this system, PPD acts as a reactive flame retardant, which endows bismaleimide with excellent flame retardancy and thermal stability; DBE can improve the processibility of bismaleimide resin, and rearrange into DBA to react with bismaleimides at high temperature. Compared to the impact and flexural strength of conventional bismaleimide resin modified only by 42.86 wt% DBA, those of P-DBA/DBE/BMIs with 1.00 wt% PPD, 7.14 wt% DBE and 35.72 wt% DBA, respectively, increased 31.92 and 63.36 %. Furthermore, the thermal stability was improved markedly, and the flame-retarding UL-94 rating was increased from V-1 to V-0.