New glass fiber/bismaleimide composites with significantly improved flame retardancy, higher mechanical strength and lower dielectric loss

• Flame retarding glass fiber (GF) composites with new resin (BDDP) were prepared.
• BDDP resin is composed of phosphorous flame retardant (DDP) and bismaleimide.
• GF/BDDP composite with a small loading of DDP reaches excellent flame retardancy.
• GF/BDDP composites also have higher mechanical strength and lower dielectric loss.
• The origin behind attractive properties of GF/BDDP composites was studied.

Novel glass fiber (GF)/bismaleimide composites with significantly improved flame retardancy, higher mechanical strength and lower dielectric loss were developed, of which the resin matrix is a new flame retarding resin system (BDDP) based on 4,4′-bismaleimidodiphenyl methane (BDM), 2,2′-diallyl bisphenol A (DBA) and [(6-oxido-6H-dibenz [c,e] [1,2] oxaphosphorin-6-yl)-methyl]-butanedioic acid (DDP). The influence of the loading of DDP in the matrix on the integrated performances of composites was intensively studied. Results show that GF/BDDP composites not only have significantly improved mechanical and dielectric properties, but also possess excellent flame retardancy. The main flame retarding mechanism of GF/BDDP composites is the condensed phase mechanism. The introduction of DDP significantly strengthens the interfacial adhesion between GF and the resin matrix, this is responsible for the attractive performances of GF/BDDP composites.