Halogen-free bio-based flame retardants for epoxy resin and cyanate ester copolymer with improved fire behaviour, low dielectric constant and low dielectric loss

A halogen-free bio-based flame retardant, DBM, was synthesized from biomaterial benzaldehyde in this work. DBM was incorporated into a copolymer of cyanate ester resin and epoxy resin (EPCE), and the dielectric performance and flame retardancy of EPCE/DBM composites were explored. EPCE/10DBM containing 10 wt.% DBM, achieved a LOI value of 28.1% with a V-0 rating. In comparison to EPCE, EPCE/10DBM showed a 19.0% decrease in total heat release and a 19.1% decline in peak heat release rate. Additionally, EPCE/10DBM demonstrated both a dielectric loss of 0.00912 and a dielectric constant of 3.63, at 10 MHz. The mechanical and thermal performance of EPCE/DBM composites were also examined.